Green Building Forum - new windows or just new glass? Wed, 29 Apr 2026 02:09:23 +0100 https://www.greenbuildingforum.co.uk/newforum/ Lussumo Vanilla 1.0.3 new windows or just new glass? https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2963&Focus=38572#Comment_38572 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2963&Focus=38572#Comment_38572 Tue, 18 Nov 2008 15:32:15 +0000 Peter Clark
Also we had the cavity walls filled a while back, since then, lots of problems with condensation on the edges of the glass (but not prior to the CWI).

I am wondering if, instead of shelling out for new windows, we just replaced the double glazing units - Pilkington K, warm edge, argon fill etc. Would the result be anywhere near good double or triple glazing, does anyone have any idea?

Peter]]> new windows or just new glass? https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2963&Focus=38576#Comment_38576 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2963&Focus=38576#Comment_38576 Tue, 18 Nov 2008 15:59:15 +0000 rogerwhit new windows or just new glass? https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2963&Focus=38581#Comment_38581 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2963&Focus=38581#Comment_38581 Tue, 18 Nov 2008 16:50:33 +0000 tony new windows or just new glass? https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2963&Focus=38834#Comment_38834 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2963&Focus=38834#Comment_38834 Thu, 20 Nov 2008 08:22:44 +0000 CWatters new windows or just new glass? https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2963&Focus=38838#Comment_38838 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2963&Focus=38838#Comment_38838 Thu, 20 Nov 2008 09:22:47 +0000 Peter Clark Posted By: CWattersPersonally I believe ventilation to be more important than anything

That is certainly my belief, as a struggling amateur in all this. So we know we will definitely have to address the humidity in our house by ventilation. I suppose I muddied the waters by mentioning the condensation in the first post, probably because that is the impetus for us thinking about the windows.

I suppose I am really asking in this thread, if we refurbish our windows, including new bang up to date glazing units, how close will we be, thermally, to new double or triple? I don't expect anyone will have a definite answer, but I just thought it might be worth asking. It would certainly be less expensive for the bank account, what about the environmental impact?

Peter]]> new windows or just new glass? https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2963&Focus=38839#Comment_38839 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2963&Focus=38839#Comment_38839 Thu, 20 Nov 2008 09:33:35 +0000 Peter Clark Posted By: CWattersI attribute this to the whole house heat recovery vent system we installed when building it

Thanks CWatters,

We have looked into this also, the main issue is the requirement for airtightness, which is said to be crucial. So it is difficult to justify spending the money on the MVHR, and the airtightness modification, unless we can get it down to 3 air changes per hour at 50 Pascal. But when I approach contractors, no one can guarantee that they can achieve this for a sixties semi with suspended wooden floors.

Any advice on this would be welcome.

Peter]]> new windows or just new glass? https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2963&Focus=38859#Comment_38859 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2963&Focus=38859#Comment_38859 Thu, 20 Nov 2008 15:54:12 +0000 JackyR new windows or just new glass? https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2963&Focus=38862#Comment_38862 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2963&Focus=38862#Comment_38862 Thu, 20 Nov 2008 16:03:23 +0000 Peter Clark Posted By: JackyRwhen spoke to an MHRV company techie about this and other issues (disused chimneys as ventilation ducts), he didn't seem bothered about airtightness

I have had the same experience with companies who install MHRV. But when I spoke to a company who supply the kit, who I have reason to trust, they said it was not worth the bother and expense, unless airtightness was 3 air changes or less per hour at 50 pascals.

I don't KNOW who to believe, but the latter advice seems more believeable, if less convenient.

Peter]]> new windows or just new glass? https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2963&Focus=38863#Comment_38863 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2963&Focus=38863#Comment_38863 Thu, 20 Nov 2008 16:14:32 +0000 JackyR
But the Q remains, what sort of ventilation is efficient (in cash & energy) to solve condensation probs, given one needs SOME.]]> new windows or just new glass? https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2963&Focus=38865#Comment_38865 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2963&Focus=38865#Comment_38865 Thu, 20 Nov 2008 16:29:33 +0000 Peter Clark Posted By: JackyRBut the Q remains, what sort of ventilation is efficient (in cash & energy) to solve condensation probs, given one needs SOME.

I started another thread 'What type of ventilation to retrofit', I am hoping to achieve some clarity.

Peter]]> new windows or just new glass? https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2963&Focus=38873#Comment_38873 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2963&Focus=38873#Comment_38873 Thu, 20 Nov 2008 19:02:35 +0000 CWatters Posted By: Peter Clark
Posted By: CWattersI attribute this to the whole house heat recovery vent system we installed when building it


Thanks CWatters,

We have looked into this also, the main issue is the requirement for airtightness, which is said to be crucial.

It might have an effect on the energy saving aspect but seems not to be a problem for ventilation. We have two chimneys with stoves but they aren't room sealed types. The company that made our other wooden windows also fitted trickle vents in them without us asking for them. We keep these closed but they aren't air tight and we didn't make any special effort to design an air tight house although it was wet plastered which helps.

The vent system has two fan speed controllers so we can choose if air goes in or out of any leaks - anyone know which is worse? We currently have both on the lowest speed setting as it's winter. We turn it up in summer to get a higher air change rate.]]> new windows or just new glass? https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2963&Focus=46312#Comment_46312 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2963&Focus=46312#Comment_46312 Thu, 05 Feb 2009 11:24:44 +0000 Peter Clark
I am still wondering how reasonable to renovate my aluminium windows, rather than buy new’uns. The prices for triple make my eyes water.

Posted By: Peter Clark
Posted By: ralphdI used some foam in a can to fill the cavities & fixed the problem.

Hi Ralph,

You mean you filled the cavities in the PVC frames?

It has crossed my mind to try this with our aluminium frames, but I dismissed it as a mad idea. Can you say how you did this? Were the frames in place in the building?

>Posted By: Peter Clark
Posted By: howdytomif your alloy frames are a one piece extrusion, ie no thermal break,

then the alloy will still conduct the heat around any infill insulation.

you could drill 6mm holes then after foaming fit grommets

Posted By: Peter ClarkThanks Tom,
The frames have a thermal break in, i believe, so maybe filling with something insulating would not be possible, or useful?
I am having trouble visualising it, I have never seen a window frame other than installed into a wall, so i don't understand how they are constructed.

peter
]]> new windows or just new glass? https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2963&Focus=46343#Comment_46343 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2963&Focus=46343#Comment_46343 Thu, 05 Feb 2009 13:26:34 +0000 ralphd With aluminum frames (even with thermal break) this probably wouldn't help much.]]>