[Metallo]

Hi,

My home is 12 years old, I bought it two years ago and the first winter the problem was already evident, but now is getting worst.

I have 12 windows + 2 french windows all with the same issue.

I took some pictures in order to provide a better idea.
The condensation is inside, not in between the glasses.
Also ice formation is unavoidable at the bottom due to the water leaking in the rail.

I keep humidity under control, usually between 40%- 50% with dehumidifiers/humidifiers according to season.

I believe the problem is the sealing but you are the experts here.

I am good in DIY, however I never worked with windows therefore I have to learn.

I rely on your good advice as I want to solve this problem next spring :thumbsup:

Thank you!
Alex

 

[gregzoll]

Your house is too air tight, which means you do not have enough air movement. What temp do you keep your heat on, and what is your Relative Humidity reading right now along with inside & outside temp. If you want to be able to read various areas in your place for temp & rh, grab one of these http://www.radioshack.com/product/index.jsp?productId=11361230 and two extra sensors. That will give you four areas to read around the house, to see what is going on.

Does not surprise me with you being in Canada, that you are seeing a dew point at that level, causing the windows to sweat. I only get a little condensation on my windows at along where the bottom of the aluminum meets the glass, and that is only because we have black out/insulating drapes in our place, so not much air movement allowed around the windows.

 

[firehawkmph]

Met,
turn your humidifier all the way down till the windows dry up. Once the windows don't show any condensation, turn your humidifier up a little each day until you just start getting condensation along the bottom of the sash. Then back it off a little from there. Also, make use of exhaust fans, etc.
Mike Hawkins

 

[Metallo]

Hi,

We use also black out/insulating drapes in the bedrooms, during the night in this period we have about 60% humidity with 63 F.
Downstairs in the living room, early in the morning the humidity is 45% and temperature about 59 F, the condensation is in fact slightly inferior.
During the evenings we have 68 F and 45% humidity, condensation is very limited then in the living room.

I am sure that what you are saying about the humidity is true, however, I am sure there is also an issue with the sealing, particularly I suspect the desiccant.

As I said, the house is 12 years old an next spring I want to look at this issue by removing at least one window and see how it is, but I need advice.

What are the main things I should pay attention to when removing a window?

Any particular sealing I should use?
How about the desiccant, can I replace it?
Do I need any special cleaning stuff for the frames of just soap and water?

@Mike, at the moment we do not use the humidifier, but the humidity is dropping every day, it is very dry outside and we expect to start using it in the next two weeks once it goes down to 30%.

Thanks
Alex

 

[gregzoll]

There is your problem. 59 in the living room, 63 in the bedrooms, but medium humidity, means that you need to keep your heat constant, and get some air exchange going. At 45% average rh, you should not have condensation, but that right there is showing that you are hitting the dew point, due to keeping your day time temps too low.

At night, it is okay to lower down to say 65f, then bump back to say 68 to 70 for the rest of the time. I finally decided this year to set the thermostat from 9:30 at night to 6:00 in the morning at 65f, then from 6am to 9:30pm keep it set at 68f. My humidity levels stay around 51-56 and no problems.

As for the black out curtains, they are meant for daytime use, not night time, but they do help to keep the cold air from coming off of the glass surface of the windows, to help maintain a comfortable temp level.

 

[oberon]

There is no issue with sealing or with desiccant. What you are seeing, based on the pictures, has nothing to do with seal or disiccant.

You have condensation on your windows because the glass temperature is below the dew point.

Dew point temperature is the transition between evaporation and condensation. Dew point is defined as saturation vapor density, or actual humidity, or simply, 100% relative humidity. Go above the dew point temperature and you have evaporation, go below it and you have condensation.

Dew point is "fixed" depending on the moisture in the air. "X" moisture level will always equal "Y" dew point.

In other words, if the air in your home holds 5 grams moisture per cubic meter of air then the dew point is 0 degrees C. Ten grams moisture per cubic meter and the dew point is at 11 degrees C. These numbers are totally independent of the temperature in your home, or the temperature outside, or any other temperature. Dew point is based on moisture level.

Most folks will refer to relative humidity when dealing with moisture issues simply because we use RH all the time while we rarely consider actual humidity. Relative humidity is the actual vapor density divided by saturation vapor density - or - the percentage of moisture in the air versus the maximum amount of moisture that the air can hold at a specified temperature.

In order to stop condensation from forming on the surface of your windows you must:

lower the dew point by removing moisture from the air, or
warm up the window surface to a temperature above the dew point, or
do some combination of both.

