Aluminium Windows - Condensation?

renov8

I have a query about excessive condensation on new aluminium windows, perhaps someone here might be able to offer opinions or advice.

I don’t want to go into a long explanation of the problem (I can if someone wants me to). Essentially, we got new aluminium windows installed in a renovated house last year. The windows are from a reputable company and they installed them. We noticed condensation on the frames along the bottom once the weather got cooler, it gets worse when the weather is colder. The company had an engineer take a look and he concluded it was excessive moisture in the house. I took him at his word but am questioning this as I suspect there is a problem with the windows i.e. they are not sufficiently thermally broken. Is there any way I can test the temp of the frame to give an indication of how cold they are? They feel cold to touch. Any help appreciated.

Markcheese

Infra red thermometer will give you the temperature ( point it at window frame,press the button ) , well it may give you the temp of the film of condensate on the frame but there shouldnt be much difference...

renov8

Markcheese wrote: »

Infra red thermometer will give you the temperature ( point it at window frame,press the button ) , well it may give you the temp of the film of condensate on the frame but there shouldnt be much difference...

Ok, thanks, sounds interesting. I was thinking that some form of thermometer that makes contact with the window frame would not be accurate due to heat transfer etc. I need to ask a friend in the trade if he has access to such a thing. I could always dry off the condensation before taking the temp.

Dardania

Another way to look at it would be to measure the relative humidity in the room, the dry bulb temp in the room, and if condensation appears, it means the window frame surface is below the dewpoint. Would address the window supplier's suggestion that the house is too damp...

Try this website: http://dpcalc.org/

draiochtanois

This post has been deleted.

Dardania

draiochtanois wrote: »

This post has been deleted.

Very difficult to say - it's extremely subjective - like saying what length is a piece of string.

RH changes as temperature changes, and it can range up & down over a day. So say the room is 21C, you wouldn't be surprised to see RH from 40%-70%, depending on the house construction...

renov8

Dardania wrote: »

Another way to look at it would be to measure the relative humidity in the room, the dry bulb temp in the room, and if condensation appears, it means the window frame surface is below the dewpoint. Would address the window supplier's suggestion that the house is too damp...

The engineer that the window company sent did measure the relative humidity and the dew point. He said he was satisfied that the levels were high and the cause of the condensation, rather than any issue with the windows. I have not seen the report as the company wanted to charge me half the cost of it, which was fair enough.

But the reason i'm not fully satisfied with this is that when we are not in the house, condensation does not appear. It seems to me that if the house has moisture in it, it is there regardless of whether we are inside or not (I know that humans being there causes more with cooking, exhaling etc). My main issue is that the frames feel cold to touch. I can't imagine PVC being as cold which leads me to suspect that the alum frames are not properly thermally broken. But i'm not an expert so am just guessing.

I should add that the temp outside seems to affect the degree of condensation on the inside. I have noticed this in the bedroom as I can check it first thing in the morning. There are always two of us and it appears to be worse on colder mornings, which would suggest the temp of the frame is going up down.

Dardania

renov8 wrote: »

The engineer that the window company sent did measure the relative humidity and the dew point. He said he was satisfied that the levels were high and the cause of the condensation, rather than any issue with the windows. I have not seen the report as the company wanted to charge me half the cost of it, which was fair enough.

But the reason i'm not fully satisfied with this is that when we are not in the house, condensation does not appear. It seems to me that if the house has moisture in it, it is there regardless of whether we are inside or not (I know that humans being there causes more with cooking, exhaling etc). My main issue is that the frames feel cold to touch. I can't imagine PVC being as cold which leads me to suspect that the alum frames are not properly thermally broken. But i'm not an expert so am just guessing.

I should add that the temp outside seems to affect the degree of condensation on the inside. I have noticed this in the bedroom as I can check it first thing in the morning. There are always two of us and it appears to be worse on colder mornings, which would suggest the temp of the frame is going up down.

Maybe get one of these:
http://www.ebay.ie/itm/HYDROPONICS-DIGITAL-LCD-THERMOMETER-HYGROMETER-GROW-TENT-ROOM-HUMIDITY-PROBE-UK-/262224014277?var=&hash=item3d0dc4ebc5:m:mS6Q8KKdwKsM3UqBrUQEUSg

And start putting the values for temp and RH into the dpcalc.org website when you see condensation - that will tell you what the surface temp of the windows are below at least...

