Final presentation to ackbuilders 11 08 12

Re-­‐Framing the House: An Energy Perspec9ve Presented by Tom Barnes, Principal

Nantucket Building Science Email: buildingscience.ack@gmail.com Tom cell: (508) 631-­‐6633

The Long Explana9on…

Wikipedia says Building Science is….

•

Building science is the collec/on of scien/fic knowledge that focuses on the analysis and control of the physical phenomena affec/ng buildings. It tradi/onally includes the detailed analysis of building materials and building envelope systems.

•

The prac/cal purpose of building science is to provide predic9ve capability to op9mize building performance and understand or prevent building failures.

The building science of a project refers to strategies implemented in the general and specific arrangement of building materials and component-­‐assemblies.

This is the architectural-­‐engineering-­‐construc9on (AEC) technology discipline that concerns itself with the 'mainly detail-­‐design' of buildings in response to naturally occurring physical phenomenon such as: – weather (sun, wind, rain, temperature, humidity), and related issues (e.g. freeze/thaw cycles, dew point/frost point, snow load & driX predic9on, lightning paYerns etc.)

– subterranean condi/ons including (poten9al for soil + ground-­‐water ac9vity, frost penetra9on etc.).

– characteris/cs of materials (e.g. Galvanic corrosion between dissimilar metals, permeability of materials to water and water vapor, construct-­‐ability, compa9bility, material-­‐adjacency and longevity issues).

– characteris/cs of physics, chemistry and biology such as capillary-­‐ac9on, absorp9on, condensa9on (“Will the dew point occur at a good or bad place within the wall?"), gravity, thermal migra9on/ transfer (conduc9vity, radia9on and convec9on), vapor pressure dynamics, chemical reac9ons (incl. combus9on process), adhesion/cohesion, fric9on, duc9lity, elas9city, and also the physiology of fungus/mold.

– human physiology (comfort, sensory reac9on, radiance percep9on, sweat func9on, chemical sensi9vity etc.)

– energy consump/on, environmental control-­‐ability, building maintenance considera/ons, longevity/sustainability, and occupant (physical) comfort/health.

• •

Energy, Building Science, Perspec9ve (Opera9onal Defini9ons, etc)

Short Explana9on: Building Science = – the detailed analysis of building materials and building envelope systems – that offers a predic/ve capability to op/mize building performance – and understand or prevent building failures We are talking mostly about: • Energy =measurable quan9ty of heat, work, or light • The common denominator for this is: BTU (Bri9sh Thermal Unit -­‐ common conversion unit) – energy to raise one pound of water by 1 degree F.

On Nantucket, our fuel choices have embedded amounts of BTUs in them….

Ack fuels -­‐ BTU Equivalents: • LP gas – 92,000 BTUs per gallon • #2 Fuel Oil – 139,000 BTUs per gallon • Electricity – 3,412 BTUs per 1000 waSs (kW) Sample House: • Typical Exis9ng Ack house – 3,000 SF = 110,000,000 BTU per year • 40 years/20% improvement = 880,000,00 BTUs – a builder/ designers poten9al long term impact! Equals 8 years of energy.

Habitat Home (LEED Silver): • Scored a 51 on HERS score; super 9ght construc9on (ICF), solar thermal system • Expected Annual BTUs consump9on = 22,000,000! 80% beYer.

What are Frameworks? They include government prescribed (codes), voluntary programs, and best prac/ces (norms, standards)

• Building codes • Energy codes (IECC 2009, 2012) • Leading edge ini/a/ves (MA Green Communi9es) • U/lity Programs (MassSave) • Voluntary Programs (LEED, Energy Star for Homes – aka E*Homes) • Best prac/ces (Ack)

Frameworks Â

“Drivers” of These Frameworks • The Building Science informs the codes; health and safety concerns drive the codes • Codes drive the majority of choices and behaviors: design, construc9on • Government ini9a9ves drive changes too: Green Communi9es Act, Stretch Code (MA), EPA E* • U9lity regulatory frameworks drive programs – MassSave – DSM (reduce peak loads) • Voluntary programs drive some behaviors – LEED, MA New Homes w/ E*

The “Energy”Frameworks -­‐ MA • Building Code, Energy Code (IECC 2009, 2012) – Primary tools: ResCheck (GIGO), insula9on inspec9ons, HVAC “duct blaster” tes9ng, reliance on subcontractors

