When I look at the Cathedral in Durham, over 800 years old and still lots of original woodwork, I know upvc will not last that long. Real wood has a look and feel that cannot be replicated, both UPVC and MDF prove that so nature knows best.
Double Glazing or not?
- Thread starter KieranJW
- Start date
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Woody2Shoes
Impressive Member
I agree that - properly designed, made and maintained - conventional timber windows are great, and much better than plastic for all sorts of reasons. The only sticking point is that - in my understanding - building regs force the use of double (not single) glazing to get a suitable U-value of thermal performance. Using DG units in timber frames is what I'm assuming the OP wants to do (and/or will have to do to conform to Part L of the build Regs) and the points I was making are in that context.
clogs
just can't decide
what about triple glazing....?.
I believe the Skandies have been using that for years...
I believe the Skandies have been using that for years...
Inspector
Nyuck, Nyuck, Nyuck!
My house has triple glazed, coated and gas filled PVC windows. Warm/cool and quiet, (I see clogs slipped in a mention). There is no more single glazed here, old house having added a second pane, and double glazing is used in new builds in the cheaper homes. As for longevity there are some companies making thermal break aluminium framed windows but they are harder to find and somewhat more money, not as bulky looking though so let in more light. Getting wood that is of high quality even here is difficult at best and linseed oil paint is special order from specialty companies and is two or three times as much to buy. Have no idea how long the paint will be available before being legislated out. Besides one company say they use linseed oil from Sweden. How environmentally friendly is that?
Pete
Pete
Thanks for all the replies. I've come across the thermal break aluminium windows before and from memory they seemed ok I just like the look and detail of timber so am happy with the longevity of the frames it's just the double glazed units that I am erring on.
I'm just curious why you say the timber is not of good enough quality over here? Pete
Thanks Kieran
I'm just curious why you say the timber is not of good enough quality over here? Pete
Thanks Kieran
Jacob
Pint of bass, porkpie, and packet of crisps please
Not that cold in UK, unless the Gulf Stream stops!
Why would it be legislated out? It's highly durable and relatively low carbon as less energy goes into making it - no alkyd synthesising processes, doesn't need fossil oil derived thinners etc
heimlaga
Established Member
Around here the traditional type of double glazing is casement windows with the outer casement opening outwards and the inner casement opening inwards. Both casements are single glazed and together they form a double glazed unit when they sit in their own rebates in the jambs. Made from good quality pine theese windows normally last somewhere between 50 and 250 years if properly maintained all depending on how exposed the facade is to the weather. Made from oak they seem to last indefinitely.
I don't know thy Brits seem to believe that double glazing per definition must be made with those short lived sealed units.
I don't know thy Brits seem to believe that double glazing per definition must be made with those short lived sealed units.
John Brown
Freeloading Social media influenza
I think it's because our houses are already too small, and having inward opening casements would further reduce the space.
Jacob
Pint of bass, porkpie, and packet of crisps please
I think it's because DG is a relative novelty still - it only got going in the 60s when plastic windows started replacing wood and never evolved far. No tradition in other words and anyway our climate is nowhere near as cold as Finland or Canada.
Would like to see photos of your in and out openers - sounds like a good idea!
Jacob
Pint of bass, porkpie, and packet of crisps please
Inward opening common in France - made possible by having tall narrow sashes which fold back into the window reveal and hence take up no space. They have outward openers too but as solid or slatted shutters un-glazed.
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I was chatting to the fitter (an excellent self employed fitter - I have fitted windows before) who did my two front windows this summer. I commented that the payback time between A and A+ rated windows was several decades (way longer than the windows would last) on the prices I'd been quoted and he agreed, saying also that a problem with many he'd come across was that the sealed units weren't actually the rated to the level the vendors had quoted for anyway. I asked what he thought about triple glazing and he said a total, utter waste of time in this Country - the units are made to fit standard double glazing frames (4mm - 20mm -4mm) so any any possible advantage of three layers of glass is lost by the gaps being too small.
I wonder where I live if it would make sense to have inward opening windows and outward opening doors.
RobinBHM
Established Member
Double glazing is a no brainier in terms of thermal efficiency.
