Low cost energy efficient house concept in Latvia

Low cost energy efficient house concept in Latvia 7th semester elective dissertation

Author: Alina Janesa Consultant: Bent Michael

Hansen

Campus Horsens, Denmark Bachelor of Architectural Technology and Construction Management October 2014

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TITLE PAGE DISSERTATION TITLE: Low cost energy efficient house concept in

Latvia 7th semester elective dissertation

CONSULTANT: Bent Michael Hansen AUTHOR: Alina Janesa DATE/SIGNATURE: 31 Oct 2014 STUDENT IDENTITY NUMBER: 163642

NUMBER OF COPIES: 2 NUMBER OF PAGES: 42 NUMBER OF CHARACTERS: 77 709

FONT: Arial 12

All rights reserved – no part of this publication may be reproduced without the prior permission of the authors.

NOTE: This report was written as a compulsory student assignment in the 7th semester Architectural Technology and Construction Management degree course – no responsibility is taken for any advice, instruction or conclusion given within!

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Preface This report is written as an part of the final examination for the Bachelor of Architectural Technology and Construction Management education.

Writing dissertation in my opinion is a great opportunity to make a deep research and collect information about the topic, which is the most interesting for me. Possibility to choose subject on my own ensures motivation and keeps me inspired during the work on report.

I started my studies in constructing architect program, because I was willing to get more knowledge in architectural technology area-technical part of projects. It can be explained by my opinion that functionality of the building has bigger value than its design. I kept this thought throughout semesters and therefore now, in my final 7th semester, I chose topic which will help to find how architecture can improve daily life of ordinary people at the same time promoting sustainability.

The name of my subject is “Low cost energy efficient house concept in Latvia�. The main goal of the dissertation is to find construction of energy efficient house, which at the same time would be affordable for average Latvian citizen. Sustainable architecture unfortunately is not very popular and recognizable in Latvia. Most of the people look at it with skepticism and distrust, due to high costs of this type of housing. One way to promote energy efficient architecture is to make it low-cost and economically advantageous for the country itself.

Aknowledgments First of all I would like to thank my consultant Bent Michael Hansen for given encourage and help regarding my 7th semester dissertation. He gave me guidance in choice of the subject from the first steps towards report and his belief in my strengths was motivating me throughout the writing process. Also I would like to thank Rihards Starostnieks for his willingness to participate in interview and provide with relevant information regarding family house construction in Latvia.

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Abstract This report has been written as an individual dissertation with elective subject in 7th semester Constructing Architect degree course.

Dissertation contains research on nowadays essential and widely discussed topicenergy efficient housing trying to find a way, how to achieve sustainability using local materials and at the same time keeping affordable for ordinary Latvian family price of the project. Technology of building construction with low energy contribution is well developed and has detailed descriptions, but because of pattern saying that it requires high initial expenditure, became the main reason why people in Latvia are having rejecting attitude towards sustainable living. Finding a way and showing how to build energy efficient house with smaller investment will be a step towards raise of sustainability in one of the Baltic countries. Research is based on primary and secondary empirical data, which combines investigated and carefully selected theory with my own observations and experience. To find restrictions regarding energy consumption in single family houses, I used data from Latvian building regulations and European Directives concerning energy consumption. Main section collects data about factors, which are influencing energy efficiency of the buildings, comparison of building materials and innovative heating systems that can be suitable for family house construction. Conclusion displays the most convenient product and system described in main section, as well as states possible problems regarding efficient building execution in Latvia.

Keywords Climate change Building Standarts Directive 2012/27/EU Client demands Building envelope Building orientation Local manufactures Building components Shading Renewable energy Ventilation Illumination Funds 4

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Contents Preface ................................................................................................................................................ 3 Aknowledgments ................................................................................................................................ 3 Abstract ............................................................................................................................................... 4 Keywords............................................................................................................................................. 4 List of illustrations ............................................................................................................................... 6 List of tables ........................................................................................................................................ 6 Introduction with Problem formulation ................................................................................................. 7 Background information and presentation of subject........................................................................ 7 Choice of the subject .......................................................................................................................... 7 Problem statement and research questions....................................................................................... 8 Delimitation ........................................................................................................................................ 8 Choice of theoretical basis .................................................................................................................. 8 Choice of research method ................................................................................................................. 8 Overall structure of report .................................................................................................................. 9 Introduction .................................................................................................................................... 9 Main section.................................................................................................................................... 9 Conclusion ....................................................................................................................................... 9 Main section.......................................................................................................................................... 10 Regulations, Standards and demands................................................................................................... 10 Importance of energy consumption of buildings.............................................................................. 10 Regulations and Standards on energy efficient single family house construction in Latvia............. 12 Conclusion ..................................................................................................................................... 14 People demands in relation to typical family houses ....................................................................... 15 Conclusion ..................................................................................................................................... 17 Building energy consumption-key factors ............................................................................................ 17 Climate .............................................................................................................................................. 17 Building envelope.............................................................................................................................. 18 Building shape coefficient ............................................................................................................. 18 Building orientation ...................................................................................................................... 19 Buidling components .................................................................................................................... 19 Conclusion ..................................................................................................................................... 21 Thermal insulation ........................................................................................................................ 22 Conclusion ..................................................................................................................................... 23 5

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Thermal bridges ............................................................................................................................ 24 Air tightness .................................................................................................................................. 24 Windows ....................................................................................................................................... 24 Shading/Overhangs ....................................................................................................................... 25 Conclusion ..................................................................................................................................... 26 Building services................................................................................................................................ 26 Heating .......................................................................................................................................... 27 Conclusion ..................................................................................................................................... 29 Ventilation..................................................................................................................................... 30 Heat recover (MVHR) .................................................................................................................... 31 Conclusion ..................................................................................................................................... 31 Hot water ...................................................................................................................................... 31 Illumination ................................................................................................................................... 32 Conclusion ..................................................................................................................................... 34 Finances ............................................................................................................................................ 35 Conclusion ............................................................................................................................................. 36 List of references................................................................................................................................... 37 List of electronic sources .................................................................................................................. 37 List of figures ..................................................................................................................................... 42

List of illustrations Fig.1Global annual emissions of anthropogenic GhGs from 1970 to 2004 (page10) Fig.2CO2 Emissions in Eurpean Union in 2007 (page 11) 2 2 Fig.3 Impact of building shape on annual heating energy for a small 144 m (1500 ft ) building in a coldclimate.(page 18) Fig.4 Room layout according cardinals (page 19) Fig.5 Structure of primary resource supply and share of renewable sources (page 27) Fig.6 Final energy consumption in residential sector in Latvia, 2010 (page 27) Fig.7 Heat energy expenses using different heat sources (page 29)

List of tables Table1. U-value requirements for building envelope in residential buildings and energy consumption value in different time periods, including current demands (page 13) Table 2. Dynamics of built houses in Latvia (page 15) Table 3. Building materials for external wall construction (page 20-21) Table 4. Summary of insulation material qualities (page 22-23) Table 5 Advantages of disadvantages of different window frames (page 25)

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Introduction with Problem formulation Background information and presentation of subject Techniques such as solar orientation, thermal flywheel effect and natural ventilation, which represents passive solar building design were practiced for thousands of years, but due to different factors along the history of civilization, were gradually abandoned. Importance of passive solar principles was recalled over again in 20th century, greatly improving and developing technologies of low-energy buildings.

First Passive house standards were mentioned in 1998 and the first residence was built in 1990, characterizing the history of low-energy buildings as long enough to promote and specify conditions related to new vision of architecture. Since first concept were built approximately 20 000 passive houses all over the world, located mostly in Germany, Central Europe as well as in Scandinavian countries.

As a part of the Europe, Latvian building industry was also introduced to innovative solutions regarding low-energy consumption architecture, but sadly new discoveries weren’t put in practise enough to face a great evolution and sustain. More insistent promotion and careful introduction to the “green” housing would help Latvian citizens accept innovatory technologies and consider implementation of some of them into their own houses. Finding a way how to build energy efficient buildings by affordable price would be an encouragement for people to consider low-energy technologies for their own family houses.

Choice of the subject Building area is one of the industries constantly facing changes in regulations, construction technologies, appearance and production of new materials, therefore it is necessary to follow advanced methodologies as it can clearly improve traditional techniques. Architecture directly influences people comfort and safety and it’s a great opportunity to noticeably improve daily life of any person. I was always interested in ways how with help of architecture positively affect people well-being, that’s why the topic of my dissertation in the final semester of constructing architect program is chosen to make a research regarding promotion of sustainability among people in my home country-Latvia. By the end of investigation I would like to find a way, in which it is possible to build low-energy family houses in Latvia without extreme money investments and with use of local materials.

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Problem statement and research questions Problem statement can be expressed in question: -What could be the construction suitable for common single family house in Latvia, which would provide sustainability, use of local materials and affordable price?

Research questions that will be reviewed through the main section until the final conclusion are: -What are the factors that are needed to be taken into consideration before starting work on possible construction?

Which requirements regarding single family houses and energy efficiency are mentioned in Latvian Building regulations?

How climate can influence choice of construction?

What are people needs in relation to typical family houses?

-What construction methods and materials can cover all the factors and provide good living conditions for Latvian inhabitants?

-What possible financial support can be received if decision on energy efficient building construction is made?

Delimitation Dissertation will inspect Building regulations of one country-Latvia, as research will be made only regarding this particular country. Construction of low-energy house will be adjusted to Latvian climate and people demands. In dissertation will be described and analysed construction materials and energy efficient heating solutions that are available on Latvian market and have already been implemented in projects before.

Choice of theoretical basis Information will be collected and analysed from such quantitative empirical data sources as Building regulations, The Building Law and General Construction Regulations, Assessment of the Intergovernmental Panel on Climate Change, Directive 2012/27/EU, Internet publications by energy efficient heating system manufactures and building material producers as well as institutions and specialists in current topic. Qualitative empirical data was gained by interviewing Rihards Starostnieks, one of the architects working in “I. P. Projekts� Ltd. in Latvia.

