I have a (I think) healthy mistrust of double glazing sales people to tell me the truth, but I know that you random people on a bike forum will give me good advice.

Our double glazing is about 20 years old I think. As you can see from the photos, on a cold day I’m getting a bit of condensation in the bedroom, and it certainly feels cooler near the windows than elsewhere in the house.

They are lovely units that still seem to be in good condition, but I guess window tech has moved on?

Is there a trustworthy resource for researching windows to help me narrow down the choice and figure out how much to pay? Can someone just tell me what to get? I know that once I start getting quotes I’m going to be absolutely baffled by the options and price range.

I really don’t want to shell out £1000s and have windows that look worse and perform only slightly better than the ones I already have, so reassure me that this is worth doing please and help me through the minefield!

I was talking to the guy who makes my [wooden] windows and he was saying that the tech in the glass has moved on in the last 5-10 years – by how much I don’t know.

You could just replace the glazing units if you thought it would help but if they’re pretty thin ones then you might need new frames also.

Are yours uPVC? Mine were replaced last year from attractive-looking wooden windows (some of which had warped and there was daylight) to dg mostly in the same style but looked worse aesthetically. Heating is only on once a day and there is no condensation which is great.

Used a local company, no hard sell and were good to deal with.

My house had double glazing from the 80s which had blown really badly and I’ve replaced it with quite expensive decent quality new windows in the last couple of years, and you can still feel that it’s a little colder nearby than it is in the rest of the house.

I mainly changed mine for aesthetics but I was hoping for some efficiency improvement and honestly it’s not really noticeable on the bills or the feel of the house.

Gut feel is that financially it will never pay for itself. I suppose if your windows were drafty that would be a different matter. Mine were just ugly and had condensation inside them from the seals failing.

Do they actually seal still?  Next time it’s windy, light a match and blow it out (or use an incense stick if that’s your thing) and hold it near the seal to see if anything’s blowing in.  All the windows upstairs in our house developed gaps after 15 or so years.  I think the hinges weren’t lubricated, which made them stiff, and opening them put strain on the pivots. They they became slack so there was too much play, and they didn’t seal.

New hinges can be fitted yourself as long as you have two people – but tie a rope around the window and your waist in case you drop it!  It’s quite a fiddle.  You can also replace the rubber seal around the edge but there might be one on the frame and the window as well.

My daughter’s room was always freezing, but I changed the hinges and now it’s way better.  The gap was not even credit-card thickness.

@cinnamon_girl, they’re wooden and suit the house really well 😞 I’ll do some investigating into replacing the glazing units @sharkbait but really no idea whether that would just be doing half a job?

We have a well-insulated house and modern double glazing but we still get some condensation like you have. In fact, I think it would take some pretty hardcore DG to not be colder than solid external walls (simply because solid walls will retain heat for much longer than glass). I assume argon-filled treble-glazing would probably just about do it, but I am sure that would be very spendy.

Bear in mind that your bedroom will be full of lots of very moist air as you use it for some 8+ hours every day.

I think, financially, you’d be better off buying a dehumidifier if you want to avoid condensation and potential for black mould.

Do they actually seal still?

TBF, if they didn’t seal well, there would probably be no condensation (or at least less near the edges) as the ventilation would wick it away.

if the frames are sound and the double glazed panels arent blown, i’d look at getting them refurbed with new seals etc.

we replaced the windows in the older part of the house (sounds grand; just pre-extension…) last year.

They were double glazed aluminium, but 40 years old. No vents, 14mm thick etc. They streamed in the mornings at times like these, and the rooms were – despite heating, window vac, dehumidifier, ventilation etc – getting the odd patch of mould.

The new windows are aluminium, 24mm thick, with vents etc. And there is literally no condensation at all. And no mould. Is it warmer? Possibly subjective. But it feels better.

Had a few quotes; mostly around the same price. All local companies, no national chains.

Can I tell you after our bathroom window is replaced on Friday?

