Heat of the moment

Electric underfl oor heating has grown in popularity over recent years and is now considered one of the most effi cient ways to heat a building. This should be good news for contractors

By Rob Shepherd

Although underfloor heating is by no means a modern concept – its use can be traced back to Roman times – it is only in the past 20 years or so that using electric-based systems in this way has become more common. Leading the way has been Scandinavia, where underfloor heating under tiled and wooden floors in lobbies, kitchens, bathrooms and conservatories is considered the norm.

These systems work by passing a current through a cable and the electrical resistance of the cable causes a heating eff ect. The inner heating element is earth-sheathed and electrically insulated from the working surface, so there is no danger of electric shock. Electric underfloor heating cables do not have to get very hot in order to warm the floor and most systems incorporate a floor thermostat, as well as a room thermostat.

Crewe-based NICEIC Domestic Installer DC Technical Solutions has been installing electric underfloor heating for the past 12 years. “We have seen a change in terms of our client base in that it is now accessible to most people in terms of cost and simplicity of installation,” says company director Carl Morley. “A greater number of products have come on to the market off ering lower costs and more flexibility.”

David Goose, managing director of Ambient Electrical, agrees. “Electric underfloor heating is no longer seen as a luxury item,” he says. “The costs have dropped considerably over the past decade, with decent quality systems being around 25 per cent lower in price than they were in 2005.”

Type cast

Diff erent formats are designed to suit specific floor surface types. Mat-based and loose wire systems are perfect for installation under ceramic, tile and natural stone, while foil systems are suitable for use with laminate, carpet, vinyl, engineered wood and other floating floors.

“The most common forms of electric underfloor heating are the floor heating mat and the floor heating cable,” explains Jonathan Jones, global product category manager at Pentair Thermal Management. “The heating mat is designed with the installer in mind and is the quickest and simplest solution to install. With the heater pre-installed onto an adhesive lined mat, not only can it be fixed to the subfloor really quickly, but the power output per square meter is also

pre-defined, meaning the installer does not need to calculate cable spacing in order to achieve a specific heat output.”

The overall heat requirement of a room will depend on its size and its heat loss characteristics. Dividing the total heat loss by the floor area will give the heat requirement in watts per square meter (W/m²) and it is then easy to specify the amount and type of matting, foil or wire required.

Benefit check

Given that most people are used to having wall-mounted, water-based radiators, the argument for switching can be diff icult. But there are some real practical benefits to electric underfloor heating, most significantly that it delivers an even radiant heat across the whole floor area, with no cold spots.

“Tests have proven that the average room temperature can be reduced by 1-2°C compared with a traditional radiator-heated room before the occupant feels any diff erence,” says Jones. “We tend to feel the cold in our extremities first so if the heat source is at floor level our feet are kept warm and our whole body feels warm too.”

Although it can be used in commercial premises, it is more commonly installed in domestic dwellings. “I’ve carried out installations in range of newbuild, retrofit and refurbishment projects,” says Tony Cox, managing director at Gloucester-based NICEIC Approved Contractor AJC Electrical. “But most of the customers I install it for are those having new conservatories built and bathrooms revamped.”

Joan Pask, group marketing manager at Warmup, believes that electric underfloor heating is especially suited to new, low-energy houses. “New buildings – especially Code for Sustainable Homes (CSH) Level 4 or higher – are considerably more airtight and insulated than pre-2006 homes, with the energy requirement for CSH 4 dropping from 55kWh/m²/year to 24.83kWh,” she points out.

When it comes to renovations, electric systems have the benefit of not relying on the rest of the heating system, says Steven Rooney, sales director at Gaia Climate Solutions. “If an existing system is at capacity, electric underfloor heating can be installed without upgrading the boiler,” he says. “And homeowners don’t have to turn on the rest of the system if they just want a warm floor.”

Rest and relaxation

The London Syon Park Hotel sits at the edge of the 200-acre Syon House estate in Brentford, and its 137 rooms and seven suites provide a touch of luxury for its guests. Part of this experience comes from electric underfl oor heating, using the Raychem intelligent underfl oor heating system from Pentair Thermal Management. The installation uses a number of diff erent elements. T2Red with T2Refl ecta was installed in the bedrooms, combining self-regulating heating cable with a pre-grooved aluminium-covered insulation profi le to reduce heat loss and provide an even heat distribution. In the bathrooms, > Underfl oor heating adds to the T2Quicknet 160, a thin self-adhesive heating mat, luxury in the hotel bathrooms provides fast heat-up time and, at only 3mm thick, is ideal for installation under tiled fl oors.

“The developers were looking for a smart heating solution that would provide high levels of comfort,” says Jonathan Jones, global product category manager at Pentair Thermal Management. “The hotel now has a reliable, energy-effi cient solution that allows guests to immerse themselves in the luxury that this country retreat off ers.”

Money matters

One of the most frequent criticisms levelled against electrical underfloor heating – as well as electric heating in general – is that it is expensive to run compared with gas central heating.

It’s a claim that Mark Russell, design and marketing manager at the Underfloor Heating Store, refutes. “According to independent energy watchdog Energywatch, since 2003 gas prices have risen by as much as 92 per cent, while electricity prices have only increased by 54 per cent,” he says. “When installation, servicing and maintenance are taken into account, overall cost-eff ectiveness comes out in favour of electric underfloor heating.”

This is a view shared by Sarah Macfarlane, Myson’s product manager for electric underfloor heating. “It’s all about using the right controls, just as you would with any heating system,” she says. “Electric underfloor heating provides perfect zone control and can be used in unexpected chilly spells in warmer seasons to provide warmth without using the central heating boiler.”

Meeting the need

The installation of electric underfloor heating should be a welcome addition to most contractors’ service portfolios and represents an opportunity to diversify into a new and exciting sector.

Given the simplicity of installing the systems, little or no additional training is required. “Installing underfloor heating is quick and easy and should provide no real challenge for a professional electrician,” says Macfarlane. “What it will provide is a useful new revenue stream that takes the electrician more firmly into the arena of home improvement, not just home maintenance.”

Being part of the broader energy eff iciency agenda should help contractors position themselves for the future, suggests Pask. “Flexibility is the key to future business expansion and profitability and requires meeting customers’ needs for highly targeted, personal solutions,” she says. “To achieve this goal today’s heating contractor must take advantage of training to keep ahead of market developments such as the smart home.”

Economical to run and requiring little maintenance, it’s no surprise that electric underfloor heating is growing in popularity. The use of gas and oil boilers is not sustainable and electricity is the key to future home heating. With significant opportunities for electrical contractors and the economy on the up, now could be the perfect time to explore what’s on off er.