Choice of research method To find answers on problem statement and research questions I will use secondary data, which will be found in different empirical data sources described in the previous chapter. Secondary data will be collected, examined and combined in the main section of the dissertation. I will use this type of methodology, because construction processes and building technology for energy-efficient houses was already found by professionals, my goal is to use this information and choose the most suitable of 8

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them for housing in Latvia, to meet standards and requirements of this country.

Research will be described using quantitative and qualitative data, showing investigations in both: text and numbers.

Overall structure of report Report consists of 3 main chapters: Introduction This part describes background and choice of the subject. It gives information about theoretical basis and research methods. At this stage I’m introducing to my aims regarding dissertation, what exactly I’m willing to achieve by the end.

Main section Main section contains research, which shows investigations of the chosen subject.

Research consists of analysis based on publications, interview, theories and facts related to my topic.

The main section starts with demands stated in Latvian building regulations that influence single family house construction. It is done to acknowledge limitations according house building and energy efficiency. Getting introduced with requirements from the beginning prevents project from being rejected after work on drawings will be done.

After the investigation of all the necessary regulations will be done, other important aspects will be described. As for building construction I would like to choose local materials, research of the possible products will be represented. I will carefully take a look on already presented methods of energy efficient housing technologies and evaluate, which of them could be suitable for low-cost building project.

Conclusion Conclusion will give an answer on the main question: which materials and building technologies could be used to build an affordable and sustainable house for Latvian family with average incomes? I will give my opinion on present situation regarding sustainable housing in my home country, as research on environmentally friendly architecture will be made during dissertation preparation.

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Main section Regulations, Standards and demands Importance of energy consumption of buildings The reason for awareness of building energy consumption is a radical rise of CO 2 emissions during the last years, which caused global warming and due to that evident climate changes. A synthesis report –Assessment of the Intergovernmental Panel on Climate Change, issued in 2007 by the three Working Groups, contains observations on climate changes, their causes and consequences, as well as possible mitigation options. By the data of synthesis report, global warming has caused the sea level rise reaching an average rate of about 3,1mm per year. In the past 100 years average Arctic temperatures have increased almost twice the global average rate. Data shows that an average ice amount in Arctic sea has reduced by 2,7% per decade since year 1978. Climate changes have been detected also in North Atlantic part, where tropical cyclone activity has increased evidently since 1970. One of the climate change causes is greenhouse gas (GHG) emission radiative properties and lifetime in the atmosphere. Amount of global GHG emissions caused by human activities had a significant growth between 1970 and 2004, when the number of increase reached 70%. Carbon dioxide represents 77% of total GHG emissions and shows the highest rate of growth during 1995-2004, therefore it has a relevant role in the total greenhouse gas reduction process.

Fig.1Global annual emissions of anthropogenic GhGs from 1970 to 2004.

Present level of GHG or raise above the current level may cause further changes in the world climate system. Due to so persuasive global events, different systems and sectors, for instance ecosystems, water, food, health, coasts, industry, society and settlements may face several changes. Mitigation options are focused on energy efficiency and usage of renewable energy sources as it would generate sustainable development and synergy. The positive mitigation results can be achieved by changes in present lifestyle and behaviour, which includes improvement of consumption patterns, more deliverable building occupant behaviour, revised transportation management and modernized manufacture industry.

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In order to stimulate mitigation actions, different policies and instruments shall be issued by governments. Effective ways leading to emission reduction and implementation of sustainable technologies are integration of climate policies in broader development policies, stated regulations and standards towards emission levels, taxes and charges setting the price for carbon, voluntary agreements between industry and governments which encourages usage of innovative technologies, campaigns promoting behavioural change and research, development and demonstration (RD&D). Policies encouraging energy efficiency and renewable energy usage are tend to reduce local amount of pollution and at the same time are economically beneficial. UNFCCC and Kyoto protocol are global programs established to control energy consumption worldwide and expedite creation of national policies, such cooperation is an effective way to achieve cooperation at the international level. Report on Buildings and Climate Change published in connection with United Nations Environment Programme (UNEP) in 2009 was issued with main purpose to provide information about greenhouse emission reduction possibilities within the building industry.

Fig.2CO2 Emissions in Eurpean Union in 2007

Importance of GHG minimization in construction field can be explained by the fact that buildings contribute up to 30% of total amount of the global greenhouse gas emissions and consumes up to 40% of energy, therefore control over particular industry would lead to prevention of further effects caused by climate changes. As buildings have relatively long lifespan, it is important to take into consideration the most energy efficient approaches already at the design phase, especially regarding heating, cooling, ventilation and lighting applications, which generates 80% of greenhouse gas emissions. Other energy consuming events such as material manufacture, transportation, construction process, maintenance, renovation and demolition normally contributes to 10-20% of energy usage. Process of energy efficiency promotion unfortunately faces different barriers that slow positive impact on emission levels. To overcome these barriers, information stating energy performance standards, accurate data about the Building Sector, ways to provide practical knowledge on energy efficient construction solutions and frameworks for consulations with all major stakeholders should have been included in national climate change strategies and issued by the governments. Besides different standarts and regulations every building during its design phase should also consider wide range of interrelated facors, for example location, climate, special demands, supply and source of energy, building materials, design and function as well as level of client incomes and behavior of occupants.

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Regulations and Standards on energy efficient single family house construction in Latvia Latvian Building regulations are divided into 4 main chapters: Project preparation, Design, Construction and Exploitation. These chapters in total are consisting of 37 different Construction Standards. As the main aim is to find information regarding construction of single family houses and special demands with reference to energy efficiency, I will use following Standards from the chapters -Project preparation: LBN 002-01 “Thermal engineering of building envelope” (updated 01.01.2003.)

LBN 003-01 “Construction Climatology” (updated 01.09.2001.)

-Design: LBN 209-09 “Low-rise residential buildings” (updated 01.11.2009.)

LBN 231-03 “Heating and ventilation in residential and public buildings” (updated 01.01.2004.)

All above mentioned Construction Standards are valid until 1st of July 2015.

Additionally I will analyse information from General Construction Regulations (updated 01.07.1997.) and Building Law (updated 13.09.1995.) as they might contain relevant information concerning my subject. Regulations named “Calculation method of building energy performance”, “Building energy certification rules” issued by Cabinet of Ministers in 2013 and “Energy Efficient Buildings Strategy” issued by The Parliament in 2012, might have a direct relevance to the research. These regulations were established in relation to Directive 2012/27/EU of the European Parliament and of the Council published on 14th of November 2012. Directive was released to decrease dependence on energy imports and reduce greenhouse gas emissions and therefore presents legal obligation to create policy measures concerning promotion of more efficient use of energy within the Union. Reduction of primary energy consumption by 20% until the year 2020 is the European Councils main objective. To achieve named goal, Member States were required to deliver strategy describing National Reform Program. As building sector is one of the categories included in the Directive that could boost energy efficiency and spread innovative technological solutions, Latvian Government issued their own outline regarding sustainable growth.

The Building Law prescribes relations between participants of construction processes, their rights and responsibilities during and after execution. General Construction Regulations determines the requirements for all type of structures describing such parts as project preparation, design, building execution, demolition as well as order of mentioned procedures. Both documents are not observing energy efficiency of buildings, but introduces to actions that must be made so the building can be accepted by municipality.

Building Code LBN 209-09 “Low-rise residential buildings” regulates general requirements for construction, reconstruction and renovation cases. Regulations 12

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states that composition and design of spaces is determined by the client with the only condition that it will not interfere with requirements defined in Building Standards, which gives a certain freedom when designing the outlook and interior of single family house.

LBN 231-03 “Heating and ventilation in residential and public buildings” defines rules regarding fire safety and space requirements for technical rooms, contains description of ventilation systems and their components, which is relevant during planning and installation process. In case of this report, this data is not essential as dissertation will point out only possible solutions and technologies in general without identifying so detailed information.

Above described Standards as well as The Building Law and General Construction Regulations were last time updated between years 1995 and 2009, when energy efficiency started to be controlled by restrictions, but still didn’t have very high demands against energy use. LBN 002-01 “Thermal engineering of building envelope” was first formed in 1980. The Building Code shows methodology of Uvalue calculations with the main aim to promote energy-efficient building components and lower energy use in houses. In the past houses in Latvia were mostly constructed from wood, bricks, aerated concrete and expanded clay blocks. Building code was later on developed in 1992 and 2003, when buildings started to be designed with large glazed surfaces.

Table1. U-value requirements for building envelope in residential buildings and energy consumption value in different time periods, including current demands

Building components 1980 1992 2003 Roof and structures in contact with the air 0.90 0,25-0,40 0,2·k* Ground slabs, floors in contact with the soil 0,5 0,25·k External walls with mass less than 100kg/m2 W/(m2K) 1,1 0,33-0,50 0,25·k 2 External walls with mass 100kg/m and more Windows, doors 2,4 1,9-2,4 1,8·k Cold bridges 0,2·k *Temperature factor k=19/ (Tind-Tout), depends on geographical position of the building, can vary from 0,95 to 1,09. kWh/m2 per Heating energy consumption 150-200 100-130 70-90 year In 2004 by the European Parliament and the council was issued the first directive on energy efficiency. It was incentive for the Latvian National Reform Programme establishment, which further affected building industry. The latest update of the directive was made in 2012 (Directive 2012/27/EU) and was the reason for “Calculation method of building energy performance”, “Building energy certification rules” and “Energy Efficient Buildings Strategy” review.

These regulations contain information about energy-certification of already existing buildings and temporary energy certification of designed buildings. Energy certification is performed by independent expert, which during 5 days after certificate issuance registers building in energy-certification register.

