condensation on new double glazed windows...

[dkh]

We got new upvc double glazed windows fitted to the front of our house this week.

My wife is convinced that all our condensations problems on windows would disappear (we had pretty bad condensation on the old single pane sash windows)

However this morning we noticed that the windows in our bedroom were a bit (not enough to need wiped down) steamed up (say bottom 15-20% of each pane)

There was no condensation on any other of the new windows but there was a bit on each pane in our bedroom (6 panes).

Is this just due to the moisture from our breath during the night? Is it fair to expect zero condensation on the windows, should we contact the DG company..

I did google a bit on this but most posts referred to moisture condensation between the panes which is not what we are experiencing.

--dkh

[John Laird]

Some condensation on DG is to be expected. To eliminate it completely, you would need better insulation around the frame (it's conduction through that which leads to the glass getting cold enough for moist air to condense out). I think some makes are better than others in this respect.

I've also had a couple of DG windows fitted this summer. On the first cold night, I was alarmed to see condensation along the bottom of each panel, which wasn't on the inside. I was pondering the likelihood of both units having failed so soon, when it occurred to me to open a window and stick my hand out. The moisture was on the outside (as it often is on your car windows). The DG unit was obviously allowing the outer pane to get very cold.

[Uno Hoo!]

Condensation forms, of course, when damp humid air comes into contact with a cold surface. If the inner pane of your double glazing is cold, and humid air contacts it, then you will get condensation. The condensation will be exacerbated by lack of ventilation.

So a few questions to ask: Why is the inner pane cold, where is the damp air coming from, and is there any ventilation in your bedroom (eg an open window)? If your house is cold - then the inner pane will be cold. If you keep all the windows closed (and your bedroom door closed) then there is a lack of ventilation. Certainly there is a lot of moisture in exhaled breath - but is your house damp as well? Do you have, for example, a tumble drier that vents into the house rather than through an outside wall? Did the window fitters have to do any re-plastering that is now drying out? I have double glazing and occasionally, if the weather is very cold, there is a small amount of condensation on bedroom windows in the morning (right at the bottom) - at this time of year, however, none at all.

Kev

[The Natural Philosopher]

Even DG is not a perfect insulator. Its just BETTER.

Sounds like you have a very humid room - try a little ventilation in it.

[borgmaster]

Buy a dehumidifier, problem sorted without opening windows and letting cold air in.

[Andrew Gabriel]

But you haven't said how to repair the resulting dished floorboards, plaster which has come away from shrunk laths, etc. Far better to ventilate the house properly.

[Dave Fawthrop]

| In article , | "borgmaster" writes: | > Buy a dehumidifier, problem sorted without opening windows and letting | > cold air in. | | But you haven't said how to repair the resulting dished | floorboards, plaster which has come away from shrunk laths, | etc. Far better to ventilate the house properly.

But ventilation costs money to heat up the cold incoming air. Best to reduce ventilation as far as practicable.

[chris French]

In message , Dave Fawthrop writes

Well yes and no. Houses need ventilation, it's more a question of getting the right amount of ventilation in the right places.

[Ian Stirling]

Naah. Go closed cycle. Just electrolyse the output from the dehumidifier, add lots of plants and light, a charcoal scrubber, and you're golden.

[Uno Hoo!]

I always wake up with a headache if I don't have a window open!

Kev

[Steve]

Gabriel)

Check fo CO ( carbon monoxide ) as soon as possible.

[Dave Fawthrop]

| In message , Dave Fawthrop | writes | >On 08 Oct 2005 16:29:58 GMT, [e-mail] (Andrew Gabriel) | >wrote: | >

| >| In article , | >| "borgmaster" writes: | >| > Buy a dehumidifier, problem sorted without opening windows and letting | >| > cold air in. | >| | >| But you haven't said how to repair the resulting dished | >| floorboards, plaster which has come away from shrunk laths, | >| etc. Far better to ventilate the house properly. | >

| >But ventilation costs money to heat up the cold incoming air. | >Best to reduce ventilation as far as practicable. | >

| Well yes and no. Houses need ventilation, it's more a question of | getting the right amount of ventilation in the right places.

Yep 2 square inches in the kitchen and bathroom, plus a catflap in the hall, plus a tiny amount between the old sill and new sill of out double glassed windows (which I deliberately leave there) plus 9sq inches for the old central heating boiler (soon to go) works fine for us. But we do not smoke.

[Bob Martin]

I've run a dehumidifier for the last 15 winters with no ill-effects. We had awful condensation problems before that, but none now.

[jacob]

If you want de-humidifying the best thing is single glazed sash windows. They condense a lot which then drains down and out to the outside via the gap at meeting rails and at the bottom sash staff bead junction. Double glazed and draught proof windows keep humidity in and although there may be slightly less codensation on the window glass itself (it being warmer than a single glazed window) there will be more condensation in other parts of the buildng sometimes resulting in damp walls, mould patches etc. If there is inadequate ventilation there will be more condensation on the DG windows than you would have had with SG windows, due to the higher humidity levels. One (stupid) answer to this prob is 'the de-humidifier' - an item which was virtually never heard of until double glazing and it's probs emerged. A more sensible answer is to open the windows a bit, and keep a window-leather and bucket handy to wipe off condensation.

cheers

Jacob

[Uno Hoo!]

Doesn't matter where I am - in a hotel or staying with relatives. If the bedroom window is not opened to let fresh air in then I wake up with a headache.

Kev

[chris French]

In message , [e-mail] writes

Even when we replaced our old draughty wooden windows (they had louvre vents that wre very draughty...) with UPVC DG we didn't get more condensation. A little bits sometimes, esp. on the bedroom windows, but nothing worth wiping off, certainly it never pooled at the bottom like before.

I guess replacing all the windows, doors etc. and other gaps could leave a house with a ventilation problem.

But yes I agree proper ventilation is important. Other than humans (and their pets) kitchens and bathrooms are the main sources. and extractor hood/fan in the kitchen deals with that, as does one in the bathroom. Our humidistat operated one worked well.

[borgmaster]

You must have bought a dehumidifier the same time as me Bob. I to have had over 15 years of condensation free winters with no ill effect to the fabric or structure of my property. Added benefit is that the water produced can be used in steam irons without the iron scaling up. I wonder if anyone who suggests that dehumidifiers can cause the problems they say have empirical evidence to proof their comments.

[<me9]

That echoes my experiance. They aren't cheap to run though, and mine can only cope with 4 people in residence. any more and it's on continuously.

It's saved quite a bit on paint for window frames too. As a result I've still got one or two wooden ones, and one even single glazed - although that ips planned to be replaced.

It was bought originally after an attack of mould on an outside wall. There's been no sign of mould since.

[Uno Hoo!]

My goodness - it dries the outside of the house as well? ;-)

Kev

[dkh]

In synonypis then ... it would appear that i dont have much to worry about...

Ive spoken to a work colleague who experiences the same and he claims the airflow around the base of the panes is not as good leading to small levels of condensation.

-- dkh