Cavity Wall Insulation

[Mark]

Hi, is cavity wall insulation as effective as some companies make out, e.g save 30% on heating bills? I live in a 3 bedroom semi with gas warm air heating and my last gas bill for the 3 months in winter was £160. The heating is on for about 6 or 7 months. It's cold up here in Scotland.

I use about 20500 kw of gas per year and at present, to heat my hot water with gas is about 20 kw per day, which means I use about 13500 kw for heating per year. So I should be using 4500 kw less per year at a saving of £70.

If I take a lower figure of 20% the savings will be approx £43. Though after the next round of price increases more than likely £50

So even at 20% effectivness I will save £50 per year, not as you are led to believe, a 20% saving on your year gas bill.

I think I have answered my own question as typing this out and doing the figures shows a saving, but not as much as is made out. i.e a saving on the part of the bill that is for heating not the whole bill. I was not going to post this but then I thought someone might find it usefull.

Thanks Mark p.s. I added more insulation to my hot water tank and now my wife is complaining that the towels are not so warm anymore, so it must be doing something.

[Dave Fawthrop]

|Hi, is cavity wall insulation as effective as some companies make out, e.g |save 30% on heating bills? I live in a 3 bedroom semi with gas warm air |heating and my last gas bill for the 3 months in winter was ?160. The |heating is on for about 6 or 7 months. It's cold up here in Scotland.

I had mine done in Yorkshire, not quite as cold, years ago and it has been paying back more every year as the price of fuel goes up. Do it as soon as you can afford it. Makes the house feel much warmer.

[meow2222]

savings depend on construction of house of course. If you can use it, get it.

NT

[David Hansen]

On Wed, 12 Jul 2006 18:56:29 GMT someone who may be "Mark" wrote this:-

Yes, provided it is installed properly. It also makes the house cooler in summer by stopping some of the solar heat getting in.

Also get the loft insulated as much as possible, stop drafts through windows and insulate hot pipes as much as possible.

Various grants are available for some/all of this depending on circumstances.

[Phil Anthropist]

Any saving will be partly off-set by the installation cost, but with escalating energy prices the savings will far outweigh the costs. Good insulation will also add value to the property, and energy ratings will be covered in the new house sellers packs. No one should pay the full price for installing insulation as government grant subsidies are available.

[Guy King]

The message from [e-mail] contains these words:

Wish we could. I'd have to take the tile hanging off the walls to do ours and even then I could only do upstairs.

[Steve]

I know my brother dropped his thermostat by 2C after having it fitted.

I've just had it done to a 4 bed detached through powergen and it cost £150, even using your predicted returns, the payback rate is still quite quick.

Steve

[Christian McArdle]

Just do it. Apart from the savings in fuel, you also get other benefits, such as reducing your carbon footprint and making the house much more comfortable, as the walls get warmer giving radiative heat, which the human body finds particularly acceptable.

Christian.

[Mary Fisher]

Hear hear!

We had it done years ago, there were no grants, it cost more than twice as much as it does now not taking account of inflation. We noticed a difference in comfort from Day 1. I haven't looked at bills but we had to adjust our thermostat, our outgoings must have decreased.

That's the individual point of view. Christian's point of the general effect on the environment is more important.

Do it.

Mary

>

[Doctor Drivel]

Which is all negated by the millions of insulationless conservatories heated. People build conservatories to gain extra living space because our houses are too small. Change the Draconian Stalinist planning system, up the insulation levels in the building regs and energy usage will eventually drop.

[Broadback]

I am in the process of getting loft and cavity wall insulation. To date I have had 2 bods round to give estimates, they could not have been different. The first simply measured and gave the estimate, I asked a few questions to which he barely replied. The second chap brought up every query I had and his solution without my saying a word. Also he was very precise about making sure everything is well sealed (waste pipes etc.)before cavity wall insulation, also pointed out that the vents I have in the wall for the toilet and cloakroom must be through vents, the installers will check and if not install the required types at installation time, at an extra cost of course. Strangely his estimate was the lower one. So pick your installer with a little care.

[manatbandq]

But make sure there's adequate ventilation to prevent condensation (and thus damp) in the now colder loft.

MBQ

[meow2222]

Exterior tiles dont prevent cwi, just feed the hose in thru the window and inject on the interior side instead of the exterior. Is that what you mean?

NT

[Guy King]

The message from [e-mail] contains these words:

It's already got /some/ rather tatty insulation behind the builder paper. Some houses in the row have had the tile hanging removed and a render applied over thicker insulation. Trouble is it doesn't look as nice.

[Weatherlawyer]

I wonder what the costs are?

You use labour at just over the national minimum rate. A lorry, a pump and some piping. An SDS type drill and some packing. Replacing vents is a bonus and the material is light as air so doesn't cost an arm and a leg to transport.

The alternative is to carry you own bags of vermiculite or whatever to the loft and try and pour it down the cavity. An unpleasant job you could do in the winter as the mood took you. Total cost = the material used.

Thinking about it now. You could put a piece of ply on the inner leaf of the cavity and rest a 4 or 5 inch downspout on that and pour the material from the middle of the roof quite easily.

The particles would spread out in a cone filling half way up the cavity by the time the pipes needed moving.

How feasible is that?

[google]

How do you get it to fill under the windows?

[Weatherlawyer]

Good point, is hat the only difficulty?

Either remove the window boards and fill them and use the occasion to check on the method while at it.

Alternatively drill a hole through the boards and fill through them. Less messy but not appealing for the nosey, find out how it ticks, type of DIYer.

How do conventional firms get it to fill under the windows? How do customers of conventional firms get check it filled under the windows and everywhere else?

If you run a tape from the DPC to the wall plate and also measure the length and width of the house, you can work out the likely volume of filler required. If you fill to the probable height of the cills of the lower windows and let it settle it might level out with the draught that seems to accompany cavity walls.

Some time later, further filling should get it to the bottom of the upper windows. After another period the house could be filled. And then some more added intermittently to top up for settlement.

If I couldn't afford it I'd see if I can get a grant for DIY. If not; see about setting up a company called the I'm going to do it myself co. And reapply for the grant.

[Dave Fawthrop]

|If I couldn't afford it I'd see if I can get a grant for DIY. If not; |see about setting up a company called the I'm going to do it myself co. |And reapply for the grant.

Setting up and closing down a company would cost more paying for the full cost of cavity wall insulation.

[Weatherlawyer]

That would depend on the clauses required for the council to accept the quote. A letterhead produced by junior from the family PC would be enough surely?

[John Stumbles]

This is a DIY newsgroup, so here's how to work it out for yourself :-)

Use a whole-house calculator intended for sizing replacement boilers such as:

that the latter, at least, has errors dealing with floors and/or roofs of flats)

and see what difference selecting filled or unfilled cavity walls makes. Then do appropriate arithmetic to see how that translates into what difference it would make to your fuel bills.