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Buildings are divided in following energy classes: A-corresponds to characteristics of zero-energy house B- heating indicator does not exceed 40 kWh/m2 per year C- heating indicator does not exceed 50 kWh/m2 per year D- heating indicator does not exceed 60 kWh/m2 per year E- corresponds to building type with average energy consumption F- corresponds to energy parameters for residential buildings stated in regulations To realize certification, expert analyses quality and applicability of data provided for calculations, determines buildings energy-efficiency class using “Calculation method of building energy performance” and issues temporary energy certification.

Evaluation of annual energy consumption covers such technical installations as heating, cooling, ventilation, hot water supply and lighting. Energy efficiency class is likewise affected by U-value parameters, orientation towards cardinal points, solar influence, inner loads, outdoor and indoor climate.

“Energy Efficient Buildings Strategy” suggests some of the systems that could help to reduce energy consumption. These high-efficiency technologies apply to heating and cooling installations. Recommendations propose use of cogeneration, heat pumps, renewable energy sources for decentralized energy supply and district heating/ cooling systems. Regarding sustainable solutions The Latvian National Reform Programme is also mentioning use of biomass, solar collectors and solar panels, which could be financed by Climate Change Financial Instrument (CCFI) Latvian state budget program. To boost strategy on energy-efficiency, program proposes review of minimal U-value requirements, promotion of zero-energy house construction as well as development of conditions for tax revenues in cases of energy-efficient housing and renewable energy usage in buildings.

Conclusion Latvian Building Regulations, Building Law and General Construction Regulations are not mentioning certain standards regarding energy efficient house constructions as well as not mentioning direct restrictions that would affect overall design of the building, choice of construction materials, technical installations or location on the site. It gives client certain freedom to choose between different construction methods and technologies, unless building components will meet U-value requirements mentioned in Table 1. In order to promote energy efficient building methodologies, is given opportunity to perform buildings energy-certification, therefore “Energy Efficient Buildings Strategy” advises to consider implementation of sustainable solutions, which would lead to higher energy class.

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People demands in relation to typical family houses After Latvia joined European Union in 2004, large amount of investments from Member states caused rapid rise of building industry. In time period between 2003 and 2009 amount of buildings has grown 10 times and area of the constructed houses almost 6 times. Table 2.Shows the dynamics of houses built in Latvia from 2003 till 2008. It can be seen that average area of the house decreased by 100 m2, which points on people unwillingness to pay utility and maintenance costs for unused space. The average size of total living space on one person in the end of 2008 was 27 m2. From all single family houses that have been accepted in 2008, 17% are 1storey buildings, 77% have 2-storeys and 3% are having 3 and more storeys. The average area of one single family house was 244 m 2.

Table 2. Dynamics of built houses in Latvia

Indicator changes over the years Indicator 2003 2004 2005 2006 2007 2008 08/03 Area of the built houses (thsd. m2) 194,2 452,3 552,2 812,6 1188,4 1153,2 493,82 Growth (%) 7,7 133 22 47 46 -3 X Amount of the built houses (units) 830 2821 3807 5865 9319 8084 20,3 Growth (%) X 631,41 28,7 101,72 24,95 -14,43 X 2 Average area of the one built house (m ) 234 160 145 139 128 143 0,61 Growth (%) X -31,5 -9,5 -4,5 -8,0 11,9 x To collect data about client demands on single family houses, I made an interview with Rihards Starostnieks, an architect working at the company “I. P. Projekts”. “I. P. Projekts” was established in 2004 and specializes in design and execution of residential, public and commercial buildings. Architecture office has an archive of 2500 already designed standard projects, which are prepared for construction process, but can be adjusted to client demands.

1. What single family house size is the most requested among clients?

Clients are giving priority to 2-storey family houses with total area up to 220 m 2.

Usually this space includes kitchen, living room, 3 bedrooms and technical rooms, storages. Buildings above 220 m2 are requested if it involves construction of garage or other utility rooms.

People older than 40, are usually demanding 1-storey single family houses with are up to 150 m2.

Ordinary buildings are constructed without basements. In the last 15 years, there were only 3 cases, when basement was requested, which means that this solution is not a typical for Latvian single family houses.

2. What are typical client demands concerning room layout and plan of the building in general?

Ordinary client demands concerning room layout: 15

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Ground floor: open living room combined with dining room and kitchen, one bedroom, 1 bathroom and toilet, technical room and garage.

1st floor: usually there are arranged 3 or 4 bedrooms with separate bathroom and toilet. In some cases clients request each bedroom to have its own restroom.

3. Which building materials are commonly used for load-bearing structures, roofs, facades?

For external load bearing wall structure are preferred expanded clay blocks or aerated concrete blocks. Solution when bricks or cast-in situ concrete elements are used, is not common. Times to time wooden frame wall structures are ordered.

The planned wall thickness constructed of expanded clay blocks for load-bearing walls is not smaller than 300 mm, for aerated concrete blocks this value is even bigger. Blocks are insulated with 150 mm thick stone wool.

Storey partitions are executed from reinforced concrete slabs and insulation as well as cast-in situ concrete.

Traditional roof construction has wooden structure consisting of rafters and insulation in between.

Façade finishes vary from simple plaster coating up to decorative bricks and wooden planks.

4. What is average price for single family house in Latvia?

Roughly calculating, construction of the building frame costs approximately 550-600 EUR/m2.

5. Are you considering installation of any energy efficient solutions in new house projects?

Until now, we didn’t have experience with such solutions, also there were no demands concerning installation of any energy efficient systems. Latvia doesn’t have enough amount of sunlight, therefore solar panels and other innovations are having a long pay-back period.

6. Are you using such methods as natural light, building orientation on the plot, shading appliances or the most convenient window position in order to reduce energy consumption?

Usually during design process we are trying to meet these requirements, but client is the one who controls everything. Client is the one, who makes a decision on size and location of the windows.

7. Which heating and ventilation systems are used the most? Are you taking into account usage of any energy efficient systems?

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In Latvia the most are used wood pellet boilers. In locations, where gas pipeline connection is available, gas heating is considered. Ordinary houses are additionally equipped with wood-burning fireplace.

Sometimes heating system has to be provided by the usage of geothermal heat pump, but it has been implemented only in 2-5% of total amount of executed buildings.

Conclusion Commonly single family houses in Latvia are having total area of more than 200 m 2, usually incorporating open kitchen connected to living room and dining room, several bedrooms, utility room and garage with technical rooms and storages. External load bearing walls are built using expanded clay blocks or aerated concrete blocks and 150 mm thick stone insulation. Roofs traditionally are having wooden structure. Most of the family houses are having wood pellet heating system. Regarding energy efficient solutions, many sustainable methods are not practised, as clients are not showing interest in their installation. In cases when client is not informed about energy saving solutions, but he is the one who decides on building components and technologies, some of the possible energy efficient solutions can be missed, for example right position and size of windows, building shape.

Building energy consumption-key factors Not only the right choice of technical installations and mechanical appliances, but also design it-self leads to energy savings, as it will be able to reduce amount of time, when mechanical systems has to run and therefore amount of contributed energy. Especially in case, when building should be constructed with lower expenses, such factors as climate, position of the building on plot, convenient use of light and air tight building envelope should be taken into consideration. These aspects will not require high money investments, but will be a tool in energy saving accomplishment.

Climate Latvia is located in the temperate zone at the Baltic Sea. Climate is defined by the geographical position and plain topography. In Latvia are dominating south, southwest and west winds, with average speed of 3,6 m/s. There are an average of 160 to 180 cloudy days a year and the sun is shining approximately 1790 hours per year, which is about half of the possible sunshine duration time (in a clear day). In winter sun rises 9-10 degrees above the horizon. In summer sun rises to 55-57 degrees above the horizon. The amount of direct radiation during the winter is less than 20-30% and 50-60% from March to September. The average annual relative humidity is 81%. Need for heating up the buildings in Latvia is a significant factor higher than ordinary in Europe. There are 4035 heating degree days in Latvia compared to 3067 heating degree days on average in Europe.

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Building envelope Primary purpose of a building is to ensure protection of inner space from noise, wind and weather, providing security, privacy and liveable internal temperature. To achieve satisfying living conditions, occupants must feel thermal comfort. Buildings heat balance can be considered when the sum of heat gains (solar and internal gains) equals the sum of heat losses (transmission and ventilation losses), therefore the main purpose of building envelope is to keep heat volume above a set temperature at any weather conditions. Keeping the inside temperature of the envelope constant and is the task of heating air conditioning systems.

To ensure that all energy is conserved, construction must have sufficient insulation material together with high performing windows, air-tight envelope and thermal bridge absence.

All elements that separate indoor area from outer space: external walls, roof, floor and windows and doors must be chosen with care as choice of materials for building envelope components has a significant role, especially in case of sustainable construction when preferable are renewable and recyclable materials.

Building shape coefficient Building shape coefficient is an important factor in building energy saving design and energy efficiency evaluation. Shape coefficient is calculated as a ratio of the outersurface area to its enclosure volume. The larger is coefficient, the more complex is buildings shape and greater chance for heat gain and loss to transmit through the surface, which will lead to energy consumption increase. It is preferable to choose compact shape of the building to minimize the losses and gains through the envelope, especially in cold climates, where shape factor should be as low as possible. Shape coefficient in residential buildings is influenced by the plane layout of the building, its height and design of the envelope, whose shape in order to avoid complexity shall be tendered toward a cube.

Fig.3 Impact of building shape on annual heating energy for a small 2 2 144 m (1500 ft ) building in a coldclimate.

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Building orientation The right position of building towards passage of the sun across the sky will bring more light into the house, let in passive solar gain, reduce overheating and save energy used for cooling system. To achieve maximum usage of solar gain during winter season, building should be oriented and have the largest window area within 30° of South. Usually East and West orientations are avoided due to very low radiation level in winters and complicated solar control in summers. To obtain best results from house orientation on the site, building should have rectangular shape with the long side facing the south. The percentage of glazing surface related to the floor area should represent 20% when positioned to the South and 5% to the North.