• “Stretch Energy Code” Communi9es – Primary tools: TBC – Thermal Bypass Checklist (prescrip9ve), HERS ra9ngs/inspectors, Blower Door Tes9ng, Duct Tes9ng, Manual J (load) calcula9ons

• Voluntary programs: MA New Homes w/ E*, LEED for Homes • ASHRAE 62.2 (ven9la9on)

Illustrates How Many Communi9es Have Adopted The Stretch Code Framework

More Than 122 Communities Have Voluntarily Adopted “Stretch Code in Mass (so far!). And There are Financial Incentives • Almost the same as the Stretch Code – Approx 30% in 2010 of new homes in MA

• Builder incentives/rebates – $750 - $8000 for SFD – $350 - $4,000 for MF

• Additional – Appliances – up to $100 – Heating – up to $1,500 – Cooling – up to $500 – Lighting – free

The New Energy Code is Coming!

2012 IECC (July 1, 2013) -­‐ Highlights • Ceiling R-­‐Values – R-­‐49 from R-­‐38! However, an alterna9ve “overall assembly U-­‐value” calc of 0.026 (R of 38.46) can be submiYed as an alterna9ve. Also an overall “building” UA alterna9ve can also allow one to design around this R-­‐49 – HERS modeling and Manual J can do these calcula9ons for inspectors. There may be other “work-­‐arounds” for this.

• Mandatory “Cer9ficate” near electric panel – info on insula9on, doors, windows, duct system leakage test results, blower door test results, hea9ng/cooling/DHW efficiencies = essen9ally an Owner’s Manual (a best prac9ce?)

2012 IECC (July 1, 2013) Further Highlights • Floor insula9on shall be installed to maintain permanent contact with underside of subfloor decking.

• Sealing of breaks in the air barriers – more and 9ghter sealing of cracks, gaps, and pathways for air.

• R402.4 Air Leakage (Mandatory) – BD tests required – no more than 3 ACH50! Tes9ng done aXer all penetra9ons to thermal envelope (recommend pre-­‐ drywall!)

• R403.2.2 (Duct) Sealing (Mandatory), Tes9ng – Post-­‐ construc9on – max 4% of CFA leakage. (4/3 for rough in tes9ng.) NA if ducts, equipment inside envelope.

2012 IECC (July 1, 2013) Even More Highlights • R403.6 – Equipment Sizing (Mandatory) – Hea9ng and Cooling Equipment shall be sized per ACCA Manual S from loads calculated from Manual J (sizing soXware.) (HERS RemRate soXware and Manual J do some of the same things as far as load calcula9ons.)

• R404.1 Ligh9ng Equipment (Mandatory) – 75% high-­‐ efficacy lamps.

• R405 – Simulated Performance Alterna9ve – (HERS ra9ng, RemRate model) – PERFORMANCE vs.

PRESCRIPTIVE path) – proposed design is shown to have a lower energy than a standard reference design. Checklist for inspector required to verify in field.

Primary Tools in the Frameworks/Codes – Energy SoXware ResCheck

Manual J

HERS (RemRate)

Inputs

Building specs

Building specs

Building specs

Outputs

Report for submission for permit

Load calcs and 2012 HERS score and 120 IECC info needed more pages of for permit analysis

Uses

Code compliance/ permit

Load calcula9ons, equip sizing, code compliance

Bonus Uses

?

Tradeoffs analysis – Tradeoffs analysis – what ifs; UA path; what ifs; UA Path; Sales tool Sales tool

Piyalls

GIGO; used to pull a GIGO if done for permit; builder or “free” by supply designer calcs it house, oversized

Standardized scoring system, Load calcula9ons

GIGO if details not accurate

On to the Building Science

Principle Focus #1: Gradients • Temperature – from hot to cold (think conduc9on) • Moisture – moves from wet to dry • Pressure – from high to low • Don’t try to change the laws of physics – work to minimize the impacts of each on a home

Note in this diagram that water molecules are smaller than air molecules thus allowing them to “diffuse” through walls and founda9ons and roofs….

Going Against The Gradient Takes Energy – The Basics of Heat Movement and the Physics of “Phase Changes”

Principle Focus #2: Building Shell Heat Flow • Goal: Design Building Shells to minimize unwanted heat flow, moisture flow, pressure differen9als (control the gradients!)

• 2 mechanisms (how heat moves): transmission and air leakage (which takes moisture/water molecules with it!)

• 2 factors in transmission piece: thermal resistance (R) and surface area (A) – more heat needed for larger surface area • Temperature gradient (between inside and outside) drives transmission “flow” – when it’s colder outside, heat loss increases as flow increases!