U values:
single glazing 4.2
good dbl glazing 1.2
triple glazing 0.7
as a comparison:
modern flat roof 0.18
cavity wall 0.24
single glazing in a modern, draught proof house will suffer condensation
The air next to a single glazed window will feel cold - as the glass face will be similar temp as outside - it will even create droughts making the effect feel greater.
U values:
single glazing 4.2
good dbl glazing 1.2
triple glazing 0.7
as a comparison:
modern flat roof 0.18
cavity wall 0.24
single glazing in a modern, draught proof house will suffer condensation
The air next to a single glazed window will feel cold - as the glass face will be similar temp as outside - it will even create droughts making the effect feel greater.
Jacob
Pint of bass, porkpie, and packet of crisps please
But not in terms of saving. Rule of thumb is that 20% of heat is lost through SG windows, halved if DG. 10% of your bill. For me about £100 p.a. DG would be a complete waste of money
https://assets.publishing.service.g...37/DECC_factsheet_11.11.16_GLAZING_LOCKED.pdf
Not if there is a normal (essential) level of ventilation and insulation. I've insulated all the walls with 100mm Kingspan between studs so the inside air RH is nearly always above ambient levels. I get a bit on very cold days but have a condensation drip catcher in the cills, draining to the outside. DG plastic get condensation too and often have similar detail
The whole interior is as dry as a bone usually, including bathrooms and kitchen. Bedroom windows get misty if closed on very cold nights
True-ish, but not much of an issue and curtains fix it at night. We have close fitting roller blinds on some of them
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Inspector
Nyuck, Nyuck, Nyuck!
Mostly because all the good stuff, old growth, is exported. Often as logs so there isn't even the added value of cutting it. The second and third growth is okay for construction lumber. The stuff from the Northern forests is small and full of knots including the old growth.
Pete
Inspector
Nyuck, Nyuck, Nyuck!
The British climate is basically like the West Coast of Canada, where I am from. Nothing is built with single glazing there anymore unless it is a barn, garage or some other unheated building. It's all double glazing there.
Oil based paints were legislated out for the most part ages ago because of VOCs so unless there is something chemically different about the linseed oil paint I don't understand it is always going to be a niche product and the nearly $200Can/100pounds a gallon plus shipping will keep it there.
Pete
Inspector
Nyuck, Nyuck, Nyuck!
He might say differently if it was sub zero for 4 months or more a year like it is here.
The glazing and frames are thicker accordingly. They don't use the same frame for both double and triple glazing here.Pete
sometimewoodworker
Established Member
I can comment on longevity sound and comfort. My windows were changed 45 years ago they are mostly aluminium thermal break units with 2 wood units.
1) Sound reduction is significant, I have a railway 30 metres from my back windows and after the IGU’s were fitted don’t notice a train going past, before a train stopped conversation.
2) longevity of IGU’s, currently at 45 years no noticeable change, will they ever (in my lifetime) need replacement? Only time will tell.
3) comfort, only an i*d*i*o*t would ever want single glazing. It’s not just the heat loss, though that makes a difference, it’s the fact that after installing IGUs there were no more cold floor level drafts during winter so the heating was turned down and it was more comfortable. Also never having condensation running down the inside of the windows.
Are IGUs a requirement for double/triple glazing? Absolutely not, as if you look at some countries you will find double and triple glazing using single sheets of glass, but you have to get the design right to allow moisture to escape and that isn’t usual or ever done in the U.K. as IGUs avoid all of that.
Sorry - just seen this so am late to the party. I've been conversing directly with Kieran not realising this thread existed.
Most of us know that double glazing units fail because the primary and secondary seals break down over time - generally due to sunlight damage.
Triple glazing does add thermally to the mix and has that advantage but is largely, otherwise, a marketing con in the UK. It isn't that cold to need them, the units are heavy and more expensive to produce, in standard form they do not contribute that much more to noise reduction and, worst of all, they have twice as many primary and secondary seals as double glazing and are, therefore, far more prone to failure. All glazing units are ticking time bombs but triple glazed units tick rather louder than double glazed ones. The bomb simply hasn't gone off because they are relatively new.