Location on the plot should be connected with room layout in the house to achieve comfortable indoor environment. North orientation is preferable for bathroom, storage, workroom, staircase, laundry and other utility rooms due to low level of daylight amount and big possibility of cold winds. East orientation offers early morning solar gain providing natural light and refreshing feeling without overheating consequences. Such conditions are Fig.4 Room layout according cardinals advantageous for bedroom, and kitchens.

South orientation provides possibility to arrange large glazing areas that will bring into the room good daylight most of the day. In winter time sunlight penetrates deeply in interior space providing passive heating, but in summer sunlight can be blocked by horizontal overhangs to avoid overheating. South orientation is beneficial for living rooms and other areas where family spends the most of the time. West orientation causes overheating of the space during summers and afternoon hours, therefore spaces positioned to the west are not suitable for kitchens, rooms for working and studying.

Buidling components Energy efficient construction includes not only lower energy consumption during the lifetime, but also use of renewable and recycled materials. As the main goal of Directive 2012/27/EU is to limit climate change, it as well includes more efficient production of building materials, which could lower environmental pollution, waste and energy requirements for production. Therefore it is preferable to choose local building materials, which don’t require high costs of distribution, maintenance and recycling.

Local minerals that can be found in Latvia are: dolomite, clay for bricks and clay for expanded clay production, sand and gravel mix, sand, gypsum, clay for cement,

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limestone for cement and limestone for lime production. The most extracted minerals are dolomite, sand, gravel and limestone for cement.

Sources of wood also give opportunity for different wooden element production.

Timber industry achieved 22, 4% of the total industry output, while construction material industry 5, 9%. It includes manufacture of insulation, windows, cement, concrete, plaster, paint, bricks, construction blocks, reinforced concrete.

There were already proposed some of the innovative ideas regarding material production. New products are clay-dolomite composite material, inorganicpolymer or low-temperature geopolymer produced from clay, hybrid binder as a mixture of clay and dolomite powder, peat activated binder. All the introduced materials have a potential on the Latvian market as they are produced out of the most widespread Latvian minerals, but novation characteristics are equal or better than currently used products, but require less energy during manufacture process.

There is a wide range of companies in Latvian building industry that at the moment offers construction materials for energy efficient houses. In July 2010 “BELSS” Ltd. together with Latvian Ministry of Environmental Protection and Regional Development and “BM-projects” Ltd. developed a project, whose main aim is to introduce people with energy-effective solutions regarding family house building and guide to the different manufactures of eco-friendly building materials. It shows that Latvian market can offer progressive solutions and is up-to date with modern materials for energy-efficient house construction.

Typically load bearing wall structures in family houses are having masonry construction built from bricks or KERATERM ceramic blocks, lightweight construction from expanded clay blocks or aerated concrete blocks, wooden structures both prefabricated and made on site and cast-in situ concrete structures. From interview with Latvian architect can be concluded that at the moment preferable is external wall construction from expanded clay or aerated concrete. Table 3.collects information only regarding locally produced building materials, as usage and promotion of Latvian manufactures was an aim of the report.

Table 3. Building materials for external wall construction

Material and companies producing Aerated concrete blocks: AEROC Ltd.

Ceramic blocks: LODE Ltd.

Characteristics +can be built without additional insulation +easy to apply exterior finish -brittle -low water resistance +ecological +good thermal resistance

Product AEROC EcoTerm Plus

KERATERM 44 KERATERM 25 KERATERM 17,5

Size (mm) LxWxH 600x500x200 600x375x200 600x300x200

245X440X238 375X250X238 470X175X238

Thermal conductivity λ (W/ mK)

Uvalue W/(m2 K)

Price (EUR /m3)

0,072

0,17 0,22 0,28

71,69

0,129 0,227 0,190

0,15 0,27 0,38

80,17 78,09 79,74

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Expanded clay blocks: KOLLE BETON Ltd. BUVEMA Ltd.

Prefabricated wooden wall elements: TIVO BĹŞVE Ltd. WOOD PANEL HOUSES Ltd. GLASS&WO OD Ltd. TRINITY CAPITAL Ltd. BUVNIEKU ALIANSE Ltd. Cast -in situ Concrete: ZV-Group Ltd. A.B.Tons Ltd.

+can be fast executed compared to standard brick +can be used for foundation construction -problematic construction work during the winter time +natural material +fast construction process +easier to be threatened than KERATERM blocks +can be used for foundation construction -has lower thermal resistance than ceramic blocks, therefore requires insulation -problematic execution process during winter +fast execution process, can be realized in any season +provides controlled quality +use of local materials -limited design options

+fast and affordable technology +wide variation in forms +extremely durable -low vapour permeability

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K BIOKS

SKC (Hollow concrete blocks) BBR 3/200 or BBR 5/200 BBR 3/250 or BBR 5/250 BBR 3/300 or BBR 5/300

Prefabricated wooden wall elements: -Wooden siding -Batten/Air gap -Wind barrier (fibreboard) -Wooden studs (spruce) /Cellulose insulation (70 kg/m3) -OSB -Gypsum board Lightweight Concrete medium

490x200x185 490x250x185 490x300x185 390x240x190

0,18 or 0,28

89,53

0,34-0,56

77,48

490x200x185 490x250x185 490x300x185

85,91 or 91,06

0,21

25x70 25 195x45

10 12,5 200 200

0,1-0,3 0,4-0,7

0,25 0,61

Conclusion The most advantageous material for external wall construction which combines lowest price and good thermal conductivity characteristics, are aerated concrete blocks AEROC EcoTerm Plus. Using 500 wide blocks attachment of additional insulation material can be avoided. Expanded clay blocks are more expensive and 21

≈170 EUR/ m2

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will require insulation layer to achieve higher U-value. Ceramic blocks are having good thermal conductivity properties, but construction process might be more difficult, blocks are more expensive compared to AEROC products and will demand special exterior finish. Buildings from prefabricated wooden elements would be fast to execute, but elements would require additional transportation and installation costs, the same as cast-in situ concrete structure.

Thermal insulation Insulation has a great impact on energy usage in building maintenance. European Parliament and the council in the Energy Efficiency plan of 2011 states that 40% of the European Union’s final energy consumption belongs to building industry. 75% of the energy that is consumed in building is used for heating up the space, therefore by the Centre for European Policy Studies it was concluded that energy-efficient insulation is the finest way to CO2 emission reduction and limitation of climate change.

When choosing environmentally friendly insulation, not only its high insulating parameters, but also material production process and disposal should be taken into consideration. At the moment the best insulation materials, which ensure energy savings, are: cellulose, fiberglass, foam insulation and mineral wool.

Below mentioned insulation manufacture companies are located in Latvia, as choice of locally produced materials is one of the factors that describes green architecture and helps to reduce costs by limiting transportation expenses. The only producer that is situated outside Latvia borders is Paroc Group, but due to its effective and innovative energy-efficient insulation solutions, leading position in the Baltic Sea region and relatively close location of production (Lithuania), it is included in the list with possible materials for low cost energy-efficient house.

Company name: Thermeko Ltd. TENAX EKOTEH RB&B ECO ISO RITOLS Paroc Group Table 4. Summary of insulation material qualities Thermal conducti Material Description vity λ (W/ mK) IZOPROK Environmentally 0,031 (porous friendly porous thermowool) thermowool formed in flakes or boards.

Material is very lightweight with good qualities of sound and thermal

Insulation material: IZOPROK-porous thermowool TENAPORS-expanded polystyrene Ecowool- cellulose wool Ecowool- cellulose wool Ecowool- cellulose wool Polyurethane foam PAROC-stone wool

Depth of material to reach U-value of 2 0,15 W/m \K (mm)

207

Embodied carbon (kgCO2e)

-

Price (per 3 1m )

≈60 EUR

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TENAPORS (expanded polystyrene EPS)

Ecowool (cellulose wool)

Polyurethane foam SPF

Stone wool

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insulation, fire safety, and durability as well as spread of insects and rodents.

Waterproof and lightweight (98% air and 2% polysturene) material made of polystyrene beads.

Material is ecofriendly and doesn’t accumulate bacteria.

Has no minimum content of recycled materials, but product can be recycled itself.

Economical and nontoxic material produced mainly from recycled paper with added natural salts.

Borax and borac acids ensure fire resistance and prevent buildings from destruction.

Prevents occurrence of decay and farmful fungi due to content of antipiren and antiseptic.

Provides no joint structure with relatively small thickness, but good insulating performances and high mechanical strength. Durable and fast to disseminate, does not settle and not attract insects.

Has minimum 5% content of recycled materials.

Basalt fiber based material with excellent sound absorption and fire resistance properties.

Contains at least 70% of recycled materials.

0,0330,043

220-287

15

≈88 EUR

0,0370,041

247-273

-1,9

≈24 EUR

0,0220,03

147-200

160

≈113 EUR

0,0330,04

220-267

38

≈692 EUR

Conclusion From table can be seen, that the most environmentally friendly material with high content of recyclable materials and low amount of carbon emissions during its manufacture process has cellulose wool. Ecowool is also the most produced 23

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insulation material among other eco-friendly products at the same time having lowest price. Cellulose insulation material has no surplus as it is blown directly into construction, which makes it highly economically efficient. IZOPOROK porous thermowool has better insulation properties, but its incomporation costs are twice as big as Ecowool. Polyurethane foam has the lowest rate of recycled material content as well as high price and biggest amount of carbon emissions during production time. Even this material has the lowest thermal conductivity factor, the negative factors mentioned above makes it less sufficient for the low cost single family house construction, giving priority to cellulose wool as the most suitable insulation material.

Thermal bridges Thermal bridge is a privileged heat path through the building envelope. Existence of thermal bridges in the construction influences surface temperature of building components, inside air temperature and total buildings energy consumption.

