uPVC windows cold

[Davey]

We have uPVC double glazing fitted throughout the house. In the cold weather you can feel a draught coming from the windows which is likely due to the cold air from the windows mixing with the warm air as the seals are all making good contact.

Is it my misguided perception that you shouldn't feel cold air with this type of glazing? I always thought uPVC glazing was supposed to prevent the cold from penetrating the windows and making the room cold? Or do we just have really poor glazing installed?

Thanks

[Mike Clarke]

It can't prevent the cold from penetrating, just reduce it - or to be pore precise you reduce the amount of heat being lost through the window.

The consolation is that you would have a colder draught if it wasn't double glazed.

[Tim Watts]

My uPVC (very modern) are extremely warm - the frame is warm and the inner glass pane is surprisingly uncold.

Have you got the trickle vents open?

[Dave Liquorice]

Misguided correct. Double glazing will just reduce the amount of heat lost through the glazing unit so the inner pane is far warmer than it would be on a single glazed window. You will still get some cooling of the air next to the glass and this will form a slight draft falling from the window. But nothing like you would have with single glazing. You don't say where you are but it has been pretty cold for most of the UK recently with some places being damn cold.

We have had ice form on the inside of the double glazing here on occasion, admitedly on windows also behind two pairs of curtains.

It might be worth a quick check of the seals. Trap a narrow strip of paper in them and it should be held in place and not to too easy to slide along.

[Ronald Raygun]

Perhaps you are warming the inner pane. Is there a radiator below it?

[Tim Watts]

No CH right now. And that observation is in direct comparison to some older (30 years) ali DG frames with 4mm thermal break.

[Davey]

Based in west Shropshire. It has been down to -12deg C a couple of times, but the cold from the windows is something I've noticed when it's been warmer than this.

I was concerned that with the house being Persimmon built in 2000, the quality of the DG would be well below average as the rest of the build is.

Yep, Sunday morning there was an inch of ice at the bottom of the bedroom window. I can't remember ice being on the window since my folks got rid of their single glazing in the late eighties.

Will give that a go thanks.

It also goes to show the insulative qualities of good curtains. We have a bay window in the lounge and usually only close the venetian blinds, but the last week or so we've been closing the curtains which are in the lounge, rather than around the bay IYSWIM. If you put your hand behind the curtains, you can really feel the temp difference.

[The Natural Philosopher]

Even the best DG is ten times worse than a well insulated wall.

[PeterC]

Last winter, I noticed how cold the air was behind the closed vertical blinds when opening them in the morning. This was unexpected, as vertical blinds seal about as well as a picket gate. Having been given an assortment of curtains, I found that som fine net was just the right drop and sufficient to do all 4 front windows. There's a very noticeable difference now when opening the blinds. I suppose that the net just slows down the convection across the window.