I live in a side by side 1 floor with a basement duplex, with a total of 7 windows. Last summer (2012), 2 West facing windows were replaced, and this summer (2013) 2 North facing windows were replaced.

Now that it's getting cold outside, ever since we've had to close the windows up for the winter, every window has had a lot of condensation on them. All the new windows had about the lower third of the window covered with condensation, that would drip down onto the wood frame and was soaking the wood. The 3 front windows, which are still wood frame windows, about 20 years old, were completely covered with condensation. Some days you couldn't see out the window the whole day without wiping them down.

We've had to run a dehumidifier in the living room, which has helped with the humidity, but should this be necessary? The windows weren't installed by a window company, just purchased and then installed by a jack-of-all-trades handyman.

What should the landlord (my wife's Grandpa) do? Call the installed up because his installation wasn't done correctly? I'm afraid of mold growing on the wood around the windows and us breathing it in.

Thanks for any help I can get.

 

Did you check the humidly level with a real gauge?
Is there a bathroom exhaust fan, and is it being left on a few min. after taking a shower?
Is there an exhaust fan over the stove that blows outside?
Did the installer apply caulking around the stop before installing the window?
Is there caulking around the frame of the window on the inside and out?
If you had the old style windows with weights there about a 4" wide empty hole that needed to be filled with insulation on the sides of the windows letting in cold air. When it hits the warm side of the window it's going to condense the moist air in the house.

 

I haven't checked the humidity with a real gauge.

Last winter I upgraded the bathroom fan from a 30 CFM to 100 CFM fan, and usually run it for 15-20 minutes after a shower. The fan above the stove doesn't vent outside, it's a microwave with a "fake" exhaust fan on top.

I'm not sure if the installed applied caulking around the stop. I don't remember seeing him installing any insulation after he took out the old windows.

 

The fact both the new and the 20 year old windows are having condensation issues is a result of too high relative humidity ( RH ) in your home --- likely 50-60% or higher.

More than likely the replacement windows are more sealed and not allowing air leaking into and out of the house like those old windows they replaced. The air leaking into and out of the home during the winter drys out the house --- lowers the RH. This is why many people find their homes are dryer during the winter. Once the house becomes *tighter* there is less air exchange and the RH increases.


I don't believe the new window installation is the problem. Instead you need to maintain a lower RH inside the home during winter.

 

So just continue using the dehumidifier? Since running it upstairs, the condensation has gone away.

 

That's the bare minimum amount of time -- longer is better.




Whatever it takes. As you see lowering the indoor RH is improving things.

 

A tough one. For the most part I agree with Canuk, making the house tighter will reduce the infiltration of dry cold air which can control excess humidity. But eliminating the leakage from just 4 (of 7) windows would normally not create this extreme change. If it did, the dehumidifier or a heat recovery ventilator can be a partial solution.

But, if there is a moisture issue from a poor installation, then other related problems may go untreated. With more details maybe we can increase the confidence level.

What type of heating, forced hot air, baseboard hot water, other?

Were the new windows "new construction" or "replacement style"? The second one is installed into the existing frame of the old windows and would not typically require removing the trim or siding work.

We will want actual humidity and the room temperature numbers. Temperature changes the RH.

Are the replaced windows protected from some of the rain by an overhang outside?

The other approach is the list Joe posted, controlling the normal sources of moisture. Do you dry cloths inside? Is the cloths dryer vented to outside and not blocked? How many people living there? Do you cook a lot? Pets? Aquariums? Plants?

Bud

 

Just a comment. Typical humidity in the NE of the US should be about 35 to 45%. Any thing lower and you wake up with dry mouth in the morning and sinuses become inflamed. That's why furnace humidifiers are used.
I have older windows that sweat a lot since installing the humidifier. But the comfort is worth all that. Sounds to me you have lots of cold air coming in from some source, either the window or other areas.

 

The heating is forced air, with no heat recovery ventilator.

The windows were replacement style, installed into the existing frames.

The RH is between 50-60 depending on the temperature outside.

The windows do have an overhang about them. The 3 old ones almost never get any rain on them, 2 facing west always get rain on them, and the 2 north windows sometimes get rain.

We use a dryer in the basement, vented outside. Checked and not blocked. There are 2 people living here, 2 pets and 2 20 gallon aquariums in the basement. We've got about 7 plants in the entire house, mostly under 10" high.

 

Changing the windows would probably not increase the humidity. If they did, it would be because your old windows were so leaky that they were ventilating the humid air out of the home, and letting fresh (dry) air in.

Bottom line is you need to lower the humidity. It should be around 30% inside the home if you don't want windows to sweat in the winter time. If you have a humidistat on the furnace, turn it off.

 

Ok, so how do I get the humidity down? There isn't a humidistat on the furnace. Just run a dehumidier upstairs and downstairs all year long?

 

Well, we used to have a member here that encouraged people to open some of the windows a crack to let cold dry air into the house. That seems like a waste of energy, but it does lower humidity, since cold winter air is usually dry air. Running bath fans, adding dehumidifiers are options too. Basements are big sources of humidity. So are clothes dryers, showers, cooking, breathing (why bedroom windows fog over if you close the door at night) and any sort of gas combustion (furnace/water heater / gas ranges) can put some moisture in the air, although they are usually properly vented.

Windows will sweat worse if they are colder than normal. So if, after replacing your windows, you felt more comfortable in the house and either your furnace ran less often or you turned the thermostat down a degree or two, that could also be making your windows a degree or two colder.

Something else that can make windows colder than they should be is if the perimeters are not insulated properly... heat will radiate from the frames making them cold. Insulation around the frames slows this heat loss, making the windows warmer and less prone to condensation. But that doesn't explain why the old windows have more condensation than usual. I doubt that's it.

The thing that's odd is that you say your old windows have more condensation than ever. Sounds odd to me, like there may be another source for the moisture and you just automatically are thinking its the windows. Is there anything else at all that could have changed, or has been improved / repaired on the home?

You say its a duplex. What's to say there isn't something going on next door that is affecting the whole house humidity. What about their bath fans and the amount of showers they are taking? New tenants, or more tenants = more showers? Old tenants preferred baths / new tenants prefer showers? Old tenants took 5 minute showers / new tenants take 20 minute showers? Just a few things to think about that could drastically affect the amount of moisture going into the air. Roof ventilation can affect home humidity too.