Window condensation new double glazing

thehamo

So

We got new double glazing windows in a couole of years back. As soon as cold weather comes in were gettimg condensation at the bottom of the windows. It's inly about an inch if even, personally I don't mind but the wife has me mithered to get it sorted. We have trickle vents in the windows. Each external wall was warmboarded a good few years back. In terms of ventilation theres prob little else other then the vents. Any ideas? She wants tonget one of those air filtration systems up in the attic but they cost a fortune I personally don't see the point!

Pkiernan

thehamo wrote: »

So

We got new double glazing windows in a couole of years back. As soon as cold weather comes in were gettimg condensation at the bottom of the windows. It's inly about an inch if even, personally I don't mind but the wife has me mithered to get it sorted. We have trickle vents in the windows. Each external wall was warmboarded a good few years back. In terms of ventilation theres prob little else other then the vents. Any ideas? She wants tonget one of those air filtration systems up in the attic but they cost a fortune I personally don't see the point!

In between the panes means a bad seal, should be covered by warranty.

thehamo

Pkiernan wrote: »

In between the panes means a bad seal, should be covered by warranty.

Sorry tis on outside but indoors if ya get me. Not inbetween the panes per se

Seth Brundle

The condensationnis on the room side if the glass? Is the room ventilated properly?

listermint

Moisture on Windows from room side means the moisture can't escape.

Were the window frames tape sealed? If no look to do it


Also what ventilation does the room have. Type and position

fred funk }{

Too much moist damp air in the room and the glass is the coldest surface in the room so that's where it condenses.

You either have to ventilate more or stop creating the excessive moisture. I'd opt for both.

fatbhoy

fred funk }{ wrote: »

Too much moist damp air in the room and the glass is the coldest surface in the room so that's where it condenses.

You either have to ventilate more or stop creating the excessive moisture. I'd opt for both.

What about windows (and frames) that have a thermal break? Shouldn't that keep the interior window/frame surface not so cold, thus minimising condensation?

I have this problem too in my house: old aluminium frames prone to condensation on the interior surface during cold weather. I was hoping that replacing them with modern ones (with thermal breaking) would mitigate the condensation problem. By the way, I know very little about all this, but I read somewhere about this thermal breaking thing.

listermint

fatbhoy wrote: »

What about windows (and frames) that have a thermal break? Shouldn't that keep the interior window/frame surface not so cold, thus minimising condensation?

I have this problem too in my house: old aluminium frames prone to condensation on the interior surface during cold weather. I was hoping that replacing them with modern ones (with thermal breaking) would mitigate the condensation problem. By the way, I know very little about all this, but I read somewhere about this thermal breaking thing.

Thermal break means nothing if the Frame is not fitted correctly. Ive yet to see a window installer that is properly fitting Air tight Tape around frames at install.

most if not all use small cell expanding foam which is not good enough. some even use just silicone !

Lumen

listermint wrote: »

Thermal break means nothing if the Frame is not fitted correctly. Ive yet to see a window installer that is properly fitting Air tight Tape around frames at install.

I was talking to one supplier of high-end windows at the home thing at the RDS yesterday who said "we use foam unless you specifically ask to use tape, whatever you prefer".

Which means that people who don't know any better (and who don't know to ask) are getting expensive windows fitted with inferior air tightness to save a relatively tiny amount of effort.

From what I've read PU foam isn't airtight unless it's 2.5" thick.

listermint

Lumen wrote: »

I was talking to one supplier of high-end windows at the home thing at the RDS yesterday who said "we use foam unless you specifically ask to use tape, whatever you prefer".

Which means that people who don't know any better (and who don't know to ask) are getting expensive windows fitted with inferior air tightness to save a relatively tiny amount of effort.

From what I've read PU foam isn't airtight unless it's 2.5" thick.

It should always be both, Foam for the gap. and tape to stop the flow.

Its incredible they dont do this as par for the course because it only makes their own windows look '****e' ultimately

zl1whqvjs75cdy

Sorry to hijack a bit here but I am in the process of scoping new windows for the gaf. What should I specify at install? Tape and foam? I'm going to be on site when the job is being done too because it's too important to take their word for it that the job was done correctly.

Lumen

donkeyoaty0099 wrote: »

Sorry to hijack a bit here but I am in the process of scoping new windows for the gaf. What should I specify at install? Tape and foam? I'm going to be on site when the job is being done too because it's too important to take their word for it that the job was done correctly.

Have a look around Youtube for videos by the companies that sell the sealing products.

For instance

https://www.youtube.com/watch?v=G-rD_bfoSQ4

Wartburg

It doesn´t matter how good you´re sealed and taped around the window. The condensation will still appear on the pane. It clearly indicates that the content of moisture in the room is too high and/or the room temperature is too low. Every window (triple glazed, passive, made of "futureproof materials") is still weaker on the insulation performance than the surrounding walls. That means the surface temperature on the inside of the window is lower in comparison to other parts of the building. That´s why you´ll see condensation on the window pane first.
Take attention to the humidity level and the room temperature, to get the condensation sorted and wipe existing condensation off with a cloth.
The good thing about condensation on a window pane is, that this indicator for a bad indoor climate is clearly visible. If you struggle with condensation on your walls, you just can see it the moment where mould has been developed already.

listermint

I covered that in ventilation.

But bad fitting amplifies condensation. You cannot say it doesn't matter with a straight face.

It's a collective piece of the puzzle..

Lumen

Condensation isn't necessarily caused by unhealthily humid indoor air.

I just checked my bedroom (after two showers in the ensuite) and there is condensation all over the single glazed, wood framed 1980s window. Room temp is 21C, RH is 53%, outdoor air temp is about 6C.

Now that RH is on the high side, but only a bit. Normal healthy range is 40-50%.

In this case the condensation could be easily solved by upgrading the windows to raise the glass temperature (and frame) temperature above 11C. The sealing of the windows is partly to stop cold air getting in and cooling the glass & frame, but mostly to stop humid air getting into voids in and around the frame and causing interstitial condensation and mould.

Conversely, dropping the indoor RH from 53% to 40% (with better ventilation or a dehumidifier) would only drop the dewpoint from 11C to 7C, and I'd still get condensation on cold nights.

edit: actually I don't know there's anything unhealthy about high RH other than the condensation risk. There are many parts of the world where outdoor RH of 60% is low (the US has 10 cities that average over 70% RH outdoors all year round), and they're not all keeling over with respiration diseases, are they?