• Insula9on resists conduc9on (slowest means of heat flow), convec9on, radia9on through a building component. IR camera can detect and “photograph” radia9on.

• Air leakage measured by Blower Door (see AckBS form)

R Values of Assemblies: R means “resistance” to heat transmission/flow; higher R usually beYer

Note: R-­‐values is “addi9ve” – add more layers, increase R-­‐value)

Cavity insula9on forces conduc9on over radia9on and convec9on – conduc9on being the slowest method of transmission

From Raw Data to Results – Calcula9ng “Loads”, Sizing Equipment • Raw data: site data (orienta9on), surface area calcula9ons (walls, floors, ceilings) • R – Values by component or area (e.g. R-­‐19 in walls, R-­‐30 in floors, R-­‐38 ceilings). Door and window areas and characteris9cs.

• Air leakage from blower door test • Load calcula9on soXware (Man J, HERS RemRate) • Hea9ng/Cooling equipment op9ons and efficiencies • Output – BTUH – amount of heat to move mechanically (refrigera9on cycle)

•

•

Load – how many BTUs per hour (BTUH) needed to be added (hea9ng) or removed (cooling) to provide comfort.

Cooling load also involves removal of moisture content (latent heat)

Boiler Ra9ng Needed

Loads Sub-­‐Part #1: Insula9on Insula/on Type/Descrip/on

R-­‐Value/inch

Fiberglass baYs

3.1 (cavi9es)

Dense pack cellulose

3.5

Low density spray foam (OC)

3.6 (Icynene)

High density spray foam (CC)

6.0

XPS (extruded polystyrene)

5.0 (blue, pink)

Polyisocyanurate

6.8 (foil faced)

Now, compare these to code requirements, best prac9ces for uses.

R-­‐49 ceiling/roof = 8.2 inches closed cell spray foam, 13.6 inches with open cell spray foam Fiberglass baYs are not an air barrier!

Loads Sub-­‐Part #2: Air Leakage • There is no “perfectly air 9ght” home nor should there be.

• There are code driven standards – engineered standards – for ven9la9on, which is 9ed to leakage.

• Go below certain thresholds (0.35 ACHn), add mechanical ven9la9on – exhaust only bath fans are preferred method, best prac9ce at this 9me. ERV is another alterna9ve.

• EE programs prescribe air sealing limits (SIR)

Blower Door Samples - Actuals

Actual Formula Blower Door Variable Readings (tested)

Actual Volume

Formula Variable

(Calculated)

CFM50

60

Volume (CF)

n

Results (Calculated) 5-7 range = good

Results (Converted) Below 0.35 = mech vent req'd

ACH50

ACHn

Sample Tested House: "Tight" Habitat Pochick Ave house 8/3/12 1 story cape, move on, rehab

ACH50 ACHn

645 645

60 60

11960 11960

NA 16.7

3.236

Sample Tested House: "Tight" Hooper Farm Rd 2 story cape, modular

ACH50 ACHn

1333 1333

60 60

14903 14903

NA 13.3

5.367

Sample Tested House: "Leaky" Sunset Hill Lane 1.5 story, garage apartment

ACH50 ACHn

722 722

60 60

5250 5250

NA 15

8.251 leaky

0.550

Sample Tested House: "Leaky" Sunset Hill Main House 1 story home

ACH50 ACHn

3672 3672

60 60

19000 19000

NA 16.7

11.596 leaky

0.694

Reduction 1,821 2,089 1,821 2,376

Percentage 50% 57% 50% 65%

Variable 0.35 5.00 0.35 0.70

Req'd CFMn 110.833 94.810 110.833 77.583

Sunset Hill Main House CFM50 Air Sealing Opportunities: Standard BD Target: Get to 0.35 ACHn ASHRAE 1,851 5 ACH50 target E* Homes 1,583 BPI High 1,851 70% of ASHRAE BPI Low 1,296

0.194

0.404

Real Volumes/CFMs

38700 2317 4186 Yes

CF/hr @50p CF/hr @nat ASHRAE CF/hr @nat standard Needs Mechanical Ventilation?

79980 6014 5216.05 No

CF/hr @50p CF/hr @nat ASHRAE CF/hr @nat standard Needs Mechanical Ventilation?

43320 2888 1837.5 No

CF/hr @50p CF/hr @nat ASHRAE CF/hr @nat standard Needs Mechanical Ventilation?

