Innovation: Lights are on but nobody's home: Model houses inhabited only by mechanical 'poltergeists' will test the efficiency of heating systems

ESTATE agents would describe them as modern, comfortable and desirable, but two furnished houses recently built in Cheshire will be home to light bulbs rather than people.

The houses, identical in every detail, will be used to compare the efficiency of domestic heating systems. They have been built by the energy research and development company EA Technology, at its site in Capenhurst, near Chester.

Proving a domestic heating system is more energy-efficient than another usually involves expensive field work using test systems in real houses. 'The problem is there are too many variables,' says David Strong, director of EA Technology's energy and buildings division.

Even if the houses are similar, the occupants live differently: - they like different temperatures, and close windows and doors at different times. 'If you've got a big enough sample you can begin to draw something out of it,' Dr Strong says.

The houses will have resident poltergeists - or systems for mechanically opening doors and windows, and drawing curtains. Heaters will simulate heat output from cooking and television sets, and people will be represented by 60-watt bulbs, which Dr Strong says throw out as much heat as the average body. Both four-bedroom houses will be subjected to identical regimes, allowing the efficiency of one heating system to be compared with another. Data will provide the independent proof manufacturers need to qualify their products to be subsidised by the Energy Savings Trust.

The trust, set up by the Government 18 months ago to help the UK meet its commitments to reduce carbon dioxide emissions, gives pounds 200 grants to householders who instal heating systems that are recognised as energy-efficient.

Dr Strong says he is confident the simulation of 'family life' in the houses is realistic. 'We have 30 years of experience doing this type of measurement with real people.' The houses were designed to the latest building regulations, published last month. 'In thermal terms they are typical of the houses that will be built in the next 5 to 10 years.'

Because temperatures inside the houses can be finely controlled it will be possible to simulate a full annual cycle of spring, summer, autumn and winter in a few weeks, regardless of the external temperature. Building work finished six weeks ago, and the houses are now being calibrated to ensure they are thermally identical.

The first equipment to be tested is a heating system developed by EA Technology for a consortium of electricity companies and UK manufacturers including Creda, Dimplex and Thorn. Using the houses will cut the cost of these trials by 90 per cent.

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