Danielle Bowling reports on how designers can bring the heat out up from the ground.
With winter just around the corner, Australians are bracing themselves for the chilly mornings that make getting out of bed in the morning that little bit harder. Australians are also readying for higher electricity bills, which in many house holds, will be considerably more costly than they are in summer. Not to men tion the little pang of guilt some peo ple feel when they think about what their heating habits are doing to their carbon footprints.
Underfloor heating is an alternative to air-conditioning, fire places and heaters. It also has the added benefit of warming the entire house or a whole room, rather than just one corner of it.
John Thwaites from Speedheat, which provides a range of heating options, including tile floor heaters, carpet floor heaters and under timber heaters, says “It’s more efficient than using, say, the same amount of power at a radiator because it’s taking that same power and instead of concentrating it in one corner of the room, it’s spreading it evenly through the floor. You’re evenly raising the tem perature of the room as opposed to overheating one part of the room and trying to get the movement of heat through the room, which takes time and actu ally uses more power.”
Speedheat installs its 1 mm thick heating technol ogy directly under the floor covering, rather than in the slab or screed. This means it can heat a room or a house quicker than other floor heating technologies, which require more time and energy for the heat to travel through, say, the cement under the floor finish.
“We use less power to do the same job and it’s really just because we’re not hav ing to heat through layers of cement. We’re already on top, and those layers are acting more like insulation rather than impeding the heat rising,” Thwaites says. “So the difference with our product is that it’s the thinnest, and being so thin you can stick it down onto the slab and it’s not going to annoy the tiler.”
Having less of a lag-time between when the system is turned on and when the house is warm means less energy is consumed — something which will have a positive impact on electricity bills and the aforementioned guilty conscience.
Thwaites explains that while the sys tem may be more costly than air-condi tioning in terms of the initial outlay, the long-term savings make it a worth while investment.
“Once they [the property owners] get a quote, we show them the running costs, which is where it’s going to use around 20 per cent less power than an in-screed cable...We base our quotes on about 80 to 100 watts per sqm. That’s what our system will use to heat, and if you’re buying an air-conditioner, it’s rec ommended that you use 125 watts per sqm, so we’re generally using less power than air-conditioning as well,” he says.
Underfloor heating can be pro grammed to turn on and off at certain times of the day and at specific tem peratures. Each room in a property can also have a separate thermostat, which displays how much energy is being consumed.
P.A.P. Heating Solutions’ managing director, Peter Heany, believes under- floor heating is becoming more popular, particularly in residential developments. He says it is the system’s ease of use that makes it such an appealing option.
“It’s the sort of heating system you turn on at the start of winter at a certain temperature and you let it run by itself and moderate the temperature depending on the climate at the time. If it’s cold, it’ll heat up more. If it’s not, then it won’t heat up as much,” he says.
Like Speedheat, P.A.P. Heating Solutions has a range of heating products, including under-tile heating cables, heating cables for frost protec tion (commonly used in commercial freezer rooms), a self regulating anti- front system and an in-slab off-peak heating system.
The in-slab system, Heaney explains, is installed in a concrete slab prior to the concrete pour. “There is a thermostat installed in each room and that is connected to an electricity tariff called off-peak electricity, which is a cheaper tariff that heats up in the night and during the middle of the day. The way the concrete slab works is that it absorbs the heat very well...and then when it gets to a cer tain temperature the thermostat turns it off and the heat is stored in the concrete slab. So as the temperature in the room cools down, the heat is drawn out of the concrete slab — hot to cold,” he says.
“It’s an essential heating system, so in other words it’s the sort of heating system you’d use in Canberra and the southern parts of Australia, Tasmania and parts of Victoria.”
During the 2008/09 end-of-year university holidays, Speedheat installed its under carpet heating technology in almost 40 rooms over two floors at the Sydney University Women's College. The heritage-listed 1894 building was refurbished, with the major bathrooms renovated, new switch boards put in place on each floor and a separate circuit running to each room. The carpet was also replaced, making under carpet heat ing both a convenient and a practical option.
“We had column heaters here in the individual rooms and we thought [under carpet heating] would be a more energy efficient way of heating the rooms because the column heaters were only small ones and it gave warmth to the room if it was on for a long time and you were sitting close to it. Whereas with this style, it spreads the heat out more evenly,” says Daniel Wetherall, facilities man ager at the Women’s College.
Wetherall can’t say for sure that the heating technology is more economi cal than other options, but he does believe that it’s the most practical option, especially because each room has its own thermostat control.
“They can turn it up or down to their own liking. I think you can have it so you can actually have one con trol that will do all of the rooms and you can turn all of them off. That was one option we had ... so they couldn’t use it all the time, but being a resi dential college where the girls go to uni and some are studying during the day and some are out and some are in, it wasn’t practical, so that’s why we went down the track of having all the individual controls,” he says.
Installing air-conditioning would have been difficult, not only because of how old the three-storey building is and its heritage listing, but also because it would require regular maintenance.
Wetherall says: “We’ve got air-con ditioning in other parts of the build ing — in the dining room and in the function areas and every quarter we’ve got guys coming out and doing some maintenance on them, or some sort of repairs. But this system seems to be working fine. It generates quite sufficient heat for the rooms.”
