U.K. House Generates More Energy Than It Uses

Insulation and Airtightness Are Key in Reducing Energy Use.

CLAPHAM, UNITED KINGDOM — Owner-builder Will Anderson claims that the house he completed in 2006 produces more energy than it uses. Equipped with a 4.3-kW photovoltaic(PV) Generation of electricity directly from sunlight. A photovoltaic cell has no moving parts; electrons are energized by sunlight and result in current flow. array, Anderson’s all-electric home is heated by a ground-source heat pumpHome heating and cooling system that relies on the mass of the earth as the heat source and heat sink. Temperatures underground are relatively constant. Using a ground-source heat pump, heat from fluid circulated through an underground loop is transferred to and/or from the home through a heat exchanger. The energy performance of ground-source heat pumps is usually better than that of air-source heat pumps; ground-source heat pumps also perform better over a wider range of above-ground temperatures.. The heat pump also supplies a portion of the home's hot water, with the remainder supplied by a solar thermal system.

The walls of Anderson's house are framed with 12-inch I-joists used as studs. The cavity walls are filled with cellulose insulationThermal insulation made from recycled newspaper or other wastepaper; often treated with borates for fire and insect protection.. All windows are triple-glazed. The tight house is equipped with a heat-recovery ventilation(HRV). Balanced ventilation system in which most of the heat from outgoing exhaust air is transferred to incoming fresh air via an air-to-air heat exchanger; a similar device, an energy-recovery ventilator, also transfers water vapor. HRVs recover 50% to 80% of the heat in exhausted air. In hot climates, the function is reversed so that the cooler inside air reduces the temperature of the incoming hot air. system.

Last year, Anderson’s PVPhotovoltaics. Generation of electricity directly from sunlight. A photovoltaic (PV) cell has no moving parts; electrons are energized by sunlight and result in current flow. array produced 4,470 kWh, while his “carbon-negative” house used only 4,352 kWh — considerably less than the typical British household, which uses 26,000 kWh per year on average. Anderson told a reporter from The Guardian, “There is a lot of fretting in the building industry about how to achieve a zero spec, but it’s all to do with demand. People get obsessed by the supply side. And the supply side, with all the technology is more visual, so fair enough. But the key thing is to get the demand down. Insulation and airtightness are key.”

For more information, visit http://www.treehouseclapham.org.uk.