The 4-bedroom house has a sauna and Jacuzzi, but its entire requirements can be met by the one boiler. Most of the time, sufficient heat will be provided by a combination of solar energy and the heat given off by people and appliances. Designer Mike Hillard expects the heating bill to be £30 a year, with hot water costing a further £10.
The Ferroli boiler was chosen for its ability to be de-rated to meet the low demand.
The underfloor heating system is fed from a 7000 litre storage tank heated by solar energy with occasional support from the Tempra boiler. When there is not sufficient solar energy, the boiler can boost the temperature of the store while operating at maximum efficiency without wasteful cycling.
The house uses readily available products and building materials, including insulation, pumps, actuators, sensors and controls and is estimated to cost just 5% more than a standard house.
