House moisture problem

[cosine]

My parents' house seems to have a moisture/condensation problem. Every morning the inside of the windows in the house are covered with water (I assume from condensation), oftentimes reaching halfway up the window or further. If you don't run around and wipe all the water off of the window, it begins to run down window pane into the window sill. It has pretty much ruined every window sill in the house.

My parents have had this problem with the windows every late fall through early spring ever since they built the house about 15 years ago.

Does anyone know what's causing this problem, and what could be done to fix it/prevent it from continuing?

Thanks. 

[K Frame]

There could be a LOT of different causes, from an inadequately sealed basement or crawlspace to the house being too tightly sealed and too poorly ventilated.

One possible fix, at least short term, is a dehumidifier.

[cosine]

There could be a LOT of different causes, from an inadequately sealed basement or crawlspace to the house being too tightly sealed and too poorly ventilated.

One possible fix, at least short term, is a dehumidifier.

They run a dehumidifier. My dad thinks it's a too tightly sealed problem.

[Matthew Carberry]

When heated, humidified air hits cool glass you're going to have condensation.

Are the windows double-paned and insulated?  That can help keep the inside pane not as cool and prone to condensation.

They should look into adding less moisture or increasing their ventilation.

[280plus]

Too much humidity, turn down the humidifier, get a hygrometer at the local cigar store and try to keep it between 40 and 50%. If the windows still fog think about new double pane windows or maybe plastic over them in the winter.

[cosine]

Thanks for the advice.

[Brad Johnson]

What type of heating system do they have, and do they run any kind of supplimental heat?

Also, do they keep a lot of plants in the home?

Brad

[Matthew Carberry]

One other thing to keep in mind.  If they are having condensation problems and actual water damage they are at risk to develop mold problems.

Venting is key, if taking some of the other steps suggested don't help they may want to call in a contractor to look at the problem from an overall pespective.

[HankB]

Sounds like over night, the temperature of the inside surface of the windows is falling below the dewpoint of the air inside the house. There are three obvious solutions:

1. Reduce the indoor humidity with something like a dehumidifier. Since they're doing this already . . .

2. Replace the windows with more energy-efficient designs.

3. Cover the windows on the inside with either insulated shutters or 3M indoor window film.

When I lived in MN I had the same problem, and used the 3M window film . . . this assumes you have something smooth (like woodwork) to tape the window film to. Use the special double-backed tape that the film comes with and you won't damage the woodwork. If you have wrinkles after you apply it, a heat gun (hair dryer) will "shrink" it for a taut surface.

 

[280plus]

I've found in the past, using a humidifier, that if you have cold windows they may fog and suck up all the moisture even though the room humidity is not high enough. USUALLY, its with single pane glass and storm windows, which I suspect is what cosine's situation is. I've even seen the moisture freeze on the inside of the window and accumulate a nice sized lump of ice after a while. In any case plastic sheeting over the inside for the winter is the cheapest and easiest answer. Kind of a PITA though.

hank just beat me... 

[cosine]

They have forced air heating. That's it.

Not many plants in the house, maybe one or two.

They run a dehumidifier, but the humidity level in the house still stays around 40-50% in winter. (Excuse my typo in my second post, they do not run a humidifier, they run a dehumidifier.)

[Brad Johnson]

They have forced air heating. That's it.

Not many plants in the house, maybe one or two.

They run a dehumidifier, but the humidity level in the house still stays around 40-50% in winter. (Excuse my typo in my second post, they do not run a humidifier, they run a dehumidifier.)

50% with a dehumidifier is ... a lot.  By chance does the humidity inside ever exceed the humidity outside? 

Brad

[cosine]

They have forced air heating. That's it.

Not many plants in the house, maybe one or two.

They run a dehumidifier, but the humidity level in the house still stays around 40-50% in winter. (Excuse my typo in my second post, they do not run a humidifier, they run a dehumidifier.)

50% with a dehumidifier is ... a lot.  By chance does the humidity inside ever exceed the humidity outside? 

Brad

On cold, cold day in winter, probably. Maybe the humidity is just a factor of having nine people living in the house.

[Harold Tuttle]

I run an april aire humidifier on my heat pump forced air system.

When my dome skylights drip,
it reminds me to turn back the humidity.

During a really cold week,
my single pane front storm door will ice over,
if the main door is left open.

[Brad Johnson]

On cold, cold day in winter, probably. Maybe the humidity is just a factor of having nine people living in the house.