Additional transmission losses in the envelope can cause higher need for energy used for heating and cooling. Heat losses through the thermal bridges can be even higher than energy profit gained from the solar energy usage that would be enough to produce domestic hot water. Presence of thermal bridges can require up to 30% more energy needed for heating up the building. To mitigate negative effects of thermal bridges, geometry of the building should be kept simple with no interruptions in the insulation layer. If interruption cannot be prevented, insulation material should have high thermal resistance factor. When installing windows and doors, openings should have a contact with insulation layer.

Air tightness To keep the heat losses by air exchange as low as possible, building envelope must be constructed airtight-as an unbroken air barrier envelope around the construction, achieved by the use of correctly and properly installed vapour barrier. Latvian manufacture company Pro Clima offers vapour check, flexible tapes, seals and glues for air tight construction performance. To evaluate airtightness of the building blower door testing is applied. By depressurizing the building, a pressure gauge will measure the rate of airflow that is needed to maintain certain pressure differential.

Tight construction will present 5 to 6 ACH50 (air changes/hour at 50 Pa pressure), while construction with many leaks 20 or more ACH50.

Windows Properly installed windows can provide building with necessary amount of natural light, warmth and ventilation and can help to minimize heating, cooling and lighting costs. When selecting windows, factors as: frame, glass, design, installation and properties as: U-value, Solar Heat Gain Coefficient (SHGC), Visible Transmittance (VT) and Air Leakage (AL) should be taken into consideration. As Latvia has a heating-dominated climate, largest glazing areas should be arranged towards south, in order to gather heat gain in winter time, when the sun has low position.

Solar Heat Gain Coefficient (SHGC) in cold regions should be greater than 0,6 to provide more advanced solar heat transmittance, including possibility of winter solar 24

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heat gain. Visible Transmittance (VT) is an optical property indicating the amount of transmitted visible light. VT factor varies between 0 and 1 and includes the impact of frame, which excludes any visible light. To ensure good visible light transfer, windows should have a great VT factor. Air Leakage rating (AL) is indicated as the equivalent cubic feet of air passing through a square foot of window area. Reduced air leakage can be achieve by the use of awning (hinged at the top and open outward), casement (hinged at the sides) and hopper (hinged at the bottom and open inward) window types as the sash closes by pressing against the frame. Ufactor in cold climates should have a value of 0,40 or less to reduce conductive heat transfer. U-factor of windows is influenced by the type of frame, which can be manufactured from aluminium, wood, combination of wood and polymer, vinyl and fibreglass.

Table 5 Advantages of disadvantages of different window frames

Type of frame Properties

Aluminium frame +tight and strong construction +low need for maintenance +suitable for areas with high humidity -rapid heat conductivity

Wood frame +best insulation properties -highest demand on upkeep -might expand depending on weather conditions -susceptibility to rot

Wood/Poly mer frame +good thermal properties +moisture and decay resistance +must be prevented from water intrusion

Vinyl frame +high resistance to moisture +good energy efficiency measures +can achieve superior thermal performance -highest expansion coefficient

Fibreglass frame +dimensionally stable +good thermal performance +frame can be filled with insulation

Glazing or glass type has no less importance than frame material, when it comes to energy efficient house construction. Double glazed window with Low-E glass and vacuum-sealed argon fill is the most effective type of the window to maintain the best energy effective results and acquire cost savings.

Latvian window manufacture company “GLASKEK� produces windows with aluminium, vinyl, wooden and wooden/aluminium frames, offering different kind of glass coatings and types of glazing: solar, safety, with thermal/sound insulation and visibility properties.

Shading/Overhangs Additional appliances such as window treatments and coverings can be the way how to reduce energy consumption: reduce heat loss in winter and solar heat gain during summers. To minimize solar gain from windows positioned to the south, horizontal overhangs are more efficient, as the direct solar radiation has higher incidence angle. Incidence angle of direct solar radiation is lower in east and west, therefore in this case vertical overhangs are better to choose. Shading with glare relief can raise visual comfort of occupants, light coloured overhangs will diffuse daylight transmittance, but dark coloured-reduce the maximum amount of light.

Window treatments increasing energy-efficiency are:

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Awnings- able to reduce solar heat gain in summer time by 65% in windows positioned towards south and by 77% on west faced windows.

Blinds- are more effective in summer heat gain than winter heat loss reduction and can be divided into exterior and interior systems. Interior blinds are able to decrease heat gain up to 45%, while external blind systems can lower room temperature by around 10 degrees.

Draperies-should be kept close when room is getting direct sunlight during summer months and drawn during winter months to reduce heat loss. To achieve beneficial results, draperies should be positioned as close to window as possible.

Insulated panels-component consists of a rigid foam board insulation mounted on the interior part of the window. Panel is installed in a way that its edges are tightly sealed against window frame.

Mesh window screens-mounted on the exterior side of window frame and should cover all area of the window to diffuse solar radiation. This solution is effective on openings oriented towards east and west.

Overhangs-roof overhangs are having the highest effect on summer heat reduction of south-facing windows, allowing sunlight to penetrate windows during winter time at the same time allowing more warmth occur in the house.

Shades- should be positioned close to the window unit and have different colours of surface: white for heat reflection and dark-for heat abortion. Reflective coating should be always situated towards the warmest side, outwards during hot weather and inwards during colder months.

Shutters-can be located outside or inside the building and require a clear space to the one side of the opening. Shutters are showing the best results during summer, when appears the strong need for prevention of direct radiation.

Conclusion Building envelope will have effective structure and affordable construction price, if it’s design will be considered already at the design phase. The ratio of the outer surface area to enclosure volume of the house will be ≤1 and position on the plot will be oriented within 30° of South. Building construction will be built using aerated concrete blocks with timber roof structure, using cellulose wool as an insulation material. To maintain air tightness of the building that should present 5 to 6 ACH50, vapour barrier must be correctly and properly installed. Windows must be fixed with a contact with insulation layer in order to avoid thermal bridges. Position of windows should be arranged towards South and should be characterized with at least 0,6 SHGC, great VT factor and minimum U-factor of 0,4. To reduce heat loss during winter months and solar gain during warm seasons, shading appliances should be used, for example, draperies, blinds or overhangs.

Building services The amount of consumed electricity that was generated in Latvian territory in 2012 constituted 72%. In the same year 17,4% of total consumed energy was imported, defining increase in imported energy by 4% and in imported petroleum products by 26

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7,5%. To avoid expansion of needs for imported sources, lower amount of utilized energy and reduce environmental pollution, more advanced became an idea of renewable energy solution implementation. Renewable energy sources that are able to positively affect energy balance in Latvian conditions and meet all Directive 2012/27/EU requirements are: biomass, hydropower, natural gas, wind power and solar energy. In 2012 amount of energy gained by renewable sources reached 33,4% growth, which forms 66,6% of total generated energy and 55% of total consumed energy. Wood fuel and hydro resources were capable to cover 1/3 of total energy consumption.

Fig.5 Structure of primary resource supply and share of renewable sources

Heating Biomass boilers Biomass is classified as carbon-neutral renewable energy as during burning process biomass emits the same carbon dioxide amount as was absorbed while the wood was growing. Wood is the main fuel for domestic heating purposes and it can be formed into pellets, logs or wood chips. Heating for the whole building will require back boiler, which will not only produces heat, but also preheats the water. Biomass heating systems demand additional space for both: fuel storage and for unit itself, due to its physical parameters and need for systems occasional cleaning. The most advanced are automatic pellet stoves, which have 85-90% efficiency. The best fuel material for biomass boilers could be considered wood pellets, as they require less space for storage and are having higher energy content. Unlike others renewable energy systems that require only upfront investment, biomass heating has an ongoing fuel cost.

Fig.6 Final energy consumption in residential sector in Latvia, 2010

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In 2006 private home heating in 57% of cases was provided by wood boilers using wooden logs as a fuel, which is 1,5 times higher than in other Baltic states. As forests are covering 50% of Latvian territory, it gives a potential to biomass boiler usage, as system can be supplied with enough amount of local fuel. The most often biomass boilers used for single family house heating in Latvia have a capacity of 20kW, 30kW or 40kW. Comparison between different fuels (wood logs, wood chips and pellets) for the biomass boiler with capacity of 30 kW shows, that the amount of pellets necessary to reach certain amount of energy generation is twice less than amount of wooden logs, in addition it would cause 25% less emissions. Approximate price of Biomass boiler is 3100 EUR, if fuel (wood pellet) consumption measured in t/year is estimated as 20,4, it will cause additional 150 EUR per year for fuel supply.

GRANDEG Ltd. is Latvian company, which produces biomass boilers, with heat generation capacity of 25 kW, which is enough to provide with heating 150-250 m2 large house. MODERATOR Ltd. biomass boiler manufacture company offers boilers with heat capacity starting with 30 kW. Geothermal heating Geothermal heating and cooling takes advantage from fairly consistent during the year underground temperature, accumulated by absorbing 47% of solar energy. To gather underground thermal heat, complex uses pipe system, filled with water.

During water circulation in the loop, heat is getting exchanged between building, ground source heat pump and the earth, contributing highly efficient heating, cooling and hot water. System can be up to 400-600% efficient with ability to cut costs on current services by 80%. When heating is required, geothermal heat pump extracts heat from the ground by the use of earth loop that distributes heat in a state of air through a conventional duct system. The same energy can cover needs for domestic hot water heating and radiant floor system. To provide cooling, system extracts air from the inside of the building and moves it back to the earth loop or uses the warmth to preheat water. Loop types are horizontal, vertical and pond/lake, all of them belonging to the closed-loop system. Horizontal boreholes are having depth of 50-70m and cannot be closer to one another than 6 meters. Pipes for vertical loop system are placed at 1,2-1,5 m depth and should have a 1,2 m distance between pipes. Vertical loop system requires large ground area as to preheat 1m 2 of the building, 4 m2 of soil has to be used for pipe installation. If house is situated in urban area and has limited backyard area, horizontal loop is the most convenient.