Most people have uPVC because they are cheap to produce and install and maintenance is cheap and easy. The average person doesn't want to spend several weeks each decade up a ladder painting them or paying somebody else to do it. Wooden windows enjoy a bad press because so many of them in new builds are cheap, shoddy quality and let draughts in. Nice wooden windows look great in the right property. Aluminium windows, especially the modern ones are fantastic on account of their low profiles and look. Thermal breaks are essential though and many old aluminium windows fall down because they don't have the break and are thus inefficient and cold.
I cannot see any obvious upsides to single glazing aside from purity (which I can appreciate). Were I to move, I wouldn't entertain a house (for very long) with single glazing. Secondary glazing makes some difference but the air gaps between the panes are not thermally efficient. 16mm in air or 12mm in argon with super warm space bars is about as good as you can get.
Not that I do it now, but the business I once owned advised domestic customers and changed tens of thousands of failed glazing units in all types of frames.
Most of us know that double glazing units fail because the primary and secondary seals break down over time - generally due to sunlight damage.
Triple glazing does add thermally to the mix and has that advantage but is largely, otherwise, a marketing con in the UK. It isn't that cold to need them, the units are heavy and more expensive to produce, in standard form they do not contribute that much more to noise reduction and, worst of all, they have twice as many primary and secondary seals as double glazing and are, therefore, far more prone to failure. All glazing units are ticking time bombs but triple glazed units tick rather louder than double glazed ones. The bomb simply hasn't gone off because they are relatively new.
Most people have uPVC because they are cheap to produce and install and maintenance is cheap and easy. The average person doesn't want to spend several weeks each decade up a ladder painting them or paying somebody else to do it. Wooden windows enjoy a bad press because so many of them in new builds are cheap, shoddy quality and let draughts in. Nice wooden windows look great in the right property. Aluminium windows, especially the modern ones are fantastic on account of their low profiles and look. Thermal breaks are essential though and many old aluminium windows fall down because they don't have the break and are thus inefficient and cold.
I cannot see any obvious upsides to single glazing aside from purity (which I can appreciate). Were I to move, I wouldn't entertain a house (for very long) with single glazing. Secondary glazing makes some difference but the air gaps between the panes are not thermally efficient. 16mm in air or 12mm in argon with super warm space bars is about as good as you can get.
Not that I do it now, but the business I once owned advised domestic customers and changed tens of thousands of failed glazing units in all types of frames.
pgrbff
Established Member
I seem to remember Historic Scotland looking at properly maintained timber versus PVC and I think the timber came out better. I don't think they looked at single over double-glazed.Double glazing vs Single glazing.
- Participants
- KieranJW
- ian33a
- Start date11 minutes ago
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KieranJW
New member
UKW Supporter
11 minutes ago
Hi,
Just read your message about the glazing by a door. I was interested in the 16mm reference to the gap between panes.
I have had a couple of customers now having windows made with Single glazing. I have done a reasonable amount t of heritage repairs and have always preferred the single glazing.
In the next year or so I will be exnteding my house and when I do I would like to replace all of my existing Pvcu windows with wooden windows using linseed paint and am deliberating on single glazed vs double glazed as my main reason for doing wooden windows is that if I do them once I should not have to replace them in my lifetime whereas I notice most people are changing pvc after around 20 years due to them looking tired.
I have read that secondary glazing is better for sound insulation and the bigger the gap the better but the thermal insulation isn't as effective as argon filled etc.
This leaves me wondering if I still go ahead as I dont want the hassle of replacing failed units.
I have fitted secondary glazing for two customers in past employment but the company did it with perspex. Apparently it was effective but never found out the longer term result.
I also though that if a dessicant can somehow be fitted in the gap it should reduce the moisture issue.
I have heard of a chinese double glazing unit that can be refilled (and I assume resealed) but never found out the name.
Any advice or discussion would be appreciated.
Back in the 90's I discovered that in Japan they were manufacturing a sealed unit that was I believe less than 10mm thick, possibly even 8mm. One pane had dimples and was sandwiched with the second pane with the tiny area between them a vacuum. It was a long time ago so I'm sure the details are wrong but it was a suitable alternative for historic buildings. It was very expensive and possibly available through Pilkington.
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