Your curtains are blocking air flow to the windows at night. No airflow equals cold glass, cold glass equals condensation issues.

Do your windows have condensation during the day or when the curtains are open?

 

[mknasa dad]

Here's a guideline for your humidity level.

http://www.rlcengineering.com/win_chart.htm

I assume that the glass is not Low-E, right?

You have to lower you humidity level, as well as get some air circulation. If you have any ceiling fan, try turning it on in reverse.

 

[gregzoll]

You have to lower you humidity level, as well as get some air circulation. If you have any ceiling fan, try turning it on in reverse.

Did you not read what they posted? Their humidity levels are already low, and a ceiling fan is not going to solve the issue, this is a condition that can be solved by bringing up and keeping the ambient air temps higher than they have them, along with bringing in fresh air.

Canadian homes are notorious of being more air tight than their Down South counterparts south of their border.

 

[mknasa dad]

Did you not read what they posted? Their humidity levels are already low, and a ceiling fan is not going to solve the issue, this is a condition that can be solved by bringing up and keeping the ambient air temps higher than they have them, along with bringing in fresh air.

Canadian homes are notorious of being more air tight than their Down South counterparts south of their border.

No, it is not an ambient air problem. It is a humidity/conditions/product issue.
A ceiling fan WILL help out by circulating air in the rooms.
Read post #4. They use black out/insulating drapes, thus inadequate air circulation to the glass.

What is the outside temp???

 

[gregzoll]

No, it is not an ambient air problem. It is a humidity/conditions/product issue.
A ceiling fan WILL help out by circulating air in the rooms.
Read post #4. They use black out/insulating drapes, thus inadequate air circulation to the glass.

What is the outside temp???

Go back and read Posts 1 & 4. And then take a look at their location posted under their name. You are just repeating what I stated and others about poor circulation, which is a part of the problem, but the biggest issue is that their home is too air tight, and does not have enough exchange of inside & outside air.

 

[hammerlane]

They use black out/insulating drapes, thus inadequate air circulation to the glass.

I agree with that. If I leave the family room and kitchen blinds down during the night, I will have condensation on almost 80% of the surface of each of those windows in the morning. If I leave the blinds up at night, the only condensation on the windows is around the perimeter of the glass. On my current windows, the spacer between the panes of glass is metal. Newer windows now have a less non-conductive material as a spacer that helps cut down on heat transfer.

 

[Windows on Wash]

I think Oberon's post most completely sums up the issue at hand.

The issue is Dew Point and whether or not the Relative Humidity levels are outside the recommended range is another question. 50 is probably pushing it but the real formative reason for the glass getting so cold is the lack of exposure as a result of the heavy drapes.

Open them up or lower the humidity level.

 

[gregzoll]

At 43-50, they are actually at the right rh point. They just need to open the drapes, but also keep the temp up higher during the day, than droppin it by a 10 degree dif, while away.

 

[Metallo]

Hi folks,

thanks very much for the huge response :thumbsup:

Yes, you are right it is only a balance temperature/humidity, during the last two days outside temperature went up and condensation disappeared.
Inside humidity is now below 40%, in fact I will have to put on the humidifier to keep it at 45%.

We have the air exchanger which we use but... not abuse as obviously it inputs cold air which triggers the heating.

The critical areas are where the drapes are.
Drapes are essentials to avoid dispersion and protect from the cold, the ones in the bedrooms are fundamentals for what just said and in addition, to keep dark in the morning.
Alternatives would be shutters but I have never seen them in NA.
We have a ceiling fun in the bedrooms

Believe it or not, our bathroom does not have an exhaust fan which I believe is essential to avoid condensation in such an exposed room.

Anyhow, everything looks clear to me thanks to your help :yes:

I will do some test till I will find the right balance.

Cheers
Alex

 

[gregzoll]

You are correct on the exhaust fan for the bath. If there is not one, it is adding to the indoor humidity levels, also allowing condensation to form, due to more moisture in the air, even though your rh may be between 43-55.

 

[woodworkbykirk]

having drapes can cause the problem also.. they stop the heat from getting at the glass so the inside pane of glass is at the same temperature as the room. this can cause the condensation..

i worked on an apartment building 4 years ago installing trim.. at that stage all the units had electric baseboard heat in and running. the owner of the building would turn the heat down to 5 degrees celcius at hte end of the day.. then every mornig the glass was covered in condensation.. he noticed it and was complaining that the windows were leaking and causing the mdf sils to swell. i clearly told him he has to leave the heat at 15 minimum this time of year or its going to keep occuring,