In Latvian territory constant rock temperature can be found 20-25 m deep and has a value of 7-8째C. Due to seasonal fluctuations in the upper layers, which are found above 20-25 m depth rock temperature is higher in summers and gradually declines in colder months. Maximum temperature of water preheated by geothermal system can reach +55째C, therefore floor heating would provide higher efficiency than space heating by radiators. The costs for geothermal heating system installation that must be able to heat up 200 m2 large building using floor heating system and additionally preparing hot water in 300 l water heater can vary from 17 074 to 21 343 EUR (129 28

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259 – 161 577 DKK). Such size of the house requires heat pump with capacity of 12 kW and even installation expenses are greater than for other heating systems, it will pay for 4/5 of heating expenses of the entire remaining life. Geothermal system is independent from fuel sources, it doesn’t require additional space for fuel storage and special maintenance, can cover hot water needs, works completely automatic and has a service life of 30-40 year, even after that not requiring replacement of all system.

Geothermal heat pumps are not produced in Latvia, but there is wide variety of companies dealing with consultancy and geothermal system installation, for example, Vaillant Ltd., AVK-Energy For You, Energo Optimus, JUNKERS and NIBE. Natural gas heating Natural gas systems efficiency is ranging from 78 to 97% for forced air systems and 80 to 95% for hot water systems. There are free ways, how natural gas systems are heating up the space: by warm air, hot water or steam. In „forced air” system air is heated by natural gas burner until the temperature of 50-60 °C and distributed through the duct system with a blower or fan. During combustion process byproducts such as water vapor and carbon dioxide are produced and must be vented to the outer space. In hot water heating sytem water or steam is created in gas boiler and forwarded to pipes or tubes. This type allows to use radiators or pipes integrated in the floor structure and requires need for wall vents. It is beneficial to install highefficiency models in cold climates, as it will pay back in energy savings in a short time period. System connection to the underground pipeline will cost 156 EUR, Natural gas boiler price varies from 569 till 1281 EUR and room temperature controller from 52,25 to 165,44 EUR. As natural gas heatpumps are not manufactured in Latvia, heating solutions and installation can be provided by representatives of such companies as Ferroli, JUNKERS and Viessmann.

Conclusion Heating systems can be characerized by different aspects: ecological, technological, economical and comfort. The most ecological systems are having natural gas and biomass heating solutions. Technological advantages can provide electrical, natural gas and wood pellet heating sources, as they doesn’t require manual heating control and are able to work in automatic mode. Natural gas and electric sources doesn’t require space for fuel storage, which makes these systems even more advantageous, but also the most expensive heat sources. A high level of comfort can be reached by electrical, geothermal and natural gas systems, as usage os solid or liquid fules requires regular maintenace. The cheapest way to produce energy for heating would be achieved by use of biomass boiler. They are produced by Latvian companies, are having the lowest investment price and don’t require high fuel expenses.

Fig.7 Heat energy expenses using different heat 29 sources

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Ventilation Ventilation system is tightly connected to the energy efficient building systems, as it prevents heated and cooled air transmission through the air tight construction. There are three types of ventilation, natural, mechanical and mixed. To increase energy of the building, it is preferable to choose natural or mixed ventilation.

Natural ventilation Natural ventilation system moves air through the building using outside wind forces and pressure differences, providing both cooling and ventilation. Passive ventilation system maintains comfortable environment without installation of fans, use of mechanical systems for cooling and doesn’t require maintenance. Naturally ventilation systems are using up to 60% less energy, which can have a large effect on total energy use of the building. Passive system can front overheating and cold draught issues, which can be avoided by well-established stack effect, where warm air will rise and escape through the vents situated at the top of the building, cooling the space with air from openings. Cold draughts in winter can be avoided by keeping windows closed and mixing fresh cold air entering at the high level with pre-heated inside warm air. In order to maximise efficiency of wind driven ventilation, building should be located in windy area and oriented in a way that windward wall will be perpendicular to the summer wind. Natural ventilation design must ensure inlet and outlet openings in every room, positioned in opposing pressure zones, including one operable window for flow control. It is preferable to consider in building construction presence of skylights and ridge vents, minimum 3m ceiling height, installation of shading devices and sufficient use of surroundings.

Mixed ventilation Mixed ventilation system combines natural and mechanically controlled ventilation to achieve comfort cooling and improve inner air quality. Ventilation is operated by exhaust fans and operable windows, controlled manually or automatically. This type of ventilation is more suited for commercial and public buildings and can save up to 41% of energy. Disadvantages of current technology are related to complexity of the system, as it requires well cooperation between two different ventilation designs.

Mechanical ventilation Mechanical ventilation system distributes fresh air through the duct and fan system.

Benefits of mechanical ventilation can be represented in system’s ability to provide estimated and controlled amount of air flow, which comes from conveniently positioned intakes and exhausts. Depending on district ventilation can be divided into supply ventilation system for hot or mixed climates, exhaust ventilation system for cold climates and balanced ventilation, which is suitable for buildings in any location.

In balanced ventilation system both fresh air inlets and outlets are brought into use, which ensures equal quantity of supplied and exhausted air. Fresh air is supplied to living rooms and bedrooms and moist air removed from kitchens and bathrooms.

Disadvantages of mechanical ventilation system are maintenance, installation costs and noise, caused by the work of fans.

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Heat recover (MVHR) Mechanical ventilation with heat recovery is an air supply and extract system, that can re-use up to 95% of the stale air’s heat by replacing it with fresh and filtered warm air, which is afterwards transferred to the incoming air. MVHR consists of recovery unit and ducting structure supplied to every room. Recovery unit continuously extracts air from wet rooms and kitchens, recovers stale air with a use of heat exchanger and transfers outside. Fresh air coming from outside is drawn to the heat exchanger to be warmed and distributed to living rooms and bedrooms.

MVHR demands regular maintenance and control over balance of air supply and removal.

Conclusion The most efficient regarding construction costs ventilation system would be natural ventilation, as it doesn’t require installation of mechanical units and related fixtures, but will be able to achieve high indoor air quality. In order to maintain comfortable indoor environment, building construction must establish convenient stack effect and should be oriented perpendicular to the summer wind, as well as establish inlet and outlet openings in every room.

Hot water Solar thermal collectors Solar water heating is an energy-efficient way of producing domestic hot water with power of sunlight. Active indirect solar thermal system is more suitable for cold climates, as it warms cold water in heat-transfer unit using antifreeze preheated in collectors. Collectors are having 3 types: flat-plate collectors, integrated collector/storage systems and evacuated tube collectors. Solar thermal system can reduce utility bills up to 40-50% and reduces amount of greenhouse gases, but provides better energy saving results in buildings with higher hot water needs. Solar thermal systems contains different fixtures such as thermostats, sensors, controls and pumps to run the system properly, which causes high demands for installation work and subsequent maintenance. Solar hot water system has efficiency of 22%.

Research made by Institute of Physical Energetics (Riga, Latvia) proves that usage of solar water heating systems have a potential of achieving good results in Latvian climate, as it allows to use solar radiation approximately 1700-1900 hours per year, estimating the annual number of 100 cloudy days and 30 sunny days. The value of global radiaton towards horizontal surface in Riga (1109 kWst/m 2) is higher than in Berlin (1031 kWst/m2) and Copenhagen (1013 kWst/m2). Amount of produced energy varies during the year, depending on seasons, for example, from 1m 2 of solar collector it would be possible to generate 700-740 kWst/m2 (May-September), 200240 kWst/m2 (October-April) and 40-50 kWst/m2 (November-February). Solar thermal collector area of 5-6 m2 would be able to preheat hot water for family, consisting of 3 till 4 people. It would cover 70% of annual hot water consumption and as preparation of hot water occupies 10-20% of total amount of household costs, 31

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solar energy be an effective way how to acheive money savings. In Latvia the most efficient would be installation of evacuated tube collectors positioned at 45°, current system would provide with 418 kWh/m2 of energy per year. Costs of flat-plate collectors would represent 3090-3870 EUR (23 393- 29 298 DKK) without installation expenses.

Sun Invest Ltd. is company located in Latvia that produces systems for solar energy gain, including solar thermal collectors with a product name SELSOL. Solar Thermal and Biomass boilers Combination of both systems utilises the best in renewable and sustainable energy, providing energy saving solution that can offer both hot water supply and space heating. Solar coil transfers heat gained by the sunlight into the water storage tank, which uses the efficient energy generated by heat source-biomass boiler. When water in the thermal store is reaching necessary temperature for central heating and water supply, boiler gets a signal from thermostat to stop working process and forces independent pump to start delivery of water to the radiators and other appliances.

Combination of two energy efficient systems shows as good results, as each of them separately. Solar thermal collectors with area of 7,4m2 are able to produce 3093,2 kWh heat and biomass boiler 1316,8 kWh heat, that proves solar thermal collector ability to prepare 70,1% of needed domestic hot water amount.

Illumination Efficient lamps Lighting is responsible for 5% of a common household’s energy bill. The right choice of lighting tools can have a significant effect on energy savings, as energy efficient light bulbs are having benefit of 80% less usage of energy than incandescent bulbs.

Money savings are also obtained due to long lasting lifespan of efficient bulbs. The most popular of energy efficient lighting are compact fluorescent lamps (CFLs), lightemitting diodes (LEDs) and halogen incandescents. Even the costs for innovative bulbs are higher than standard incandescent ones, money savings will be achieved during a lifetime.

Energy-saving or halogen incandescent bulbs can last 3 times longer than traditional lighting.

Compact fluorescent lamps (CFLs) are miniature versions of full-sized fluorescents, they are 4 times more efficient and use up to 75% less energy than incandescents.

