Does replacing single with double glazing make financial sense?

[gm99]

I'm sceptical about the value for money arguments regarding replacing single with double glazing if the windows don't have to be replaced (e.g. because they are rotten beyond repair) and would be interested to hear any views informed by experience or professional expertise. [This is specifically about value for money - not sound insulation, the environment etc.]

My thinking is:

If 20% of heat loss for an average house is through the windows, and double glazing reduces that by a half, the maximum saving per year is around 10% of heating costs (c. ?80-100 on a 3-bed Victorian house?). Given the cost of replacing all windows with double glazing (?5-10k+?), and the more limited lifespan of double glazing (20-30yrs due to seals failing) it looks like it makes more financial sense to simply cut out draughts where possible and leave the heating turned up. Am I missing something?

[david_carnell]

No - you're not.

Loft insulation and cavity wall insulation both make more financial sense in terms of value for money.

The only other factor to bear in mind would be that good double glazing adds value to your home and makes it more likely to sell promptly.

[Jeremy]

Yes, but I don't think energy savings is the only argument - e.g. noise, draughts, etc.

Many houses in the area have solid walls without a cavity, so cavity insulation may not be an option.

[MrBen]

Aye. Agreed.

I'm not sure good double glazing adds value though. Chunky PVC frames can make a period property that wasn't designed for them look awful and posh middle class folk who want to restore sash style on a traditional terrace will be pricing that in.

Most single glazed sash windows can now have timber repaired, beading and cords replaced and be draught proofed with a recessed draught proof strip for around ?250-?300 each. Much cheaper than the ?500-?800 for a double glazed sash replacement. Once redecorated these look great.

A specialist restorer (for same price above) can now use Epoxy resin like Timbabuild or similar to virtually rebuild rotting timber frames which can then be drilled , painted etc just like new wood. I've just had someone do this and it's great.

So to the OP (assuming an average non-eco victorian flat/house), I would restore your current windows and draught proof, get decent double lined curtains or blinds and get your central heating up to spec (flush your central heating system out ?250-?300, boiler serviced) to get decent heat retention.

Cavity wall insulation is good but a lot of old buildings are "single skin" just two solid bricks separating your plastered wall from outside. I once dry lined two external facing walls of a room with insulating plasterboard and that worked well.

[PeckhamRose]

I live in a block of flats. Nearly 3 years ago we had double glazing put in the whole block. We have had to pay ?8,500 but of course that will add the value of block should we ever leave. We have a two bedroomed flat but it is on a sort of peninsular of the block so we had windows and private balcony doors on 3 sides.

Since that day we have only put our fire on twice. So even with all that snow and nastiness, only twice did we need the fire on, when - beforehand - we had it on every day in winter!

Despite raises in fuel prices, our fuel bills are actually still less.

As long as you have a healthy efficient boiler too, all should be good.

(We had 3 years interest free to pay off the ?8,500 and had several years' notice by the way!)

[red devil]

I agree with what MrBen said about uPVC double glazing in a period property...you are more likely to devalue the property, negating any energy savings.

[womanofdulwich]

but a good thing is you will cut down on your external decorating costs. ;-)

[peterstorm1985]

womanofdulwich Wrote:

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> but a good thing is you will cut down on your

> external decorating costs. ;-)

Mmmm, is that because there is no point polishing a *urd. If you want double glazing, for goodness sake make sure that it's hardwood timber framed, otherwise you could knock ?40K+ off the value of the typical ED Victorian semi.

[womanofdulwich]

all well having timber in a period house but in a purpose built flat or say a wates town house then upvc dg will not devalue it.

[red devil]

womanofdulwich Wrote:

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> all well having timber in a period house but in a

> purpose built flat or say a wates town house then

> upvc dg will not devalue it.

The OP quoted a 3 bed Victorian house in her example, my comment about uPVC devaluing a period property was in direct reference to that, not new build...most new builds thesse days come with uPVC anyway, therefore the devaluing argument doesn't really apply, and they tend not to be single glazed as all new builds have to conform with stringent Building Control requirements for thermal heat loss.