Need more info...

What we know:
Forced air
Humidity approaching 50% at times, even with a functional dehimidifier

What we need to know:
Fuel source for heating (gas, oil, electric, combo, etc)
Window style (single glazed, double glazed, solar shield, etc)
Storm windows?
Age of home
Foundation style (slab, pier & beam)
Basement?  If so, full or partial, and does it seem damp?
"Average" outside humidity

Just on the surface it seems like your parents' home is getting moisture intrustion from somewhere, but more info is needed to diagnose.

Brad

[cosine]

On cold, cold day in winter, probably. Maybe the humidity is just a factor of having nine people living in the house.

Need more info...

What we know:
Forced air
Humidity approaching 50% at times, even with a functional dehimidifier

What we need to know:
Fuel source for heating (gas, oil, electric, combo, etc)
Window style (single glazed, double glazed, solar shield, etc)
Storm windows?
Age of home
Foundation style (slab, pier & beam)
Basement?  If so, full or partial, and does it seem damp?
"Average" outside humidity

Just on the surface it seems like your parents' home is getting moisture intrustion from somewhere, but more info is needed to diagnose.

Brad

Fuel source: gas
Windows: double pane, casement style
Storm windows: no
Age of home: 15 1/2 years
Foundation: slab (I think)
Basement: full height concrete block basement, not damp
Average outside humidity: I think it fluctuates between 60-80%
House: 2400 sq. feet, two floors

[280plus]

That was a DE-humidifier? Yup, that'll change things. 

Wow, that's very strange. If the house is tight I guess 9 people would put out a enough moisture to fog the windows. Definitely check inside humidity vs outside humidity. What's the outdoor temp when this is happening?  Check the gas furnace flue to make sure it's all in one piece and not spilling flue gas into the house. Is the clothes dryer vented properly? What about moisture from cooking, washing dishes?

Where (what state) is the house?

[cosine]

That was a DE-humidifier? Yup, that'll change things. 

Wow, that's very strange. If the house is tight I guess 9 people would put out a enough moisture to fog the windows. Definitely check inside humidity vs outside humidity. What's the outdoor temp when this is happening?  Check the gas furnace flue to make sure it's all in one piece and not spilling flue gas into the house. Is the clothes dryer vented properly? What about moisture from cooking, washing dishes?

Where (what state) is the house?

Southeastern WI. Easternmost edge of New Berlin. Nine miles west of Milwaukee.

This happens pretty much all winter, when temps are usually below 45* F.

Gas furnace flue is fine. Clothes dryer is vented properly.

With nine people in the house, there is a lot of cleaning that goes on. Dishwasher gets run 2-3 times a day, usually so does the clothes washing machine.

[280plus]

There ya go... Bigger dehumidifier or a second one might do the trick.

[cosine]

There ya go... Bigger dehumidifier or a second one might do the trick.

I just had a thought... maybe a dehumidifier on one of the "living" floors of the house would be needed. Right now the dehumidifier is on all the time, but is relegated to the basement.

[Matthew Carberry]

The water vapor is riding the warm air so putting the de-humidifier up high makes sense.

[Car Knocker]

If they cook on a gas range, that will put a lot of water in the air.

[280plus]

Oh, it's in the basement. 

Yup, it's not going to do much for the living area being down there. Carknocker is right too.

Can't say I've dealt with a whole lot of houses that had too much natural moisture in the winter. Tell everybody to stop breathing. 

A dehumidifier would probably work. It'll drain a lot so I'd get one that you can run to a drain somwhere instead of emptying a bucket all the time. OR maybe kitchen and bath exhaust fans? Start using them if you don't.

Fun fact, the average human body AT REST is good for about 500 BTU per hour X 9 = 4,500 BTUH of FREE HEAT!! 

[HankB]

Nine people in a 2400 square foot home is a crowd . . . and each person is basically a humidifier. Dishwasher use, cooking, bathing . . . all put moisture into the air.

If the basement dehumidifier is sucking lots of moisture out of the air, leave it there - it's WORKING, and you don't want mildew or mold in the basement. I had one in my basement when I lived in Minnesota, but I still needed to put 3M window film over the windows upstairs to keep condensation from forming.

As I wrote, the ONLY reason you get condensation on the windows is because the inside surface of the glass falls below the dewpoint. Further "dehumidification" may not be practical - you'd need a SECOND dehumidifier on the main floor - so insulating the windows is just about your only alternative.