Saturday, March 15, 2008

Loft Insulation

not enough loft insulationDo you ever wake up in the night to discover that your partner (or pet cat) has stolen most of the duvet and your uncovered feet feel like they've frozen solid? Imagine going to sleep without any blanket or sheet to cover you. Brrr. If you could get a thin blanket, that would be an improvement over nothing at all. But if you could get a really thick down-filled duvet instead, mmm, you'd be cosy and snug all night.

That's what loft insulation does to your house. Without any insulation at all 15% of your heating costs (about £110 per year)could go straight through the roof. If you have a little bit of loft insulation, say up to about 50mm (2 inches) that would be a lot better than nothing. But if you had a really thick layer of loft insulation, say up to 270mm (about 10 or 11 inches), then every bit of heat stays in your house where you want it, your bills come down, and so does your carbon footprint, by around 1 tonne of CO2 per year.

That's why I climbed up into my loft armed with a ruler, a torch and a camera (you probably don't need the camera) to see how much loft insulation I have. It turns out there's about 80mm up there (just over 3 inches). That's better than nothing, but not really enough.

Since space heating and water heating account for a whopping 84% of our typical household energy consumption, topping up my loft insulation is perhaps the single most significant thing I can do to bring down my energy bills and my carbon footprint. It puts low-energy lightbulbs in the shade. However it's a bit more costly and time consuming than simply buying a different type of bulb whenever one goes "ping". Topping up your loft insulation costs around £200 if you do-it-yourself (maybe £500 if you GALMI - Get A Little Man In). But you'll save the DIY cost in under 2 years of reduced heating bills (less than 5 years for the GALMI version). There may also be grants available. I'll be looking into that over the next few days - if anyone knows anything about loft insulation grants, please drop me an email.

It takes about half a day to insulate your loft, but perhaps more if your loft is full of junk which will have to be removed first. I don't know what the insulating value is of boxes full of old clothes, books and unused sporting goods. I wouldn't rely on it myself.

Do you know how much loft insulation you have? Go and have a look, and then you can click "I've done one thing on the list!" in the poll in the right-hand-sidebar. If you need to add more insulation and you do so, you can click it again.

12 comments:

Killi said...

I have no loft as the upstairs is only half a floor, but Mike, who did my renovation work before disappearing, put as much insulation between the ceiling sheeting & the roof as he could. In my room, I only had 1 skin of blocks, so he put in batterns (3") then stuffed 4" of insulation between the sheeting & the block wall. The middle room is 2 skins & sheeted ceiling (see: http://dikkipenior-killiker.blogspot.com/2007/07/middle-bedroom-upstairs.html)
& the ceiling was done the same way as mine, that leaves Annon's room upstairs which is single-skinned East & West, but thick walls on the South (her room's long) side... Her window doesn't fit properly & it's a cold room, so the door is shut & barricaded & it gets forgotten about. She's in the middle room for now.

I loved going out in the snow & seeing that our house roof was white for most of the day ~ we must be doing something right to keep the heat off the roof :). OK the range wasn't being brilliant & the house was freezing inside, but the snow did stay on the roof!

May I add a link to your blog from mine?

Killi said...

sorry, it posted twice ~ now I won't be able to post again for several weeks!

Joyce said...

We did this last year, and it cut our natural gas usage by about a a quarter. I think it will pay for itself in the next couple of months. And, the house feels much less drafty! It was well worth the effort.

Melanie Rimmer said...

Killi, I deleted the extra post so no worries. I'd be delighted if you wanted to link to Bean Sprouts. I always love it when people link to my blog.

You're right about snow staying on the roof as a good indicator of whether you're wasting heat. It's funny on snowy days when you walk through the streets and you can see which houses have enough loft insulation and which ones need a few more inches.

Angry African said...

This was very helpful! Didn't expect to find it here. Thanks - busy looking into buying a house and this is helping me think through some of the stuff that we need to do.
I'm gonna make a link to my blog. Why? Because this is so different from my blog that my readers might enjoy getting away from me for a bit!

Grant said...

My wife and I added several inches about two years ago, or so. Honestly, I haven't noticed a difference at all. Our house is still ice cold in the winter. Ditto for adding new double-pane windows. There must be a big window open somewhere that I don't know about. *shrug*

Skipweasel said...

Draughts suck away a lot of heat - I'd check that next. Pick a windy day and wander round the house with a lit candle and see where it wanders. If you've got suspended floors downstairs that may be a large sink. Carpets don't really hold the cold air back the way you'd expect. Wall insulation is the other big thing; if you've got solid walls you'll know about it!

Just don't set fire to the curtains or you'll have more heat than you can cope with.

Skipweasel said...

If you've boarded your loft, don't worry - you can still insulate. When we increased ours from an inch or two to 12" I had to do a spot of woodwork. The new beams run crisscross across the old ones. Just slit the new insulation with a breadknife and snuggle the new beams in, then fit the boarding.

Alice said...

I also have no idea how much boxes of books and old clothes would insulate, but I suspect probably quite well, actually. Problem is the gaps in between them.

Is it possible to insulate with waste products of any kind? It'd be worth quite a bit of hassle on sourcing it if it was going to save 200 quid.

How about bags of shredded paper? I get those free from work because they have to pay to dispose of or recycle what I can't take, and I'd have thought it would insulate pretty well - leave it in the bags to keep things not-too-messy.

Is there some kind of catch to this that I haven't thought of?

Debs said...

One of the problems with insulation and then placing boards across is that this creates a thermal bridge which essentially provides a link for the cold to cross your insulated area, thus reducing the effect of the insulation.
Max out on your insulation.
My experiecne of grants is that the work has to be done by approved installers which is more expensive than DIY and of course you still have to clear the attic!!

Anonymous said...

shredded paper may well provide a level of insulation, but it won't be treated against mice etc or be fireproof. I believe the commercial products made from recycled paper etc are treated to help both these issues.

Neil.

sim said...

cool we have the same ruler!