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Overthinking replacement sealed units

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Midsmartin
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Overthinking replacement sealed units

#503328

Postby Midsmartin » May 28th, 2022, 10:52 am

I could just call our local windows company and ask them to replace some failed, misted up, double glazing units with whatever they recommend. Job done!

But I've started over-thinking it. What is the best/most environmentally friendly way of doing it?

The current windows were installed in 2001. I doubt they are low E. Several units upstairs in our house have failed (on both the N and S facing sides).

Should we replace them piecemeal as they fail, room by room? Or do the whole house while we're at it.

I could:
1) replace just the units, keeping the pvc frames, with new double glazed low E units from our local company.
2) seek out those with the longest guarantee, on the basis that the longer they will last before themselves failing, the better. 10 year guarantees are common. Anglia offer 15 years. These people ( https://www.cloudy2clearwindows.co.uk/2 ... ntee-tscs/ ) say 25 years, but their website is a bit vague about details. I'm inherently suspicious that their windows might be twice as long lasting as everyone else's!
3) Have the failed units 'fixed'. Companies like this https://www.getthemistout.com/category_s/1826.htm claim to have a system to make existing units usable again. This would send less waste to landfill, but would not upgrade glass to low E.
4) Replace the whole frame as well with something better insulated than the 2001 frame. But I somehow doubt the small insulation improvement would outweight the cost of sending the old frame to landfill and manufacturing a new one.

As a complication, we have a large sliding exterior glass door. It hasn't failed, but the room is cold. Partly I think this is due to bad construction - I think there are draughts under the floor and around the frame as well (despite attempts to fill them). I'm inclined to replace this door entirely, but if all the heat is going out around the side of it, there's little point. I think I just have to toss a coin on this one.

Laughton
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Re: Overthinking replacement sealed units

#503442

Postby Laughton » May 28th, 2022, 4:58 pm

I was interested as we have a very large, non opening, double glazed window which now mists up.

Your option 3 sounds ideal (I've been quoted close to £1,500 for a new sealed unit to be fitted) but does having this "repair" undertaken give back the thermal insulation of the original or replacement sealed unit?

I know very little about double glazing but I always thought that the insulation was not just dependent on having two sheets of glass instead of one.

88V8
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Re: Overthinking replacement sealed units

#503495

Postby 88V8 » May 28th, 2022, 8:14 pm

Laughton wrote:I always thought that the insulation was not just dependent on having two sheets of glass instead of one.

It's the air gap.
1" dg units are very good, if you have the rebate depth.

I installed 1" dg units in our wooden sash windows in 1982. When we sold the house in 2012 none of them had misted.
In contrast, perhaps half the units in our wooden conservatory, built for us in 1991, had misted, including some huge units in the roof.
The difference was that my units were face-puttied - albeit not with putty of course - whereas the conservatory was bead glazed. Bead glazing is a botch, as it does not provide an air and water-tight seal around the edge of the units. PVC windows are, in effect, bead glazed so the dg units have poor lifespans.

Three years ago I installed 33 new sealed units in new wooden windows in our cottage. They were bedded and fronted in glazing compound and I expect them to see me out.

V8

DrFfybes
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Re: Overthinking replacement sealed units

#503559

Postby DrFfybes » May 29th, 2022, 9:06 am

88V8 wrote:
Laughton wrote:I always thought that the insulation was not just dependent on having two sheets of glass instead of one.

It's the air gap.
1" dg units are very good, if you have the rebate depth.

V8


My old place had 20mm units in an aluminium frame, 2mm glass with a 12mm air gap. Over the years that changed to 24mm (presumably your 1 inch) and now 28 mm (20mm air gap) is the norm. The thicker the air gap (usually dried Argon gas) the better the insulation).

You can get them custom made with different glass thickesses and/or laminated for noise reduction or security applications, and in these cases the air gap can be reduced to allow them to fit an older rebate down to about 12mm.

Paul

88V8
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Re: Overthinking replacement sealed units

#503583

Postby 88V8 » May 29th, 2022, 10:54 am

Midsmartin wrote:....the room is cold. Partly I think this is due to bad construction - I think there are draughts under the floor and around the frame as well (despite attempts to fill them). I'm inclined to replace this door entirely, but if all the heat is going out around the side of it....

Rather than randomly spending money, perhaps it would be best to find out where the heat is going. A thermal imagining camera will let you do just that. This room, and indeed the whole exterior.
One here https://www.amazon.co.uk/dp/B0728C7KND?tag=georiot-trd-21&th=1&psc=1&ascsubtag=dcw-gb-1295149109746353000-21&geniuslink=true

Or search for Thermal Imaging Camera on eBay ... a random example...https://www.ebay.co.uk/itm/334452257445?hash=item4ddee872a5:g:k1gAAOSwtHZijTIW

When you're done, you can sell it again.

V8


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