UK windows double-glazed but dodgy?

frankwest12345 · 08-14-11, 07:58 AM

I have a large expanse of south facing windows that are eleven years old and double-glazed with approx 20mm gaps between the panes. However, they seem very reluctant to let any heat in during the summer (which is fine as the house is cool with all the windows closed) and happy to let it out in the winter which is bloody cold when its get below freezing (on the top of a windy hill as well). I can't see any markings on the glass but wonder if they have been put in the wrong way round (ie the inside pane should be outside), if one side has any kind of special treatment?

The windows are in perfect physical shape so I am not inclined to replace them but secondary glazing may be an option. I am going to superinsulate the northern side of the house which only has a couple of small windows before the next winter as well as add insulated floor layer and carpet rather than the current vinyl tiles but would be interested to hear if anyone has experienced the same problem in similar era houses.

AC_Hacker · 08-14-11, 09:29 AM

Quote:

Originally Posted by frankwest12345

I have a large expanse of south facing windows that are eleven years old and double-glazed with approx 20mm gaps between the panes. However, they seem very reluctant to let any heat in during the summer (which is fine as the house is cool with all the windows closed) and happy to let it out in the winter which is bloody cold when its get below freezing (on the top of a windy hill as well). I can't see any markings on the glass but wonder if they have been put in the wrong way round (ie the inside pane should be outside), if one side has any kind of special treatment?

The windows are in perfect physical shape so I am not inclined to replace them but secondary glazing may be an option. I am going to superinsulate the northern side of the house which only has a couple of small windows before the next winter as well as add insulated floor layer and carpet rather than the current vinyl tiles but would be interested to hear if anyone has experienced the same problem in similar era houses.

My guess is that the windows are fine, but you have infiltration issues with your house.

Are you familiar with the 'blower door test'? A special door is fitted into an external door opening in your house and a positive or negative pressure is applied to the house. Meters are used to measure how far from a perfectly sealed house, is your house. If the blower door is used in winter weather in conjunction with a thermal imaging camera, you can see where cold air is leaking in.

Daox had a thread here on EcoRenovator where he described a poor man's blower door, which consisted of turning on all the exhaust fans at the same time and wetting your hand to feel around suspicious areas for air in-migration.

...probably a lit incense stick would do it too.

I bet 15 cents U.S. (which is becoming worth less every day) that infiltration is your biggest problem.

Best of luck...

-AC_Hacker

Ryland · 08-14-11, 11:30 AM

They could be Low-E glass that has been put in backwards, but if it was new glass it would have had a big sticker on it saying "this side out" and the chance of it all being put in wrong is pretty slim.
The chance that it was put in poorly and not sealed is really good, I install counter tops in houses and I see alot of doors and windows that are not installed correctly, holes that if it wasn't for the poorly fitted trim you could stick your hand in the gap around the window.
If a window is not installed well and sealed tightly around it then it doesn't really matter how good the window is, it will be cold and drafty.

frankwest12345 · 08-14-11, 02:38 PM

That is what I don't understand, I am on a hill with some heavy gales on occasion and there are no drafts coming in thru the windows, in fact I have been surprised on occasion when I poke my head out to check the weather (sound insulation is also great) to find it so fierce. All the seals etc are fine and no misting (these are eleven years old). About the Low E windows, could be that as I think there were a lot of Eastern European building workers doing the grunt work back then and may be they couldn't read English!

THe neighbours bought their houses new and they had issues with things like poorly fitted doors and bricks cracking due to frost, so it sounds like there were some idiots at large.

strider3700 · 08-14-11, 02:42 PM

the previous owners replaced the windows on my house. Good windows with horrible install jobs.

I didn't often feel the draft but they always felt cold. When I removed the trim I found they weren't shimmed, had a bit of pink fiberglass jammed in and that was it. sprayfoam and caulking has gone a long way on making them reasonable.

Ryland · 08-14-11, 11:24 PM

Just because you can't feel a draft doesn't mean that air is not leaking in, in my house the air leaks we have come in around the floor joists, drafts under the floor and we get cold spots around our light switches in the partition walls in the inside rooms of the house, air is moving half way across the house to find a hole to get in! that is why air sealing is so important, your house is a maze of air pockets and in some way or another they connect.

Quest · 08-16-11, 10:32 AM

Hello Frank:

I concur with most other posters here. You may probably have 2 issues here at-play:

(1) drafty/leaky house. A blow-door test is the only way to find out (creating a vacuum inside your house, and then check all cracks/seals/seams, windows, etc. for air leaks.

(2) it's not uncommon to have low-E double-pane glass installed incorrectly. I have indeed seen this happened before(we too, plagued by lousy installers here who couldn't read English properly). Unfortunately, it's a bit more involving to find out if yours is indeed installed incorrectly. Granted, if it's not too involving, see if there's a mean for you to reverse the suspected window for 1 season and see if that solves the problem?