220320 13193 6650 No

CF/hr @50p CF/hr @nat ASHRAE CF/hr @nat standard Needs Mechanical Ventilation?

BD reading @ ASHRAE CFM50 Standard BD reading - E* Homes CFM50 Standard BD reading - BPI CFM50 Standard - "BAS" BD reading - BPI CFM50 70% of BAS

Using a Blower Door and proven air sealing techniques we can air seal this leaky building down to this CFM measurement and reduce air leakage by 50%!

Demys9fying the Blower Door • Of these 4 houses, one was 9ght and requires mechanical ven9la9on – it has an ERV • The second one – on Hooper Farm Rd – was spot on….5.36 ACH50 (range of 5-­‐7 is considered good) • The last one could benefit from air sealing – 11.59 ACH50. BD reading was 3,672 CFM50 – Op9mal would be to seal it to reduce this to 1,851 CFM50 – a 50% reduc9on.

• House volume is 19,000 CF; 13,193 CF naturally turns over in this house each hour – 70%! That’s heat out the door.

Blower Door, Duct Blaster (HVAC)

Duct Blaster Principles

HVAC Duct Tes9ng (sample handout provided) • Duct leakage can account for a significant por9on of energy losses in a home (25%+) • In the current energy code and being enforced on Ack – HVAC subcontractors have to test for leakage • Sample home (Hooper Farm) – passed 2009 IECC limit of 8% of CFA (post construc9on ,leakage to outside test). (Note: 2012 IECC calls for 4% of CFA leakage – a 50% performance improvement.)

• Best prac9ces are to have all equipment and ducts inside the thermal boundary (not in uncondi9oned basements or a{cs)

This is considered the best prac9ce: Ducts fully inside the thermal boundary leak to the inside so do not have to be tested under 2012 IECC codes as heat lost from ducts is s9ll inside the “thermal envelope” or the heated/cooled area of the building.

Domes9c Hot Water Ligh9ng and Appliances, Plumbing Windows, Doors, Openings • Domes9c hot water – use high efficiency systems, on demand (op9mal for seasonal home?)

• Ligh9ng – CFL’s maYer, quality improving. Halogens are energy sinks! Use E* fixtures.

• Appliances – E* labeled will do it!

• Plumbing – use WaterSense labeled devices (EPA cer9fied) • Windows and doors are your energy “weakest link.” Use E* windows, well insulated doors, storm doors. Build ves9bule at boYom of bulkhead entries. Air seal properly around all areas.

Energy Efficiency, Conserva9on • Energy Efficiency (EE) – do more with the same energy • Conserva9on – use less energy, turn down heat • MassSave (Cape Light Compact on MV, Cape) – they implement all EE programs for Ack) • Please arrange a free home energy assessment form MassSave – or contact Nantucket Building Science to help you. Having an audit also qualifies you for a 0% interest, 7 year “Heat Loan Program” for EE upgrades, new equipment, etc.)

Alterna9ve Energy Systems • Energy efficiency (EE) is the “5th fuel” – improve structures first, reduce overall load • We have helped evaluate, source, and install several systems on island to date • Disincen9ves to AltE – cost, HDC, maintenance • Financial incen9ves to AltE – Federal, state • Market drivers ques9onable on Ack • Order of Effec9veness (AckBS opinion): – – – – –

Solar Thermal (installed a few of these, maintenance concerns) Solar PV (recent price drop, great incen9ves) Air source heat pump (e.g. Mitsubishi mini-­‐split) Ground source heat pump (geothermal) Wind (big turbines, not small ones)

Business, Money, Incen9ves • There are Federal, State, U9lity, and Other program financial incen9ves out there.

Incen9ve samples

Incen9ve samples

Incen9ve samples

Best Prac9ces for Ack: • Reduce thermal bridging – advanced framing methods • All ducts within condi9oned space – plan in advance • Durability – keep water out, control air flow, promote drying • Performance Tes9ng – IECC 2012 – ducts, air leakage • Commissioning – Mechanical Equipment – ensure proper opera9on • Basements, Founda9ons, and Slabs – see next slide (detailed) • Control Air Leakage • Windows, doors – install E*, properly, air sealed, panned • SEER of 15 and higher for AC • AFUE for furnaces and boilers above 90% • Manual J for HVAC sizing (loads); Duct sizing per Manual D • Power ven9ng all combus9on appliances • Indoor humidity – 60% summer; 40% winter • No plumbing, ducts in exterior walls if possible • Owner’s manual and training

