Adventures in home insulation

photo (8)Yes, another riveting subject – hard on the heels of my post on public transport! I know how to draw a crowd on this blog…

My latest obsession came about via a random click on an ad for ‘free’ solar panels. We turned out not to be eligible, but then I discovered the government feed-in tariff for home solar panels. I was hooked. Hippy that I am, I love the idea of generating renewable energy – but in this case I’m mostly motivated by greed. The deal is that the government will pay you for every kilowatt hour of electricity your panels generate, whether you use it or export it to the grid, for twenty years. You can also expect to halve your electricity bill. The quote from one solar company estimated that the panels would pay for themselves (£5400) within five years, and then keep making money – £1000 in the first year and steadily increasing (this includes savings from the rising cost of energy). As we have a bit of south-facing roof and are not planning to go anywhere for the next 10 years at least, it seems like a no-brainer.

The only catch is that your property needs to have an Energy Performance Certificate (EPC) of ‘D’ or above to qualify for the tariff. We don’t have a rating yet, but when I did a quick test on the Energy Saving Trust website it rudely gave our house an ‘F’. The Edwardians who built it didn’t seem to have given a hoot about global warming or EPCs and we haven’t upgraded our single glazing, solid walls or pathetic layer of loft insulation (partly composed of 1960s newspapers and women’s tights – insulating properties unknown).

So last week saw Mr Suburbanite and I crawling around the loft wearing head torches and face masks, removing debris and laying down a base layer of mineral wool. It is thoroughly painful work – the roof space is four foot max on one side and drops to nothing on the other, plus that pitch black attic dust (what the heck is it made of?) gets under your mask and into everything, with a marked preference for nasal passages. We also found (empty) wasps nests and fossilised cat poo from an unfortunate era in our past when the cat thought she’d found a giant litter tray in the roof. However, I did feel a certain smug satisfaction – greater even than the warm glow of knowing that my sock drawer was in perfect order, which I experienced once in 1998 – of thinking I’m doing something with my own hands which is going to make a difference. To the heating bill, that is, though I also hope it will impress the EPC inspector.

Nowadays the 100mm depth of mineral wool which fits nicely between the joists is not enough – lofts need the equivalent of 270mm of wool to be considered effectively insulated (or a U value of 0.16 wm/k. Don’t ask me what that means). It took a while to find the best solution for having both flooring, to store all our clobber on, and the right insulation thickness (without squashing the wool under the flooring – that stops it working). After investigating lots of complex ideas like constructing a special floor that stands on steel supports above the level of the wool, we found that simple is best – we’re going for two layers of cheap loft floorboards sandwiching a layer of rigid insulation board in between to take it to the required thickness. Ta-dah! The insulation arrives on Friday so in theory it will all be in place soon after.

Cold winter? Bring it on! No longer will ours be the only house in the street without frost on the roof while all our central heating seeps out through the tiles.

I could bore you with the other steps we’re taking – radiator reflector panels and draught proofing and LED light bulbs – but, well, I just did.

Come back next week for my exterior wall cladding and double glazing fantasies. There’s about to be government cash back incentives for both apparently. Look closely into my eyes and you’ll see the ££££ printed on the retinas…


3 thoughts on “Adventures in home insulation

  1. Black attic dust is solidified London air. Everyone knows that.

    I also seem to remember that the cat thought my suitcase was a slightly less giant litter tray … thankfully diet cat food largely goes through the cat unaltered

  2. Pingback: We’ve got the power | Subversive Suburbanite

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