Double glazing in existing sash windows

[Teapot74]

Has anyone had it done? Is it expensive? worth it? can anyone rec a company? (we are not listed)

Hi - I had friends did this and I think for 2 large bay windows in an Edwardian House they paid around £10K? I think they used the Box Sash Window Company, but not sure. I think they were very pleased. I would get more than one quote and maybe even look at smaller, companies who might do it cheaper?

We looked at this. You can double glaze an existing sash but the glazing is very narrow and does not meet building regs (I think that is the one). You will get improved heat loss but it won't be as good as proper current double glazed standards, however, the alternative (which is not cost effective) is to rebuild the entire frame and put proper current standard double glazing in. I think either way, its nigh on impossible to recover the any cost of improvement against turning the heating up or buying good thick curtains.

Look at secondary glazing. It will be better for noise insulation as well.

I looked in to this for our sash windows but there wasn't enough window depth. We opted for refurbishment and draught proofing rather than taking out the originals. I'm hoping we've made the right decision. Anything will be warmer than the howling wind that comes through them now!

Oh Dear :( doesn't sound great. thanks though.

We looked into it. It would have been about 20k for our house - 2 bays, 5 others.
Getting a small firm to refurbish the existing sashes to replace brushes, bits of rotting wood, etc and installing unobtrusive secondary glazing was about 4k. And once it was done the temperature in the living room went up by 3 degrees.

I'm sure I've heard of compact double glazing for this that now meets building regs. The sashes can usually be modified to accept the increased depth.

I think its worth it to keep the original, architectural look of an original sash window. Update the seals too and draughts will be eliminated and they will be a lot easier to slide.

There is some good information on the Period Property UK forum.

We looked at refurbishing windows and fitting with slimline double glazing but the cost was only marginally cheaper than the hand built hardwood properly doubled glazed replacements. It's because the cost isn't the materials it's the labour involved.
I love our new windows they look exactly the same as the gorgeous old ones but they make the house soooo much warmer, they are safer & they open
Yes they were expensive and in terms of recouping expense on heating bills alone they are worth it but in terms of overall value of our house they were + we are planning on staying here for 20yrs so it was worth it in terms of our comfort .

We used a small firm and they were fab, highly recommend them, Chapel Lane Sash Windows, they were happy to answer all my questions, no matter how silly they seemed! I love our new windows our house is soooo much warmer chapellanesashwindows.co.uk

Wonkylegs. Roughly how much for a large sash did you pay? If you don't mind me asking.

Just bought a house (project untouched for 55 years). It's in a conservation area so must keep wood sashes (painted white). House is 1860 and has 30 sashes which are currently falling apart (some could be salvaged but circa 1/3 are shot completely).

I've put aside

Ok so we are having our sashes refurbished, painted inside and out and draught proofed at this very moment. So 20 windows (top and bottom sash is one window) is costing us around £11 000. To install slimlite double glazing (we could as windows thick enough), draught proof and paint inside and out came in at around £25 000 and to make new sashes which are double glazed was £40 000. We are also staying here long term but after A LOT of research we couldn't justify the extra cost of installing the slimlite double glazing. There is no way we will recoup that cost in lower heating bills (it's a Victorian detached house - full of breezes and no cavity walls etc) and double glazed units don't last forever - the seals eventually go and need replacing. Also refurbishing the windows gets a special VAT rate of only 5% as the government recognise it as a energy efficiency but installing the double glazing gets full VAT of 20%. It was the draughts and rattling that we didn't like and I can honestly say they have made a big difference and we've not even finished yet.

Posted too soon. Argh

I have put aside £60k for windows (for refurbing those that can be saved and installing slimlite double glazing in the rest).

I'd obviously prefer to spend much much less however we re just outside London so it will all be expensive.

Caco. Thanks. That's excellent info.

Perhaps I won't need to spend quite as much as I thought. That would make a pleasant change....

I do think installing any double glazing will be such an improvement even without cavity walls as most heatloss occurs through windows and roof not thyme walls

Thyme = the.

Has anyone had a quote for Pilkington Spacia, the vacuum double glazing? Because the panes have a vacuum between them instead of gas they are as slim as ordinary double glazing and overcome the problems of other slim double glazing systems. I hear the cost is quite high at the moment because they have to be shipped from Japan, but I wonder how high. I tried to get a quote but it seems my order wasn't large enough for the company to bother with.

MrsF we are south east London so could recommend our people if you like. PM me if you wish. Ours work all over London, so may well come to you.

Mrs F I'd definitely get a couple of quotes, prices varied widely when we did ours. I dealt with Gary at Chapel Lane Sash Windows, couldn't recommend them highly enough 07813329681
Best of luck there's a lot of choice out there !

Subysmum. Thank you for the recommendation! I will have a chat to him as well. So far I have two lots giving me quotes as of today.
Inc Cacofonix recommendation. Thanks to. He was really useful to talk to.

No problem Mrs F, hope you got your windows!