It, and the landing, are the last 2 to be done in the house. One frame was reglazed on the advice of the supplier/installer, but there is a clear draught coming through the bathroom window so that’s getting a new frame too.

Reglazing was about £150, new UPVC frames and glass about £600 I think. We’re in Dorking, so likely to be paying a bit of Surrey tax on that, but we’ve been happy with Dorking Windows advice, supply and aftercare.

Used another local firm at our last house and I wouldn’t go near them with a shitty stick, despite good reviews.

Keep my house warm! How much will new windows help?

I suspect the answer is “Not as much as spending the money on [your heating fuel]”

We recently re-sealed our wooden framed windows and doors for just over £90. Fitting was easy but tedious. It has made a massive difference though, the cold draft near windows is massively reduced. Only problem now is the doors are had to lock as the seal puts too much pressure on the door.

When we moved into our house 13 years ago, one of the first jobs we wanted doing was new double glazing. It seemed to let quite a lot of noise in and we had a fair bit of condensation on the inside during the winter.
We had new glazing all round & not a lot changed, to be honest.

You can normally feel if there’s a draft coming through the seals. New seals might help. New panels in the frames might help. Hard to know for sure. You could always get the glass & seals replaced in one room, assess whether it’s made any difference & then either change the rest or just leave as is.

Had all my upstairs done last year, made a big improvement.

But there was an actual gap next to one of the old units, where I could see daylight.

Had all my windows replaced just before Christmas.  Previous windows were 1980s aluminium and the seals had perished and a couple of units blown.  Condensation upstairs in the winter was really bad, with black mould around the edges.  New windows are uPVC with much thicker glazing and there’s basically no condensation now and the house definitely heats up quicker, so they have made a huge difference.

We had new glazing put into identical looking windows. It has made a difference, not as much as the new windows and doors we had fitted elsewhere, but a step warmer. Our windows are not draughty.

We had 2x large (3m x 1.4m), 2x med (1.4m x 1.2m) and a smaller (1.2x1m) glazing change back in 2019 for £1k. 2 people did it all from a scaffold tower, ladders and in-room in under a day. They planed down the beads to allow for a marginally deeper glazing pane and replaced a couple of broken beads. Great value I thought. From Stirling Glass.

The new windows and doors elsewhere have made a big, big difference. I paid for better glass and coloured frames. I got them made and delivered and I fitted myself. 1x large patio doors, 2x windows (1m x 1.2m) was £2.1k or so and I spent another couple of hundred quid on cavity closers, foam, sealant and fixings. Bought from AWM in Yorkshire.

Front door: new neighbour who works as a window fitter installed on a Saturday morning for £150 with my assistance, his wife works at local door and window supplier who made it. Cost £1800 for a Solidoor and sidepanel painted to our colour all round, with upgraded lock and hardware.

We had a smarmy friendly guy from SafeStyle round a few years ago to quote for us. He brought a whole bunch of samples with him and jabbered away discussed the whole process with us in detail.
Some of their glass is coated to reflect more heat inwards or something like that for extra efficiency, he had a little gadget which touched the glass and a bulb lit up when he pressed the button. This showed it was reflecting heat.
It looked like a tiny shonky unlabelled box with a battery hooked up to an LED but I daresay it could’ve some fancy UV measuring tool or whatever.

Anyway, he phoned up his manager and managed to wangle us an amazing deal, 97% off the normal price! Wow!
Only available if we took the deal right that second, without thinking about it.

We went with someone else in the end… not sure why.

SafeStyle

I used to work with the owner’s (then) wife. She was a PA and she came to work in one of three cars depending on her mood – a BMW M3, a Range Rover or a Ferrari. The MD asked her to stop coming in the Ferrari as he was concerned that our clients would think we were inflating our prices just so the directors could all get flash cars.

