Window Condensation

[DigitalAssassin]

Trooper's house thread got my thinking about a current problem we are encountering so I thought I would throw it out here and see if anyone has thoughts...

We moved into an older house 2 years ago (built 1960). Structurally it's in good shape, the only overall problem we have had is extreme window condensation in the winter. Now, I know some condensation is normal with single pane windows, I'm talking enough water that it is rotting the wood frames of the windows. The house itself seems very 'tight' because our energy bills are never bad and the temperature stays very consistent. Humidity in the winter hangs around 60-65%.

We've had a couple of 'professional consultants' out and have received two different suggestions:

1. Get an HRV (Heat Recovery Ventilator).
2. Get new windows (we would need 11 windows).

Both options will run close to $3,000. We can afford to do one of the two right now, but not both.

The presence of condensation is I know a result of the cool temperature of the outside of the window versus the warm temperature of the interior. So, given that the current windows are single pane, wood frame (original I'm sure) windows I'm leaning toward getting new windows. Not only would it potentially resolve the problem, it would increase the value of the house.

However, I'd hate to get the windows and turn around and have the condensation problem again next winter and have to get an HRV or something similar anyway.

Anybody had a similar problem or have any suggestions?

[icky]

You need better air circulation. Consider opening some windows a crack and if you have forced-air heating, run the fan full-time.

It is also possible that your humidity is too high. Do you have a humidifier on the furnace? Is the setting appropriate for winter?

[DigitalAssassin]

No humidifer on the furnance. Initially, it seemed like the humidity was too high but I have a contractor buddy who said for this time of year and in this region that number really isn't bad.

[icky]

Ah, didn't notice you had listed the humidity numbers. Ya, those are high for winter, but if you don't have a humidifier, you can't turn it down. I wouldn't recommend a dehumidifier, those things don't seem to do much other than creating buckets of water.

Air circulation is the key.

[Boot]

I have a colleague who had a similar problem several years ago. In her case, the windows were just plain bad, causing them to rot. She had two options: replace them entirely or have the dead wood scraped out and epoxied. She chose the latter, and regretted it. The project dragged on and on, and in the end she had several windows replaced anyway.

Your situation sounds sounds like it's for a very different reason, but you might check the level of damage the frames have sustained. If it is extensive, and you have to pay for a fix anyway, you might want to just choose the full replacement rather than screw around with half fixes.

I say half fixes because your humidity isn't really much above normal, so all an HRV is doing to do is lower the humidity in the home... which might make it drier than you prefer and may not solve the problem anyway.

Whatever course you choose, good luck!

Boot.

[Just G]

You can enquire about getting an air brick/vent installed in the rooms with the condensation, these can be placed in close proximity to the windows at just below ceiling height and should hopefully alleviate most of the problems, if you already have them, check that there is no blockage that is preventing air coming through them.

[P8riot]

I am leaning toward the windows too except I am just not very experienced with northern climates. I will forward your description to two of our lead Mechanical/HVAC engineers and see what they say.

[DigitalAssassin]

Originally Posted by P8riot

I am leaning toward the windows too except I am just not very experienced with northern climates. I will forward your description to two of our lead Mechanical/HVAC engineers and see what they say.

Thanks P8triot, appreciate it!

[P8riot]

OK.. here is what Jerry says (he's a Mech. P.E. and does HVAC specification, old skool). He has some more questions -

What kind of heat you use.. specifically baseboard hot water or warm air?
He agrees the humidity is too high and wants to know if there is a humidifier in-use?
Do you do a lot of cooking in your house? (are you were Italian by chance / cook a lot of italian?)
Frequent hot showers?
What has been the outdoor humidity in your area?

He thinks the HRC will work ok for you only if the outdoor humidity is very low. He explained why but it was lengthy.

He also suggested 'storm windows' be added onto your existing windows.. it is what he did when they had the same problem when they lived in NYC. He also repeated that the humidity is high and if temps on-glass get below 30, you would definitely see a lot of condensation because of the relative dew point one would expect.

That is professional opinion #1.. there is still K.C. to respond.. and yes, in-fact, he lived in Kansas City. I could ask Lindsay too but he is a young P.E. and lived in FL all his life too... hence less experience

[DigitalAssassin]

1. Warm air. We have a central heater, just replaced last winter (2004)
2. No. In fact, we run a de-humidifer. It's a stand-alone rolling unit.
3. Not generally.
4. Nope, just 3 showers in the morning. The little guy always takes a bath at night.
5. I'll need to look up the average humidity around the Kansas City area. I'll let you know.

Based upon what you said I'm learning further toward windows.

[icky]

Originally Posted by DigitalAssassin

Based upon what you said I'm learning further toward windows.

Stop leaning!

I can't let you replace your windows after the number of times I have heard advice like what is found at these links:
http://www.burke-sons.com/faq/
http://www.thermalwindowsdfw.com/Con...n%20Facts.html

These guys would surely prefer to sell you new windows if that were the real solution to the problem. Open your windows, run your washroom vents, get that air circulating! You want moisture out and dry air in.

Don't waste your money on new windows over this problem.

[P8riot]

Ya know that 'storm windows' aren't new windows persae.. They are a supplimental window barrier designed to make an additional insulating layer of air.

I don't think I mentioned.. although I am sure Icky was refering to the other guys you've spoken to.. my company doesn't sell anything or represent any particular products.

Edit:
Wait a minute - I was driving in and thinking.. "Wait a minute, Icky's in Ontario - He knows what storm windows are.." LOL.. storm windows are a novel concept to me.. but then we live with Hurricane shields and shutters.

But back to the humidity thing.. our interior averages in the 40 - 50% range with only basic HVAC to control it and we live less than a linear mile from the Gulf of Mexico.

[P8riot]

Welp, thats all I've got for ya DA. KC is out of town now for awhile so I may not hear from him on this. Jerry also added that an HRV would work well if you average outside humidity were 11-19% based on the indoor humidity readings you stated.

He also thought the dehumidifier could be too small, but that it wasn't a great solution overall if it wasn't attached in with the HVAC.

[DigitalAssassin]

Thanks P8triot!

[icky]

Well...

I was referring to the guys in the links. They are window manufacturers, so I consider it meaningful that they would clearly state that you don't need new windows. On the other hand, they are also reassuring people who just bought their windows that there is nothing wrong with them, which is likely a huge hassle for them.

I'm not sure what storm windows are. I suppose in warmer climates maybe you install single-pane windows, but where I live you don't install anything other than insulating windows with 2 panes of glass. Maybe older houses would have storm windows.