Heating?
The solution is under your lawn.
Country Life - April 20th 2006
The Queen is doing it. Elton John is doing it. And it will save you thousands of pounds. So why are we not all joining in? I am not talking about throwing lavish birthday parties, or ordering bouquets of f lowers, but something that applies to us all—how we heat our houses.
With rocketing oil and gas prices, it seems that Buckingham Palace and a sumptuous dwelling in Ascot have found a way to use the earth’s natural heat without burning increasingly pricey fossil fuel. Should not every Old Rectory, Georgian manor and cottage across the land be following suit and installing a geothermal heat-exchange pump?
Heat pumps are not new. They are popular in Sweden. But despite being credited with producing free and inexhaustible energy, there is still only a handful of suppliers in this country, and you would be lucky to bump into anyone who had installed a system. The reason is partly lack of awareness and also the belief that they only work in new houses, although developers remain cool about them because of the extra start-up cost. However, they may suit some older country houses. For a start, it helps to have a large lawn, or even a small lake.
A geothermal pump works along the same principle as a refrigerator, but in reverse. It consists of a series of long loops of plastic pipe called ‘slinkies’ buried 6½ft down where the soil temperature in the UK is a reasonably constant 10°C. The more heat the house needs, the more plastic needs to be buried. A mixture of water and antifreeze is pumped through the pipes and the heat pumps. When it emerges from the ground, it is compressed to a higher temperature by the heat pump—up to a maximum of 50°C, to heat the radiators. Although the heat is effectively free, the heat pump itself uses electricity. ‘Depending on the house, it will very efficiently take the temperature of the water up to 35°C for underf loor heating,’ says Justin Broadbent, director of ISO, a firm that specialises in supplying heat pumps to country houses. "By putting in one Kw of electricity, you will get a return of four Kw of heat. The trouble is that most radiators need about 50°C water temperature and this only gives a three times return on power, and so the system runs less efficiently than with underf loor—but it still beats the running cost of oil by miles," he says.
"I am a firm believer that this system is good for older houses. Underf loor heating is ideal, as you would not need more than 35°C. But I realise that you do not want to install this in a lot of old houses, so insulation is also very important. By this, I mean draught exclusion in the loft, secondary glazing that can be removed and insulation." Mr Broadbent is speaking from experience. He has a 16th-century house where he has been unable to install underf loor heating. He has put in larger radiators that can radiate more heat with lower temperatures.
A small manor house near Yeovil with old castiron radiators has managed to reduce heating costs by up to 75% after Kensa Heat Pumps of Falmouth installed a system in 1999. At Enstone Manor near Oxford, the new owner was determined to use a heat-pump system, and a new ‘wet’ underf loor heating system was fitted throughout the house and a very large pond dug to supply the heat source. After leaving the pond and travelling through heat pumps, the water is then passed to a new fountain and water feature before draining back to the pond by gravity. Michael Campbell, who owns an eightbedroom Georgian farmhouse near Alton in Hampshire has heat exchangers connected to a ring of two plastic pipes buried under beautiful lawns. The heat pumps, originally imported from Sweden, had not been used for some time because of technical problems and the importer had ceased trading. But then engineers from Kensa renovated the heat pumps and re-commissioned the system. The heat pumps are connected to radiators and a gas boiler supplements the heat pumps in cold weather. ‘I think it is an eminently sensible way of using free energy,’ says Mr Campbell, who runs a family investment company. ‘It has cost me nothing to maintain the underground pipes, and the whole thing is pretty hassle-free, particularly compared with the gas boiler that I have just had to spend £1,800 on repairing.’
So where is the catch? Installation costs do not come cheap. For a 4,000sq-ft Old Rectory, it might cost you £20,000 to install, depending on how much extra insulation is required. Houses with small gardens can still put in a heat-exchange pump, but they will need to drill down rather than laying the pipes horizontally and this is more expensive. But if you are making 75% savings on your fuel bill (which for the same house could be £4,000 to £5,000, using oil), then you will make your money back within a few years. ‘I used to advise people to allow seven years to recoup their money,’ says Mr Broadbent. ‘But with the recent hike in oil prices, I now say five years.’ Heat pumps certainly suit large houses open to the public, that do not necessarily need rooms at the usual comfort zone of 21°C. Many rooms in a National Trust house could be kept between 14° and 16°C to ensure contents did not become damp. For the rest of us, it is certainly worth considering if you are planning to stay in your house for some time. And even if you are not, it could soon be the case that a house with a heat pump will be much easier to sell than one without.