We had a load of new high performance windows installed last year. We still get a tiny amount of condensation (not enough to run) in the bedrooms when the temps plummet. The windows are covered with close fitting, thick thermal blinds. I put the condensation down to us habitaing the room for 7 hours, and a lack of airflow behind the blind. As soon as the blind is raised the condensation quickly evaporates. I’m ok with that. 

AS well as new glazing units and seals around the opening parts as posited above check the frames are sealed to the building. 20 years ago it was likely that a bead (or two if a posh install) of mastic is all that is between your warm room and the outside.  Nowadays the frames should be surrounded by expanding foam before the trims go on. Good news is that if the trims come off out side easily you can probably retrofit the foam yourself.

We bought new UPVC as the old frames were poorly insulated, units had blown and the installation only fitted where it touched the opening.

We replaced a couple of big bay windows, made a big difference in conjunction with heavy thermal blinds. And me crawling through the subfloor void to fit insulation between the joists…

he was concerned that our clients would think we were inflating our prices just so the directors could all get flash cars.

Were you? 😉

Were you?

Well no, the PA was driving her own car (as she was the wife of the owner of SafeStyle). My MD drove a Volvo estate.

Hoping a window company turns up today to look for a similar situation in our house. One particular kitchen window you can feel the draft through and hear outside sounds when you stand washing the dishes. I’m hoping something other than a new window can be done just from a cost perspective.

I’m hoping something other than a new window can be done just from a cost perspective.

as above, seals and/or hinges are replaceable and often this solves draft and noise issues.

A company that sells windows might not be keen to offer this…
Try a window repair business or even ask some local handy people. Seals are easy DIY, hinges are moderate DIY.
The seals can be bought on eBay, there’s a bewildering array so pull a bit out and match up.

As mentioned above, 2 main aspects: the seal between the opening casement and the frame (see thin possibly rubber seal in OPs photos) effect of hinges also mentioned and the seal between the actual window frame and the house wall, often hidden by architraves/trim. Basically the seals/mastic/mortar etc dry out and shrink back and thus leave a small gap and hence you can get a draught. So not always the double glazing seal or the window, sometimes the detailing. In essence buying new windows Could help in all these areas, but some maintenance attention may also help for less money more DIY;)

Edit: also worth checking seal on the outside, possibly cement band in OPs pic, look for cracks/gaps.

We have a draughty old Victorian house that had 3 poor quality badly fitting windows upstairs with gaps in the opening.  Downstairs there’s a bay and another window which were both single glazed.

They were rotten, noisy, cold so we had them all replaced at huge cost and mess.

My rough estimates were that we could save around £100-150 a year.  Data from the first months bills show this is about right.

If you have a modern well insulated house I’d expect that saving to be much lower.

Basically there’s no realistic payback on full replacement.  However, the house is far warmer, quieter and looks better all round so we’re happy.  I’d say it’s not worth it if chasing bills alone.

I’ve just had my upstairs windows replaced this week. It’s an old edwardian house which never heats up unless the heating is on a lot. The old windows were either single glazed, or old double glazing which had blown. In cold weather, there was condensation on all the windows and I spent a lot of time in the mornings drying it off. The previous owner clearly hadn’t bothered doing this and rot had started on the frames.

We’ve replaced the whole units with uPVC and the difference this morning to the condensation was amazing. None inside, loads of the outside surface. The house is still cold (although it will take days to warm up after dropping to 5 degrees inside during the work), but I’m confident it’s not the windows fault now.  I am not sure we’ll save money on heating as the general heat loss in the old house is so large, but having better windows makes the house feel so much better.

My previous house was modern but which originally had poorly fitted double glazing. I replaced those windows and I saved money over only a few years, but the windows were really the big heat loss of that particular house. You could see the curtains moving when the wind blew.

We’re very sad to see the wood go on an old house. If we had woodern frames in good condition then we’d have been looking at replacing just the panels.

25 year old house with wooded double glazed windows that were well past their best. Swapped out in 2022 for new UPVC windows. The difference is very noticeable, both in how much easier it is to heat the house and how much quieter it is. However…

I suspect the answer is “Not as much as spending the money on [your heating fuel]”

…this is probably true. House looks much nicer now though.