Best Prac9ces -­‐ Basements • Note points where sealants are used • Note capillary ac9on through founda9on, slab • Note slab poured on crushed stone – never sand; poly under slab on top of stone • GuYers, downspouts not shown but are cri9cal for bulk moisture removal • Moisture dries to inside – do not use vapor barriers

Air Barrier Details – Air

barriers are cri9cal and part of the code. Typically, the taped drywall inside the house is a primary air barrier – a barrier to the uncontrolled, free flow of air across the thermal shell/ wall/floor/ceiling. Free flowing air traveling through cracks, leaks, and penetra9ons/holes leads to moisture and energy flow, poten9al problems and higher energy bills. It is rela9vely easy to get these details right – lots of 100% silicone caulking!

We’re Done! For now….

Please sign in and give us your email to get this PDF sent to you.

Call us if you need diagnos9c tes9ng, help with codes, specs, diagrams, best prac9ces, problems with mold…whatever.

Buildingscience.ack@gmail.com Tom Barnes cell 508-­‐631-­‐6633

Bonus Slides

Rela9ve Humidity Explained

The rela/onship between temperature and humidity Reading the chart Follow the dry bulb temperature (ver9cal line) up 9ll it connects with the wet bulb temp (diagonal line). The point when they meet is Rela9ve Humidity

Example 1: Dry Bulb: 70°F Wet Bulb: 60°F Rela/ve Humidity: 60% *If wet bulb reached 70, it would be raining.

Psychrometric Chart

Cold Climate Design Data Note: Boston HDD, CDD

Ack – Design Hea9ng Degree Days = 5,641; CDD = 678 MA – HDD = 6,530; CDD = 439

Rating Number: 48832 Certified Energy Rater: Peter Hubbe Rating Date: 1/10/2011 Rating Ordered For: Habitat for Humanity Nantucket 46 Okorwaw Ave Nantucket, MA

Estimated Annual Energy Cost Verified Condition Use

5 Stars Plus Verified Condition Uniform Energy Rating System

Cost

Percent

Heating

21.4

$880

39%

Cooling

0

$0

0%

0.0

$0

0%

Lights/Appliances

26.7

$1227

55%

Photovoltaics

-0.0

Hot Water

Energy Efficient

1 Star

1 Star Plus

2 Stars

2 Stars Plus

3 Stars

3 Stars Plus

4 Stars

4 Stars Plus

5 Stars

5 Stars Plus

500-401

400-301

300-251

250-201

200-151

150-101

100-91

90-86

85-71

70 or Less

HERS Index:

MMBtu

Service Charges

51

General Information

Total

Conditioned Area: Conditioned Volume: Bedrooms:

1824 sq. ft.

HouseType:

Single-family detached

18285 cubic ft.

Foundation:

Conditioned basement

3

Heating:

Duct Leakage to Outside: Ventilation System: Programmable Thermostat:

Fuel-fired hydronic distribution, Propane, 95.1 AFUE. Integrated, Propane, 0.87 EF, 40.0 Gal. NA Exhaust Only: 80 cfm, 150.0 watts.

Heating: No

Cooling: No

Building Shell Features Ceiling Flat:

R-34

Exposed Floor:

Vaulted Ceiling:

R-37

Window Type:

Above Grade Walls:

R-20

Foundation Walls: Slab:

R-20.0 R-0.0 Edge, R-10.0 Under

NA U:0.33, SHGC:0.30

Infiltration: Rate: Method:

Htg: 1.91 Clg: 1.91 ACH50 Blower door test

Lights and Appliance Features Percent Fluorescent Pin-Based: Percent Fluorescent CFL: Refrigerator (kWh/yr): Dishwasher Energy Factor:

TITLE 10.00

Clothes Dryer Fuel:

Propane

0.00

Range/Oven Fuel:

Propane

Company Address

0.00

City, State, Zip

378.00

Ceiling Fan (cfm/Watt):

0.46

The Home Energy Rating Standard Disclosure for this home is available from the rating provider.

REM/Rate - Residential Energy Analysis and Rating Software v12.93 This information does not constitute any warranty of energy cost or savings. Š 1985-2011 Architectural Energy Corporation, Boulder, Colorado.

-0% 6%

$2242

100%

This home meets or exceeds the minimum criteria for all of the following:

Mechanical Systems Features Water Heating:

$-0 $136

Phone # Fax #