Double vs triple glazing in 2025
Discussion
Hi all
Hand in the air, this is well outside my area of expertise, hopefully the collective has some insight though.
I'm having a new front door fitted, whilst the guys are quoting up, I've being asking them about some other windows i plan to replace in the next year.
I told them i was going to go for triple glazing, supposedly much more affordable now, better energy savings and insulation etc etc.
Three separate companies now have queried me on why i feel this is necessary. They have all said that modern double glazing with Argon filled units and insulated frames are more than sufficient and if they were glazing their forever home they would all go double glazing.
Are they right? None of them could give an indication of the price different between double and triple glazing so i don't have any figures to work with unfortunately.
2000 built house
Currently half timber framed double glazed (original) and half upvc double glazed.
6-7 windows to be replaced.
1 of which is 2.5m x 2.0
Thanks in advance
Hand in the air, this is well outside my area of expertise, hopefully the collective has some insight though.
I'm having a new front door fitted, whilst the guys are quoting up, I've being asking them about some other windows i plan to replace in the next year.
I told them i was going to go for triple glazing, supposedly much more affordable now, better energy savings and insulation etc etc.
Three separate companies now have queried me on why i feel this is necessary. They have all said that modern double glazing with Argon filled units and insulated frames are more than sufficient and if they were glazing their forever home they would all go double glazing.
Are they right? None of them could give an indication of the price different between double and triple glazing so i don't have any figures to work with unfortunately.
2000 built house
Currently half timber framed double glazed (original) and half upvc double glazed.
6-7 windows to be replaced.
1 of which is 2.5m x 2.0
Thanks in advance
I have modern argon filled doublr glazing.
We had ice on the outside of the windows the other night.
Inside was a nice 20.5c according to the thermostat.
Our 7 windows. One bigger than your 2.5m one was about £7k fitted.
We also had front and back doors fitted at the same time. They were £5k
It took 2.5 days to get it all fitted and trimmed and made good.
We had ice on the outside of the windows the other night.
Inside was a nice 20.5c according to the thermostat.
Our 7 windows. One bigger than your 2.5m one was about £7k fitted.
We also had front and back doors fitted at the same time. They were £5k
It took 2.5 days to get it all fitted and trimmed and made good.
Had a full house worth of windows 7 years ago, from memory it was about 10% difference in cost (including fitting into a bare shell) for triple compared to double glassed, glass U value for the triple was a significant improvement on the double, so opted for triple. No regrets, but insulated the rest of the house to a high standard, so the windows and doors were always going to the be weakest element.
I seem to remember when we did the doer upper, double glazing had the worst payback of anything from an energy point of view. Obviously there are asthetic and security benefits, but vs single glazed something like 75 years for recouping energy costs.
We have Argon filled, with black middles. Icy on the outside, warm on the inside.
I'm sure Sarah Beeny mentioned years ago, if you go Triple, it needs acoustic glass. You can achieve similar performance results, if the double glazed unit is deeper than the standard 24mm one installed in most applications.
We have Argon filled, with black middles. Icy on the outside, warm on the inside.
I'm sure Sarah Beeny mentioned years ago, if you go Triple, it needs acoustic glass. You can achieve similar performance results, if the double glazed unit is deeper than the standard 24mm one installed in most applications.
bigdom said:
I seem to remember when we did the doer upper, double glazing had the worst payback of anything from an energy point of view. Obviously there are asthetic and security benefits, but vs single glazed something like 75 years for recouping energy costs.
We have Argon filled, with black middles. Icy on the outside, warm on the inside.
I'm sure Sarah Beeny mentioned years ago, if you go Triple, it needs acoustic glass. You can achieve similar performance results, if the double glazed unit is deeper than the standard 24mm one installed in most applications.
28mm is the standard thickness for upvc double glazing, 40mm for triple. The upvc frames are the same for both you just use a slimmer profile glazing bead for triple.We have Argon filled, with black middles. Icy on the outside, warm on the inside.
I'm sure Sarah Beeny mentioned years ago, if you go Triple, it needs acoustic glass. You can achieve similar performance results, if the double glazed unit is deeper than the standard 24mm one installed in most applications.
Triple glazing can be worthwhile, but it can also be a bit of a white elephant because good double glazing can actually be better than poor triple glazing. Best not to think of it in terms of "double vs triple" but rather in terms of "what U-value is it worth paying for". How that U-value is achieved doesn't really matter.
What a piss poor selection of answers,
You need numbers.
Look at the actual heat losses and do the maths.
The benefits will depend on the amount of glass relative to the other heat losses in the room.
Also whether you're going to have curtains or whatever.
If you're paying someone for the design make them do their job and provide some analysis.
Edit : Kambites makes a valid point, you need actual numbers for the actual double or triple glazing you are choosing, he posted while I was typing.
You need numbers.
Look at the actual heat losses and do the maths.
The benefits will depend on the amount of glass relative to the other heat losses in the room.
Also whether you're going to have curtains or whatever.
If you're paying someone for the design make them do their job and provide some analysis.
Edit : Kambites makes a valid point, you need actual numbers for the actual double or triple glazing you are choosing, he posted while I was typing.
Little Lofty said:
I think from this year new builds need triple glazing to meet the latest regs.
You need to meet the U-value standard defined in the buildings SAP assessment.Whether you achieve this by using triple glazing or double glazing with argon is up to you.
As has been said above, it’s the overall Thermal performance that’s important and relevant for making a valid comparison, not the number of panes of glass and whether it’s filled with gas.
jules_s said:
Elysium said:
Triple glazing isn't used on commercial buildings.
