A house that lives off power

Builders may grouse about the impossibility of making Britain’s homes green but a Danish window group believes it has the answer.
In July the Simonsen family moved into a pioneering eco-home near the city of Aarhus. The so-called Home for Life, built by Velux, a 60-year-old firm still owned by the founding Rasmussen family, doesn’t need to take gas or electricity from the grid. Thanks to its big windows, solar heating and natural ventilation, the house will generate more power (in summer) than it consumes.
So how does it work? Solar heaters provide the hot water and photo-voltaic cells on the roof power the appliances. The house feeds excess power into the grid, which pays for the electricity used in winter when the sun shines less.
Per Arnold Andersen, one of Velux’s chief architects, said comfort hasn’t been sacrificed. “The worst thing you can do is just insulate, insulate, insulate. In Denmark there are some pretty scary examples of housing from the 1970s with tiny windows, low natural light and a poor indoor climate,” he said.
Insulating without thought for summertime temperatures can lead to homeowners buying air conditioners, and poor natural lighting means they are more likely to have lights on during the day, he added.
To prevent the house overheating, smart windows regulate the airflow, venting heat automatically through roof skylights.
The big question, of course, is expense, and not every new home can be perfectly angled to capture maximum sunlight or wind.
Andersen declined to say how much the Home for Life had cost but said that rolling out the design on a large scale would make it affordable. “Our approach is simple and is based on known technology. It is more expensive initially but the pay-back time will be fairly good.
“When you look at the lifetime of the building, it will be cheaper.”