Take this example - if your room temp is 18C, witha RH of 70%, the dew point is 12C. If condensation were present on the frame, it would mean that the frames are below the dew point.



Keep an eye on what the outdoor temp is also - as you note if it's worse when its colder outside, it does point to coolth from outside cooling down the frame.

By the way, aluminium will generally feel cold to the touch - it's a conductor of heat, so if it is colder than your hand, it will absorb heat pretty readily. That doesn't mean anything in particular is wrong with the window...unless it's bridging to outside

Questions:

- what U value are the frames (sold as)?

- what is your ventilation situation in the affected rooms?

renov8

Dardania wrote: »

Maybe get one of these:

And start putting the values for temp and RH into the dpcalc.org website when you see condensation - that will tell you what the surface temp of the windows are below at least...

Take this example - if your room temp is 18C, witha RH of 70%, the dew point is 12C. If condensation were present on the frame, it would mean that the frames are below the dew point.

Keep an eye on what the outdoor temp is also - as you note if it's worse when its colder outside, it does point to coolth from outside cooling down the frame.

By the way, aluminium will generally feel cold to the touch - it's a conductor of heat, so if it is colder than your hand, it will absorb heat pretty readily. That doesn't mean anything in particular is wrong with the window...unless it's bridging to outside

Questions:

- what U value are the frames (sold as)?

- what is your ventilation situation in the affected rooms?

Thanks for the reply and the suggested temp/RH monitor. I had no idea they were so cheap, are they fairly reliable/trustworthy?

As for your other questions, I checked the window specs and it seems the profiles are from Smart in the UK. They are Alitherm 800. That company's website suggests they have a u-value of lower than 1.6 when used with the correct double glazing. Curiously, the guy that did our BER said that some of the windows in the property had a u-value or 2 to 2.7.

In terms of vents, we have standard 100mm vents in each room in the house, put in when renovations done. However, the engineer pointed at they were down low and should be up high. The builder never advised us of this and suggested we could put them high or low.

Water John

Yes, the vents should be high up. No use down low if you think about it.

We put on a porch over the front door. It used to be drowned wet in there. We then tiled the floor and it cured it. Handyman, said he had seen this before. I don't know why it worked.

renov8

Water John wrote: »

Yes, the vents should be high up. No use down low if you think about it.

I can see the logic of this now and it's on the list of things to rectify. Problem is it was one of those rushed decisions that the builder presented us with and there was no advice that higher was better.

ammc

I've condensation on my own windows this 4 years now. What I do know is that window supplier/builder will always blame humidity rather than their windows/installation/build. Like yours, it's really noticeable in the cold weather as we've had lately.

Some things that may lead to cold bridging is do your windows have vents or weep holes in them. They say the chambers inside the frames are independent of each other but the barrell of my window handle goes to the external chamber and the handle is freezing these mornings. Also, would you have a steel lintel over your windows as this is what your windows could be secured to and again conducting cold.

I got the lend of a fluke infrared thermometer at one stage and got temps of room @ 18c and PVC frames at anything between 5c-11c depending on the night. Also got same temps from a digital multimeter. I do suspect a build or installation issue, but trying to prove it is another thing.

I hope you get it sorted because I know how annoying it is.

JonathonS

If your friend can get hold of a thermal imaging camera it will give you a much better indication of whether the bottom of the frame is significantly colder than the sides and top. If this is so it may indicate an issue with the thermal break in the frame, or with the installation method.

Is there a cavity in the wall?
If yes how wide is it?
Is the volume of condensation similar is all rooms?

renov8

JonathonS wrote: »

If your friend can get hold of a thermal imaging camera it will give you a much better indication of whether the bottom of the frame is significantly colder than the sides and top. If this is so it may indicate an issue with the thermal break in the frame, or with the installation method.

Is there a cavity in the wall?
If yes how wide is it?
Is the volume of condensation similar is all rooms?

Couple of questions there and the from the poster above. Here goes:

Windows have no trickle vents and I don't think there are weep holes, definitely not in the bedroom windows anyway, which are tilt and turn. No steel lintel.

Cavity in the wall: No. Solid block work.

