Double glazing sash windows

[ZippyFish]

I went for a viewing today and loved the house but it has single glazed sash windows which will need upgrading to double glazed and redecorating the house and adding a dishwasher as there isn’t one at the moment. Can someone help with approximately how much will the cost of this be? It’s a one bed Victorian conversion flat in Dulwich.

Is it a conservation area, whats the road?

You dont have to upgrade the windows unless they are in bad condition, but if you want timber double glazed original windows they will be really expensive. You could get UPVC but depending on whether its a conservation area you might not be allowed, did the nearby properties have UPVC

If the windows & frames are in good condition other than the single glazing, you could always get secondary glazing.

Can't comment on timber, but our recent quotes for mid range timber effect uPVC sliding sashes came in between £1300 - £1500 each inc. vat and fitting, home county

Obviously is depends on size. We changed 2 windows in a flat in a conservation area not far from Dulwich and combined they cost £10k although that was quite a while ago and one of the windows was a very big bay.

London box Sash and Timbertherm are very good.

we paid 1.3k some years ago for one new sash.

If it's in a conservation area you may need planning permission and they'll have to be wood.

It's impossible to quote because it depends on what you opt for.

You can have double glazed glass put into original wooden sashes and have them refurbished to stop drafts and make sure they work properly.
Replacement sashes, wooden and pvc often use springs to balance them and that makes them really difficult to open and close so try to keep the weights if you can.
As a temporary/ semi permanent fox, you can install secondary magnetic pvc glazing on the inside. Costs about £100 per window.

In terms of refurb Vs replacement pre COVID or was about £500 for a new pvc sash and similar for refurbishing a sash and maybe £800-£1000 for a new wooden sash but that was up north. Probably double those numbers now?

We had replacement double glazed sashes put in a couple of years ago on a Edwardian terrrace - around £8k for four windows. We used Sash Restorations Limited (London). They were very good and even checked measurements and details with neighbouring houses as we weren't sure that ours were entirely original - so we have very slim glazing bars which look very different from UPVC and even some of the standard wooden ones available. Our boxes were in good-ish order so it was only the sashes that were needed, but they worked to repair and preserve the details and integrity of the whole unit - they function beautifully look gorgeous.

It has been so worth doing, it's really improved sound warmth and we have maintained the look of the property in a small way. Previously though we had had integral brushes fitted on single glazed sashes (until we could afford double glazing)- this was fine and a lot cheaper (and sometimes recommended on listed windows where you cn't replace with double glazing) for a while, but not as effective. I can't remember the name of the company that did that as it was a while ago, but that was under £500 a few years back - your sashes need to be in good order though.

UPVC doesn't last as long as people think and often fails even though it feels more affordable, it might not be in the long run. (this is clearly a justification as I still can't believe I spent that much on windows - I do love them though).

Thanks all this is very helpful.

Glad you liked the place – Victorian conversions in Dulwich have loads of charm, but yeah, single-glazed sash windows can be a bit of a pain (and chilly!).
For upgrading to double glazing, you’re probably looking at around £1,200–£1,800 per window, depending on size, access, and whether you go for full replacements or sash retrofits. If it’s a one-bed flat, you might have 4–6 windows, so budget £5k–£10k as a ballpark.
Redecorating will depend on how much you're doing yourself – a basic repaint for a one-bed flat might be £1,500–£3k if you get a decorator in.
Adding a dishwasher depends on kitchen layout and plumbing – if there's space in a base unit and plumbing nearby, it could be as little as £300–£500 including the appliance and fitting. If the kitchen needs reworking to make space, that cost will obviously go up.
All in, you might be looking at £7k–£13k-ish, depending on choices and how much you DIY. Worth doing though if the flat’s otherwise right!

I had my single glazed sash windows in conservation area house double glazed. Its not exactly double glazing, but the tradersperson will fit an exact replica pane behind the original. Its around 2k per window inc VAT. My frames had to be repaired too though and repainted, exactly like for like.

@Worsthousebeststreet Would you mind sharing which company you used?

Sorry changed my username since this thread! We used Foulger & Childs in Leighton Buzzard, didn't end up going with the sliding sashes in the end but we were really happy with the company and our lovely new indows

@Worsthousebeststreet thank you!