CFL can have even 10 times longer lifetime, as it consumes only about Âź of energy compared to standard bulb. CFLs are not preferable for use in places, where is a need for spot lighting or frequent on/off cycling, as well as outdoors, where bulbs must be covered or shaded as low temperatures can reduce light levels. Not all CFLs can be used with dimmers switches due to possibility of bulb lifespan shortening. One of CFLs lighting disadvantages is a small amount of mercury

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content, which is a toxic metal that can be released in case of broken ad disposed bulb.

Light-emitting diodes (LEDs) are small solid bulbs lasting up to 25 times longer than traditional incandescent bulbs and are even more energy efficient than CFLs as they contribute only 2-17 watts of electricity. LED light bulbs are long-lasting, durable, do not cause heating, are mercury-free and very cost-effective.

Energy can be saved also by the use of controls like motion detectors, twilight relays and light dimmers. Motion detectors, twilight relays and timer switches are responding to the movement and can be applied in passageways, hallways, utility rooms, stairs, basements and outdoors. Timer switches are capable to switch light off and on at pre-set time, which can be relevant in times, when building is left for an extended period. Light dimmers are giving an opportunity to adjust the light ungraduated to the certain level, without a need to switch light completely on/off or change the level of wattage.

Natural daylight Since the topic of energy efficiency of buildings gained worldwide attention, lighting issue became one of the possible aspects in energy saving realization. High proportion of natural light maintains environment good for health and productivity at the work place and at the same time can be a tool for reduction of running costs, if daylight autonomy is at the high level. Successful daylight system involves technologies, systems and architecture, including such components as exterior shading and control devices, glazing materials, aperture location, reflectance of room surfaces and electric lighting controls as well as consideration of buildings orientation and glazing relative to the sun path.

Windows can be organized into two categories regarding their functionality: to deliver daylight and to provide occupants with the view. Skylights are grouped into passive or active. Another type of toplighting appliances is a tubular daylight device that can transmit light from a lens at the roof to the lens at the ceiling plane through the tube with highly reflective coating on the interior. Lightshelves are the type of horizontal daylight reflection devices, which not only provides a glare control, but also redirects direct sun to the ceiling space in order to protect occupants from solar radiation. To achieve adequate energy savings, daylighting features must function in connection with daylight responsive electric lighting, which will turn off or blur electric lights in case of sufficient daylight illumination. Interior design is also a tool for successful daylight design creation. Typically the penetration of daylight should be two and a half time the distance between the top of window and the sill. Arrangement and design of furniture, interior finishes should be chosen in respect to daylight performance.

Photovoltaic systems Buildings energy costs can be decreased not only by controlling the need for electrical lighting, but also by the usage of sunlight in electricity production. One of electric power generation options is installation of photovoltaic cells, which directly 33

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converts sunlight into electricity. Electrical power accumulated by PVs can reduce electricity needs for refrigerators, washing machines, dryers, air conditioners and other large electricity consuming technologies. Photovoltaic panels should be placed in a way to receive the most sunlight-facing the South or oriented towards the sun’s position, when the need for electricity is at the highest level. For more effective electricity generation during shorter winter days, panels should be installed with a steeper slope bringing panels closer to perpendicular to the lower winter sun. For better maintenance PV systems shall be supplied with batteries, which will store energy in days with no direct sunlight. Modern photovoltaic cells can be produced from crystalline silicon or thin-film semiconductor material. Crystalline panels are more affected by the shading, therefore it is very important to locate panels in places, where possibility of shade is lowered until the minimum. The advantages of thin-film cells are lower market price, suitability to large applications and possibility to use various coatings and mounting systems.

As mentioned before, Latvia has as big potential in solar energy generation, receiving the most solar heat from March till September. Energy gathered during autumn, spring and winter covers only 10% from total energy amount produced during the year. There are two companies in Latvia Solar Invest Ltd. and Latkons that are producing photovoltaic panels, which technology is adjusted to Latvian climate. Solar panels are able to generate electricity even in cloudy, rainy or even sunny winter days, when temperature can drop to -20 degrees. In average PV system with power of 1kW can produce 900-1000 kWh/year, installation of unit with described characteristic will cost 5500 till 6000 EUR (42 000-45 000 DKK) including planning, all necessary fixtures and montage. Installation of current photovoltaic system can be paid back in 15 years. Due to high installation expenses, typically units with power of 1- 2 kW are chosen which will have an area of 10 m 2 and produced energy amount of 3-4 kW per day. Volume of generated energy can be applied for daily used appliances or electrical lighting, which doesn’t require as much energy as water heaters or other machines with high energy needs.

Conclusion To properly use illumination and therefore reduce energy costs, occupants should consider usage of light-emitting diodes (LEDs) for electrical lighting provision, preferably adding light dimmers and motion detectors, installed in hallways, staircases and utility rooms. The percentage of glazing surface related to the floor area should achieve 20%, in order to provide occupants with decent amount of natural lighting. Additionally should be considered penetration of daylight and position of furniture in order to intensify daylight effect. Usage of sunlight for electricity generation won’t be suggested for low-cost house construction. Even solar energy costs are relatively low, such system is unpredictable and depends on seasonal changes and will require high investments for equipment purchase and installation.

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Finances National Reform Programme states different barriers towards energy efficiency implementation. Among these factors financial problems are mentioned as well. High interest rates in commercial banks and already before made loan obligations interfere with ability to apply for new obligations or obtain a loan from the bank.

Possible solutions to promote sustainable building design would be entrustment of project development to professionals and attraction of European funds or other sources for financial support, for example: European Bank for Reconstruction and Development was founded to support projects that develop sustainability and energy efficiency. The EBRD focuses on Eastern Bloc countries and funds up to 35% of the total project costs, it helps to finance smaller projects by supporting local commercial banks, micro-business banks, equity funds and leasing facilities.

Rotary Fund supports and finances only the projects that can provide repayment of funds in certain period of time. Rotary fund is based on finances provided by the State and local municipalities, donor institutions and European Union aid. According to Reform Programme, National Energy Efficiency Fund will be established to support projects that will help to fulfil requirements of Directive 2012/27/EU. Climate Change Financial Instrument is Latvian government budget program providing projects with necessary finances, formed by Proceeds of the Assigned Amount Units Purchase Agreements. Some of the projects financed by current programme in relation to single family sector are: Low energy housing and Renewable energy use in household sector (microgeneration).

In case of citizen disinterest in energy efficient house building, Latvian government is planning to establish loans with reduced interest rate or possibility of loan principal cancellation if the project will ensure certain level of energy savings.

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Conclusion The National Reform Programme states that only 3% (by number) and 5% (by area) of the buildings build after 2003 fulfils energy requirements declared in LBN 002-01 “Thermal engineering of building envelope�. It can be explained not only by imperfections made during design and execution stage, but also with relatively low Building Regulation influence on client choice regarding implementation of sustainable solutions in house construction. At the moment the only restrictions are issued regarding U-value number of different building components. Location in temperate climate zone demands sufficient choice of building insulation material and heating system, knowing that there are more heating degree days than on average in Europe. High global radiation factor insists building position in a way that long side will face the south, avoiding space overheat by use of shading appliances.

To build energy efficient single family house, use of expensive and innovative materials is not required. Competent building envelope can be reached by use of traditional and cheap construction materials that presents low thermal conductivity factor, for example, aerated concrete blocks and cellulose wool, if only existence of thermal bridges will be prevented and vapour barrier will be used in order to obtain airtightness. Openings will not cause energy losses until the component will be installed correctly. In this case choice of window might be not so significant, as all types are able to meet high standards. Decision on window type depends more on how much occupants are ready to spend on frame upkeep. Expenses can be further reduced by supplied natural ventilation system and installation of biomass boiler for space and domestic water heating, using wooden pellets as a fuel. These systems will not require high installation costs and enormous investments, providing high efficiency and comfort.

Energy efficient housing concept is unfairly considered as a very expensive and unaffordable for an average citizen. Sustainable building requires high quality of execution works and is demanding very well made analysis on daylight, shading and position on site already at the design phase. These investigations will not cause additional investments, but will only lead to energy savings during occupancy period.

Lack of information about sustainable solutions keeps clients away from low energy consuming house construction, which not only could positively affect well-being, but also could receive financial support from different European funds and government budget programs.

While writing the dissertation, I gained a lot of new information about technologies helping to lower energy consumption of buildings. Results are proving that sustainability is affordable and hopefully this research will encourage readers to consider usage of more efficient solutions for home constructions, at the same time supporting local manufactures and making a step towards cleaner environment.