It's a lot of additional cost for very little benefit.
I've just completed a school to stage 4 (latest DFE output spec) and we ended up triple glazedIt's a lot of additional cost for very little benefit.
As has been said its not the number of panes that matters its the thermal performance (u-value) vs cost.
Most of the time in commercial settings double glazed wins, unless you are going for some sort of passive performance specification. I don't build schools, but would not be surprised if the DFE have gone for some sort of 'fabric first' solution.
I like these - triple glazing which uses the exterior glass to seal over the wooden frame so that you never need to repaint!
https://www.vrogum.dk/en/wooden-windows-doors/vrog...
https://www.vrogum.dk/images/pdf/svarre-brochure-e...
For my next house….
https://www.vrogum.dk/en/wooden-windows-doors/vrog...
https://www.vrogum.dk/images/pdf/svarre-brochure-e...
For my next house….
Edited by dobly on Friday 10th January 21:48
OutInTheShed said:
What a piss poor selection of answers,
You need numbers.
Look at the actual heat losses and do the maths.
The benefits will depend on the amount of glass relative to the other heat losses in the room.
Also whether you're going to have curtains or whatever.
If you're paying someone for the design make them do their job and provide some analysis.
Edit : Kambites makes a valid point, you need actual numbers for the actual double or triple glazing you are choosing, he posted while I was typing.
Unless I've misunderstood you literally nobody gets those sort of numbers, nor any sort of 'analysis'. People buy windows based on what they feel (they're draughty/energy bills are high/they look old) and choose on the basis of whichever sales story they like best.You need numbers.
Look at the actual heat losses and do the maths.
The benefits will depend on the amount of glass relative to the other heat losses in the room.
Also whether you're going to have curtains or whatever.
If you're paying someone for the design make them do their job and provide some analysis.
Edit : Kambites makes a valid point, you need actual numbers for the actual double or triple glazing you are choosing, he posted while I was typing.
I should know because I sell them. I'd guess around 70% of people don't even ask me what u-value they're getting, they just want new windows 'because better' and pick out someone with good reviews. The technical aspects fly way over most people's heads (including the sales people).
I'd agree that ultimately it is about u-value v cost, and there are various ways to achieve lower values e.g. different profiles, glasses and gasses, but if you give people too many options they s
t themselves, so a simple double v triple is an easier choice to make.Triple glazing can reduce the heat loss from about 1.8 W/m2K to about half that.
Pretty sure that 1.8 is for modern argonfilled , low E units.
If you've got a lot of glass area, it can be the dominant heat loss in a room, as well insulated ceilings and cavity walls can have u values of 0.2 or less quite easily.
I have about 10 sqm of window in my lounge, the double glazed windows account for about half or 2/3 the heat loss. So potentially a 25% gas saving.
But also better comfort due to a more even temperature across the room and less convection draughts.
It's not going to pay for itself if you're tearing out perfectly good albeit old-spec glazing units, but the extra cost when installing new might be worth looking at.
If you've got windows particularly high up, then maximising their insulation can be very worthwhile.
But a lot of houses are dominated by draughts and heat losses other than the windows.
And some of us shut the curtains when it's cold and dark out
It's easier to justify in a colder climate in a house that's otherwise more efficient.
And I think the price difference is reducing as market share has increased, a lot of triple glazing is chosen for traffic noise etc.
Pretty sure that 1.8 is for modern argonfilled , low E units.
If you've got a lot of glass area, it can be the dominant heat loss in a room, as well insulated ceilings and cavity walls can have u values of 0.2 or less quite easily.
I have about 10 sqm of window in my lounge, the double glazed windows account for about half or 2/3 the heat loss. So potentially a 25% gas saving.
But also better comfort due to a more even temperature across the room and less convection draughts.
It's not going to pay for itself if you're tearing out perfectly good albeit old-spec glazing units, but the extra cost when installing new might be worth looking at.
If you've got windows particularly high up, then maximising their insulation can be very worthwhile.
But a lot of houses are dominated by draughts and heat losses other than the windows.
And some of us shut the curtains when it's cold and dark out
It's easier to justify in a colder climate in a house that's otherwise more efficient.
And I think the price difference is reducing as market share has increased, a lot of triple glazing is chosen for traffic noise etc.
Elysium said:
jules_s said:
Elysium said:
Triple glazing isn't used on commercial buildings.
It's a lot of additional cost for very little benefit.
I've just completed a school to stage 4 (latest DFE output spec) and we ended up triple glazedIt's a lot of additional cost for very little benefit.
As has been said its not the number of panes that matters its the thermal performance (u-value) vs cost.
Most of the time in commercial settings double glazed wins, unless you are going for some sort of passive performance specification. I don't build schools, but would not be surprised if the DFE have gone for some sort of 'fabric first' solution.
We’ve just used it on a commercial building we’re turning over.
Glazing firm said they’re seeing more and more.
Hi all
Thanks all for your comments, very helpful.
I had one of the chaps back this morning and i asked him to bring u-values with him.
He turned up, measured up, and did some calculations on the double vs triple u value for the glazing area.
I didn't see much of the calculation, but the improvement vs the price was small and we agreed it wasn't worth it. So I've gone double glazing
Btw it was about 30% more expensive for triple glazing
Thanks again
Thanks all for your comments, very helpful.
I had one of the chaps back this morning and i asked him to bring u-values with him.
He turned up, measured up, and did some calculations on the double vs triple u value for the glazing area.
I didn't see much of the calculation, but the improvement vs the price was small and we agreed it wasn't worth it. So I've gone double glazing
Btw it was about 30% more expensive for triple glazing
Thanks again
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