The volume of condensation is not the same in all rooms. For example, our 2 year old sleeps in the box room. There has been on condensation on that window all winter. We sleep in the main bedroom which is still actually quite small. Same size window as box room and lots of condensation there. Sunday night/Mon morning was frosty outside and there was a lot of condensation, reached almost half way up the frame and there it was about 6 inches high on the glass. Last night, a little milder outside, no condensation this morning.

I am going to try a couple of things that were suggested here: record room temp and RH to get a series of readings on the dew point; try to get a thermal image of the frame; and try to get an infrared temp reading. Will report back to the thread.

renov8

So my temp/RH gauge arrived yesterday. There was a lot of condensation this morning on our bedroom windows as it was quite cold out last night. I had the gauge in the bedroom at about 2 metres off the floor, not sure if this is an appropriate position?

My readings were 17.4 C and 71% RH which gives a dew point of 12. I did not take a reading for outdoor temp but accuweather tells me it was 0, there was frost on the ground. So, do I take from this that the frames of the windows and the actual glass itself was lower than 12? Would anyone care to advise what these figures are suggesting i.e. have we too much moisture with insufficient ventilation OR have we an issue with cold frames? Or both? I can obviously take more readings and report back here again. By the way, on previous mornings when it was not as cold overnight the condensation in the bedroom was greatly reduced.

JonathonS

71% RH is high, but that figure will reduce to c 55% as your home heats up to 21-22c. Around 50-55% would be the norm. It is likely that the condensation is a result of cold bridging from the solid wall to the internal part of the window frame. Two occupants in a bedroom will produce c1L of moisture overnight. The solution is to remove the moisture by improving the ventilation, perhaps via Positive Input Ventilation.

Dardania

See this thread where BryanF suggests that one needs the windows to be better than 1.2 u value to keep internal dewpoint below 12C

http://www.boards.ie/vbulletin/showpost.php?p=98820568&postcount=19

Interesting that your dew point is exactly the same - it sounds like you have not very well performing windows, and normal levels of humidity.

What you can do is try keep the temp above 18C or maybe even 18.5C at night. I have started setting it to 18.5C in my home lately, mainly because I have a 6 month old that I am irrationally terrified of freezing, but I notice that occasionally the rads have been on over night - not too often maybe 1 night in 5 or 6...

BryanF

Op what is the u-value of the glass and separately what is the u-value of the frame? Are these 3G units?

renov8

The U-Value of the frame, according to the manufacturer's website is less than 1.6. I do not have a u-value for the glass but can see if I can find that out. I don't know what you mean by 3g?

Edit: The frames are Alitherm 800 by Smart Systems but they were not the company that supplied and fitted them.

selous

My folks got new windows about 4 years ago, and the surrounding internal walls are a disgrace, all mouldly and condensation runs down them when it's really cold outside, even the window board gets wet (you can see the tide lines) I knocked away the internal plaster and what was behind was that expanding foam in a crap state, mustn't be weather resistant stuff, I removed as much as I could and put sand & cement in and plastered it up again, looks better but next winter will tell if it worked.

The company shut up shop about 2 years ago, so much for the 10yr warranty, they were in operation for about 15yr before they got the windows so thought they were reputable.

renov8

A little less condensation this morning but still substantial. Dew point of 10 with temp of 17.5 and RH of 63. Not sure why the RH is less this morning.

MicktheMan

renov8 wrote: »

Not sure why the RH is less this morning.

The cold weather, i.e. the external air is 2 to 3 times (maybe more) dryer than the internal. You will see this reverse when it gets milder.

renov8

MicktheMan wrote: »

The cold weather, i.e. the external air is 2 to 3 times (maybe more) dryer than the internal. You will see this reverse when it gets milder.

Not really correct. The outside temp was the same as the night before, all other variables were relatively constant but the RH was 71% the night before as opposed to 63% the night after.

MicktheMan

renov8 wrote: »

all other variables were relatively constant

Not quite. Moisture levels in the house (not just in the internal air but also in the internal structure) would have been lower from one day to the next due to the low external temp.

ch750536

If you have an external building without insulation then if the inside is humid and the outside is cold, you get moisture.

3 ways to solve it.

1. Remove the moisture (not possible if you are growing).
2. Keep the moisture as vapour (warm the air). Not possible if no power.
3. Equalise the temperature (open a window).