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List of references List of electronic sources

Climate Change 2007: Synthesis Report http://www.ipcc.ch/pdf/assessment-report/ar4/syr/ar4_syr.pdf EU ENERGY IN FIGURES 2010. CO2 Emissions by Sector http://ec.europa.eu/energy/publications/doc/statistics/ext_co2_emissions_by_sector. pdf Buildings and Climate Change http://www.unep.org/sbci/pdfs/SBCI-BCCSummary.pdf LBN 002-01 Thermal engineering of building envelope http://likumi.lv/doc.php?id=56049LBN 003-01 Construction Climatology http://likumi.lv/doc.php?id=53424 LBN 209-09 Low-rise residential buildings http://likumi.lv/doc.php?id=197624 LBN 231-03 Heating and ventilation in residential and public buildings http://likumi.lv/doc.php?id=79290 General Construction Regulations http://likumi.lv/doc.php?id=269069 Building Law http://likumi.lv/doc.php?id=36531 Calculation method of building energy performance http://likumi.lv/doc.php?id=187240 Building energy certification rules http://likumi.lv/doc.php?id=253635 Energy Efficient Buildings Strategy http://ec.europa.eu/energy/efficiency/eed/doc/article4/2014_article4_lv_latvia.pdf Directive 2012/27/EU of The European Parliament and of The Council http://eurlex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:2012:315:0001:0056:EN:PDF Energy Efficiency Policies and Measures in Latvia http://www.odyssee-mure.eu/publications/national-reports/energy-efficiencylatvia.pdf Energy efficiency http://www.europarl.europa.eu/ftu/pdf/lv/FTU_5.7.3.pdf Energy Efficiency in Europe-Assesment of Energy Efficiency Action Plans and Policies in EU Member States. Latvia http://www.energy-efficiencywatch.org/fileadmin/eew_documents/Documents/EEW2/Latvia.pdf Summary of the project recommendations of the ASIEPI project

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http://www.buildup.eu/sites/default/files/content/P191_Summary_of_the_recommend ations_ASIEPI.pdf Research of renewable energy source usage in Latvia http://www.bf.rtu.lv/documents/sgut/leb.pdf Solar energy usage potential in Latvia http://www.lasa.lv/KPFI/Semin/2_Sipkovs.pdf Use of geothermal heat pumps for building heating systems http://bef.lv/fileadmin/media/Publikacijas_Klimats/2011_Kastaniitis_publikacija.pdf Renewable energy in Latvia http://www.lza.lv/images/stories/Pasakumi/AER%20nozime%20Latvijas%20pasvaldi bu%20un%20valsts%20attistiba.pdf Use of biomass in energy generation, monitoring http://www.e-koks.lv/files/Biomasa_projekts_2012.pdf Use of biomass, Sustainability criteria application and measure development http://www.lvaf.gov.lv/faili/petijumi/Biomasas_izmantosana.pdf Biomass heating: a guide to feasibility studies http://www.biomassenergycentre.org.uk/pls/portal/docs/PAGE/BEC_TECHNICAL/BE ST%20PRACTICE/38215_FOR_BIOMASS_3_LR.PDF Modelling and analyses of heating solutions for individual buildings http://llufb.llu.lv/dissertation-summary/agriculturalengineering/Raimunds_Selegovskis_l-a.pdf Daylight: an Energy Saving Resource http://www.kevanshaw.com/ksld_upload/pdf/Shaw_Daylight_Energy_Saving_Resource.pdf Buyer’s Guide. Natural Gas Heating System http://www.citizensenergygroup.com/pdf/ProductGuides/furnaces.pdf Mechanical Ventilation. Breathe Easy with Fresh Air in the Home http://www.energystar.gov/ia/new_homes/features/MechVent_062906.pdf Passivent. Mixed mode cooling systems http://www.passivent.com/downloads/mixed_mode_brochure.pdf

http://www.buildup.eu/publications/32236 http://en.wikipedia.org/wiki/European_Bank_for_Reconstruction_and_Development http://www.meteo.lv/lapas/vide/klimata-parmainas/latvijas-klimats/latvijasklimats?id=1199&nid=562 http://www.lotwa-latvia.pl/index.php?lang=0&cPath=1&txt_id=7 http://www.abc.lv/?template=abc_raksts&article=ilgtspejigu_majoklu_buvniecibas_ie spejas http://en.wikipedia.org/wiki/Green_building http://www.makroekonomika.lv/latvija-rupnieciba-ir http://www.tirailatvijai.lv/raksts/165650 http://www.autoavize.lv/index.php?n=586&a=1633

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http://greenhomeguide.com/know-how/article/choosing-the-best-insulation-deliversenergy-savings http://www.tavamaja.lv http://www.ritols.lv/siltumizolacija.php http://tenapors.lv http://www.rbb.lv/ekovate/home.php?lang=en&page=about&table=ekovate_ekovate http://greenhomeguide.com/know-how/article/choosing-the-best-insulation-deliversenergy-savings http://www.superhomes.org.uk/resources/whats-best-insulation-material/ http://www.isover.com/Q-A/Green-facts-energy-efficiency/How-to-design-and-buildan-energy-efficient-building http://www.buildup.eu/links/36160 http://www.thermopedia.com/content/603/ http://nesa1.uni-siegen.de/wwwextern/idea/keytopic/3.htm http://passiv.de/former_conferences/Passive_House_E/energybalance.html http://www.newlearn.info/packages/clear/thermal/buildings/configuration/surcafeareato_vol_ratio.ht ml http://www.buildingscience.com/documents/insights/bsi-061-function-form-buildingshape-and-energy http://www.architecture.com/RIBA/Aboutus/SustainabilityHub/Designstrategies/Earth/ 1-1-3-2-Buildingorientation.aspx https://www.archsd.gov.hk/archsd/html/teachingkits/TK1/energy_efficiency_conserva tion.html http://www.decosoup.com/knowhow/1124-solar-orientation-and-room-layout http://www.asiepi.eu/wp-5-airtightness.html http://www.greenbuildingstore.co.uk/page--airtightness-in-buildings.html http://www.artiva.lv/produkti/sistema http://www.energyconservatory.com/sites/default/files/documents/blowerdoortestingjl c.pdf http://energy.gov/energysaver/articles/energy-efficient-windows http://www.hgtvremodels.com/interiors/choosing-energy-efficient-windows-for-yourhome/index.html https://ortus.rtu.lv/science/lv/publications/13879 http://energy.gov/energysaver/articles/window-types http://www.shadefactor.com.au/energy-efficiency/sunshading-and-energy-efficiency http://energy.gov/energysaver/articles/energy-efficient-window-treatments http://www.energywise.govt.nz/your-home/lighting/savings http://energy.gov/energysaver/articles/tips-lighting http://eartheasy.com/live_energyeff_lighting.htm http://www.wbdg.org/resources/daylighting.php http://photovoltaics.sustainablesources.com http://www.seia.org/policy/solar-technology/photovoltaic-solar-electric http://www.yourhome.gov.au/energy/photovoltaic-systems 39

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http://sinergo.lv/potencials/ http://www.ntz.lv/dazadi/solaras-sistemas-3-iespeja-pasiem-iegut-elektribu-unsiltumu/ http://www.baxi.co.uk/renewables/biomass.htm http://www.yougen.co.uk/renewable-energy/Biomass+Boilers/ http://www.climatemaster.com/residential/how-geothermal-works/ http://www.waterfurnace.com/how-it-works.aspx http://energy.gov/energysaver/articles/geothermal-heat-pumps http://www.aga.org/Kc/resourcesbydiscipline/comm/prtips/Pages/NaturalGasHeating Systems.aspx http://www.aprilaire.com/whole-house-products/whole-house-products/ventilation http://www.breathingbuildings.com/products/natural-ventilation-explained http://gbtech.emsd.gov.hk/english/utilize/natural.html http://sustainabilityworkshop.autodesk.com/buildings/natural-ventilation http://www.buildingscience.com/documents/guides-and-manuals/gm-reviewresidential-ventilation-technologies http://www.cbe.berkeley.edu/mixedmode/aboutmm.html http://www.build.com.au/mixed-mode-hybrid-ventilation http://www.admsystems.co.uk/index.php/products-9/heat-recovery-menu/heatrecovery-ventilation-system http://www.channel4.com/4homes/diy/plumbing-heating/heat-recovery-ventilationsystems http://sunwatersolar.com/solar-thermal/what-is-solar-thermal http://www.energydepot.com/RPUres/library/Swaterheater.asp http://www.southface.org/learning-center/library/solar-resources/how-solar-thermalworks http://www.waxmanrenewables.co.uk/intergrated-how-it-works.htm http://www.7energy.co.uk/solar-thermal/solar_complete_heating.html http://www.videsvestis.lv/content.asp?ID=113&what=62 http://www.aeroc.lv/index.php?page=783&lang=lat&cnt=AEROC_EcoTerm_Plus http://www.lode.lv/lv/produkti/mala-celtniecibas-bloki-keraterm/ http://www.kollebeton.lv/lv/production/sienas-materiali/keramzitbetona-bloki/ http://www.buvema.lv/lv/production/2/4/ http://www.tavamaja.lv/buvmaterialu-razotaji/bloki.html http://building.lv/news/361-buvejam-maju/83882-latvija-popularakie-privatmaju-sienuveidi http://www.selsol.lv http://www.ipprojekts.lv/?cat=1&lang=lv http://www.lg.lv/index.php?id=221 http://www.glaskek.lv http://www.ekoiso.com/lv/ http://thermeko.lv/lv/products/details/32 http://www.superhomes.org.uk/resources/whats-best-insulation-material/ 40

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http://home.howstuffworks.com/home-improvement/construction/green/10-cuttingedge-building-materials.htm#page=0 http://www.quickenloans.com/blog/hottest-2014-building-materials-energyefficientsustainable http://www.countrysidemag.com/84-3/countryside_staff/

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List of figures

Fig.1 Global annual emissions of anthropogenic GhGs from 1970 to 2004 (Climate Change 2007: Synthesis Report, page 14) Fig.2 CO2 Emissions in Eurpean Union in 2007 (EU ENERGY IN FIGURES 2010. CO2 Emissions by Sector, page 30) Fig.3 Impact of building shape on annual heating energy for a small 144 m 2 (1500 ft2) building in a coldclimate. (http://www.buildingscience.com/documents/insights/bsi-061-function-form-buildingshape-and-energy) Fig.4 Room layout according cardinals (http://www.decosoup.com/knowhow/1124-solar-orientation-and-room-layout) Fig.5 Structure of primary resource supply and share of renewable sources (Solar energy usage potential in Latvia, page 2) Fig.6 Final energy consumption in residential sector in Latvia, 2010 (Energy Efficiency Policies and Measures in Latvia, page 25) Fig.7 Heat energy expenses using different heat sources (Modelling and analyses of heating solutions for individual buildings, page 50) Table1. U-value requirements for building envelope in residential buildings and energy consumption value in different time periods, including current demands (Energy Efficient Buildings Strategy, page 12) Table 2. Dynamics of built houses in Latvia (http://www.abc.lv/?template=abc_raksts&article=ilgtspejigu_majoklu_buvniecibas_ie spejas)

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