Greenhouse effects: Home insulation

More heat is lost through the walls than any part of the home, solid-wall insulation can cut heat loss dramatically

Tony Juniper

Speaking to a Norwegian friend last week, I was reminded how far we have to go in the UK in improving the efficiency of our homes. She remarked that she had never been as cold as during a spell in England this winter, even though temperatures here are higher than in Norway.
Heating is vital for our comfort and health, but it is also the biggest contributor to a household’s carbon footprint. More heat is lost through the walls (up to 50%) than through any other part of the home.
Cavity-wall insulation can cut heat loss dramatically, but for the many properties with solid walls — about 36% of households — a different solution is required.
Homes built in solid brick (like our Edwardian semi) or stone are not easily insulated — and as well as the millions of houses with solid walls, nearly half of the 326,000 high-rise flats in England are similarly built.
If you have solid walls, fitting insulation might be one of the most effective environmental measures you can take.
External wall insulation involves adding a weatherproof insulating layer to the outside; the typical cost for a three-bedroom semi is between £3,500 and £5,500. If done at the same time as renovation work, however, the cost might drop to about £2,000. For more information, visit nationalinsulationassociation.org.uk and inca-ltd.org.uk. Remember that there might be planning issues linked to external cladding, especially if you live in conservation areas or listed buildings.
Internal insulation takes several forms, including ready-made laminates or wooden battens in-filled with insulation. Typically up to 90mm thick, this material will reduce the size of the room, and will require the removal and refitting of cornicing, picture rails and skirting. Expect to pay about £3,600. There are thinner alternatives, such as Warm-a-Wall, a flexible lining 10mm thick that is applied like wallpaper. It can be skimmed or painted — see walltransform.co.uk. Another is Sempatap thermal (www.enviro-materials.co.uk).
Tony Juniper is an environmental campaigner and former director of Friends of the Earth; tonyjuniper.com
greenhouse@sunday-times.co.uk