Good news is that if the trims come off out side easily you can probably retrofit the foam yourself.

Can you explain what you mean by ‘trim’ in this context? I’d like to do this on our house as I suspect that a shoddy job has been done.  17 year old house.

Watching with interest. Just signed up to replace my 1980s wooden double glazing with new 28mm vika profile units.

I have been playing with my FLIR Cam and the difference between the modern upvc units on my extension and the original wood frame unit is mega on the heat loss via the FLiR so I can’t see why the new windows won’t make a major difference.

My wood frames are rotten though …. Not bad for 40+ years though.

Quotes ranged from 4k to 13k for similar looking 28mm double glazed or similar profiles tilt/turns with the largest window needing a toughened pane.

The 4k ones had some grim looking frames when playing with them so we went with the 6k as they came with vika frames

How good are you at DIY… 

Fitting windows isn’t all that hard (I’ve since found out) . 

We got ours done years ago. We were probably fleeced somewhat. 

A guy I work for was a salesman for a while. He could offer substantial discounts off the list price before he called the office. As long as they got the job with some margin. The office didn’t care much. 

You should be able to calculate objectively the heat loss for a ‘best possible’ replacement window and for your current windows.

A quick Google found this article –

https://www.h2xengineering.com/blogs/calculating-heat-loss-simple-understandable-guide/

But at expect more searching will get better sources of info including how the type of glass impacts performance.

I have similar windows to you in my house, mine are air tight and my working assumption that replacing them is not economically justified by any fuel saving. Plus on eco grounds on need to consider energy used in manufacturing new windows. If cared for wooden window frames have an almost infinite life, not sure if that is true of UPVC frames.

I have yet to do the formal calculations, on my to do list.

As a basis for calculations, estimates I see say 25% through roof, 35% through walls and 25% through windows.

They don’t state what the baseline is – but assume 25% is from poor single glazed to top quality double.

Take your gas bill, knock off the summer months as a baseline for hot water and cooking and look at 25% of the remainder as your starter for best possible savings.  That would be extremely optimistic so run it again at 10% saving and that’s your bracket to look at for deciding on the financial part.

Something like that…

And me crawling through the subfloor void to fit insulation between the joists…

This is a job I now kick myself over. Half our floors are too low to get under – and yet we did not have the money when we renovated that area after we moved in – to do the floors now will be a pain…

The front half of the house though is on my ‘maybe I need to go caving’ list…but it wont be pleasant as most of it is about a 30-50cm space, on sand, to the joists above…

How would you get down there?

I’d love to.get under ours, there’s a good 80cm but no acces. I’d have to make a hatch in the wall outside the house.

How would you get down there?

I’d love to.get under ours, there’s a good 80cm but no acces. I’d have to make a hatch in the wall outside the house.

Umm, cut a hatch in the floor? That’s what I did.

I replaced secondary glazed double glazing with state of the art tripple glazing about ten years back. Yes it made a difference but nowhere near as much difference as any of the following: insulating the walls on the inside, insulating under the floor between the joists, insulating the roof to a higher standard. In terms of money saving PV and solar thermal had longer pay backs than insulation but faster than windows.

When I did the pay-back calculations not including my own labour everything paid back within 11 years except the tripple glazing which was probably never.

Ten years on energy prices have increased and things paid for themselves faster than expected, and we’ve benefitted from a house with much less condensation, a more uniform temperature and much reduced temperatures in Summer.

Can you hire, borrow or buy a cheap FLIR camera to see if the windows are your points of heat loss?

the roi on replacing double glazing purely from a money-saving perspective is non-existant. Even replacing old single-glazed windows with double glazing has a return period of somewhere around 25 years, so at best thats cost neutral, the couple of quid a year you’d save with triple glazing over double woudln’t even pay the interest on the cost you’re spending