Environmentally sound eco-homes aren’t just for architects and self-builders. They’ve just pioneered the techniques, but with every passing year, the know-how to build zero carbon buildings trickles further down through the industry. As more homes are built to high efficiency standards, the expertise spreads and the costs come down, making it easier for others to build them too.
One example is the St Mary’s development in Oldham, which was completed last year. The council bulldozed an area of sub-standard flats, and replaced them with state of the art Passivhaus dwellings. Like the last building of the week I profiled, this is social housing, managed by the housing association Contour Homes.
If you haven’t come across the term Passivhaus before, it refers to a design approach that creates houses that are so efficient that they don’t need heating. Cooking and the body heat of occupants is enough for all but the coldest of days. This is achieved by making the house airtight and packing the outer walls with insulation. The house is then ventilated through a heat exchanger that extracts warmth from the stale air being vented out, and uses it to warm the fresh air coming in.
The cost of heating one of Oldham’s passivhauses, for an entire year, is around £20 or so. By contrast, the average household spends around £13 on space heating every week.
Building these homes to this standard added £20,000 to the build cost.