Slightly off the record, still relevant to the low-E glass: we here in PNW recently had some sightings that low-E glass windows reflection caused neighbour's house vinyl exterior siding to melt, and a lawsuit is to follow...

Q.

08-14-11, 07:58 AM	#1
frankwest12345 Lurking Renovator Join Date: Aug 2011 Location: Swindon UK Posts: 13 Thanks: 0 Thanked 0 Times in 0 Posts	UK windows double-glazed but dodgy? I have a large expanse of south facing windows that are eleven years old and double-glazed with approx 20mm gaps between the panes. However, they seem very reluctant to let any heat in during the summer (which is fine as the house is cool with all the windows closed) and happy to let it out in the winter which is bloody cold when its get below freezing (on the top of a windy hill as well). I can't see any markings on the glass but wonder if they have been put in the wrong way round (ie the inside pane should be outside), if one side has any kind of special treatment? The windows are in perfect physical shape so I am not inclined to replace them but secondary glazing may be an option. I am going to superinsulate the northern side of the house which only has a couple of small windows before the next winter as well as add insulated floor layer and carpet rather than the current vinyl tiles but would be interested to hear if anyone has experienced the same problem in similar era houses.

08-14-11, 11:30 AM	#3
Ryland Master EcoRenovator Join Date: Mar 2009 Location: Western Wisconsin. Posts: 913 Thanks: 127 Thanked 82 Times in 71 Posts	They could be Low-E glass that has been put in backwards, but if it was new glass it would have had a big sticker on it saying "this side out" and the chance of it all being put in wrong is pretty slim. The chance that it was put in poorly and not sealed is really good, I install counter tops in houses and I see alot of doors and windows that are not installed correctly, holes that if it wasn't for the poorly fitted trim you could stick your hand in the gap around the window. If a window is not installed well and sealed tightly around it then it doesn't really matter how good the window is, it will be cold and drafty.

08-14-11, 02:38 PM	#4
frankwest12345 Lurking Renovator Join Date: Aug 2011 Location: Swindon UK Posts: 13 Thanks: 0 Thanked 0 Times in 0 Posts	That is what I don't understand, I am on a hill with some heavy gales on occasion and there are no drafts coming in thru the windows, in fact I have been surprised on occasion when I poke my head out to check the weather (sound insulation is also great) to find it so fierce. All the seals etc are fine and no misting (these are eleven years old). About the Low E windows, could be that as I think there were a lot of Eastern European building workers doing the grunt work back then and may be they couldn't read English! THe neighbours bought their houses new and they had issues with things like poorly fitted doors and bricks cracking due to frost, so it sounds like there were some idiots at large.

08-14-11, 02:42 PM	#5
strider3700 Master EcoRenovator Join Date: Dec 2008 Location: Vancouver Island BC Posts: 745 Thanks: 23 Thanked 37 Times in 30 Posts	the previous owners replaced the windows on my house. Good windows with horrible install jobs. I didn't often feel the draft but they always felt cold. When I removed the trim I found they weren't shimmed, had a bit of pink fiberglass jammed in and that was it. sprayfoam and caulking has gone a long way on making them reasonable.

08-14-11, 11:24 PM	#6
Ryland Master EcoRenovator Join Date: Mar 2009 Location: Western Wisconsin. Posts: 913 Thanks: 127 Thanked 82 Times in 71 Posts	Just because you can't feel a draft doesn't mean that air is not leaking in, in my house the air leaks we have come in around the floor joists, drafts under the floor and we get cold spots around our light switches in the partition walls in the inside rooms of the house, air is moving half way across the house to find a hole to get in! that is why air sealing is so important, your house is a maze of air pockets and in some way or another they connect.

08-16-11, 10:32 AM	#7
Quest Apprentice EcoRenovator Join Date: Feb 2011 Location: Canada Posts: 109 Thanks: 13 Thanked 13 Times in 11 Posts	Hello Frank: I concur with most other posters here. You may probably have 2 issues here at-play: (1) drafty/leaky house. A blow-door test is the only way to find out (creating a vacuum inside your house, and then check all cracks/seals/seams, windows, etc. for air leaks. (2) it's not uncommon to have low-E double-pane glass installed incorrectly. I have indeed seen this happened before(we too, plagued by lousy installers here who couldn't read English properly). Unfortunately, it's a bit more involving to find out if yours is indeed installed incorrectly. Granted, if it's not too involving, see if there's a mean for you to reverse the suspected window for 1 season and see if that solves the problem? Slightly off the record, still relevant to the low-E glass: we here in PNW recently had some sightings that low-E glass windows reflection caused neighbour's house vinyl exterior siding to melt, and a lawsuit is to follow... Q.