It's curtains

Chris Hamlin writes:

Hi Mark
After reading your blogs and general ranting on the stupidity of HIPS, I still have never seen anything mentioned on the efficiency on curtains as an insulating material. On our old cottage, with part double-glazing, part older character windows, we have home-made blinds and combined with curtains which are lined and inter-lined. I would suggest the rating must be equal to or better than a modern double glazed window. The house can warm up more during the day through the single sheet of glass, and then retain that heat when the blinds and curtains are closed after sunset.

Also the house has 2ft wide solid wall construction. Might this be more or less efficient than cavity wall + insulation? Does anyone know?

I'd like to see government helicopters mapping the city at night with their heat photographing cameras and targeting the few really bad leaking buildings (and cannabis dryers!) directly and leaving the rest of us alone, instead of stimulating another raft of inspectors.


Mark reckons:

Some interesting points, Chris.

I still have never seen anything mentioned on the efficiency on curtains as an insulating material

I suspect that's because no one has ever measured them. I think a lot would depend on the degree of draft-proofing but in theory a single sheet of glass should admit more heat during the day and a thick drape would act something like a second sheet of glass at night. But equal to, or better than? Who could say?

Also the house has 2ft wide solid wall construction. Might this be more or less efficient than cavity wall + insulation?

Measurements have been taken on solid wall materials. Generally solid stone performs very poorly, from a conduction point of view. You need something like a 3ft to 4ft thickness to achieve the equivalence of a modern cavity wall. And if it gets wet, it's almost useless.

I'd like to see government helicopters mapping the city at night with their heat photographing cameras and targeting the few really bad leaking buildings (and cannabis dryers!) directly and leaving the rest of us alone, instead of stimulating another raft of inspectors.

Well that would be really popular, wouldn't it! Can you imagine getting a heating ticket from a flying thermographic camera! Maybe one day soon, they'll be able to do it from satellites.