Cold northern climate.
Although we havent yet turned on our heat (probably today), as the weather
cools we're waking to find the interior of our windows are really wet with
condensation. They're partly fixed pane and partly sliders. A fairly cheaply
built 20 year old house. Placing pastic over the outside is ugly and hides
the exterior. Would caulking the exterior where the glass meets the frame do
it - although this looks pretty tight & I dont see openings. What about
pulling the interior casing off and squirting expandable foam in there? What
is the source? We cant afford to replace them so what can we do?
Given the age and "fairly cheaply built", I'd not expect much in the
way of r-value from the windows. Storms would help.
You can also find insulated, sealing curtains to close off the window
from the inside.
What is the relative humidity inside? Temperatures?
Consider "chimney effect" to be important, too, but not so much so for
your immediate problem. Meaning unwanted air leaks near min and max
elevation of house, which could be transporting relatively warm humid
air (low density) OUT the upstairs leaks. You won't sense cold air
coming in there.
An infrared survey could really help find the facts.
First I suggest that they will likely dry out when you turn on the heat.
Heating will start drying out the inside of your home, it may take a while.
Your calking will not help, although if it were leaking air it would
make the room more comfortable and less expensive to heat.
Pulling off the casing and adding insulation will make the room more
comfortable and reduce heating bills, but not reduce condensation.
You may want to start checking for sources of moisture inside the home.
Do you have an un-vented or improperly vented dryer? Do you have vents in
the bathrooms or at least open the windows after a shower? Any source of
moisture inside the home will increase the problem.
It would be best to get a humidistat and see what the humidity is inside
your home. 40-60 is nice, but you may need to drop to something like 30 to
reduce the condensation without reducing your comfort in your home.
The problem is the inside of the glass is below the dew point of the air
inside the home. You need to warm the glass or reduce the moisture inside
the home. You can warm the glass with thermo pane glass or storm windows
Thanks for this info.
I will check the bathroom and dryer vents. Although i notice these wet
window interiors early in the morning before anyone has shwered or switched
on a dryer.
'>leaking air it would make the room more comfortable and less expensive to
Can you suggest an efficient way to check for leaking air without taking
off all the window casings, or an expensive procedure like thermal/infra red
photography? Holding my hand around the windows doesnt do it.
The fixed pane portions of the windows are double-glazed - is this what you
refer to as 'thermo pane' ?
It is the morning when you are most likely to see it since the windows
will be the coldest.
Cigarette smoke on a windy day should do it.
If they are two panes sealed into a single unit. If the moisture is
forming between the two panes (inside the window) then the seal is bad and
the window will need to be replaced to correct the problem.
All good advice, but if the OP heats with natural gas, that's one of
the major sources of moisture inside the home. Another major source
are the home's occupants - bodies give off a lot of water vapor in
respiration. Then there's cooking, showers, and houseplants. So,
realistically, even if you locate and deal with other moisture sources
in the home, you still have a considerable amount of moisture being
generated on an ongoing basis.
Which may turn out to be either be unachievable or uncomfortable.
And even then, there'll be condensation issues when there's a
substantial temperature differential between the outside and inside.
Considering the R-value of even insulated glass is so far below that
of surrounding walls, of course windows will get colder first, and
moisture will condense on them first. It's one of the reasons why
forced-air furnace ducts are typically located in outside walls near
the windows, so the warm air helps warm the window.
Turning up the thermostat, since warmer air holds more moisture, helps
too, but of course most of us won't want to spend that kind of money
this winter. Applying the interior window film can help, too - when
it's moderately cold, the additional R-value will reduce the
condensation quite a bit, and in very cold weather it'll condense on
the plastic film, instead of on the panes and wood frame.
Another option is having a heat recovery ventilator installed. It will
exchange moist interior air for dryer exterior air while recapturing
most of the warmth of the indoor air. They're a bit spendy to install
but make homes considerably more comfortable in the winter months.
Not when properly vented. If a gas furnace is a major source of
moisture then he a much larger problem than wet windows. He also noted he
had not started using heat yet.
Certainly can. However you would want to take a look at some of the
more common sources.
Most people are OK at 30%, but it is there that most people start having
problems. I agree that 30 is the low end of the comfort range and some
people will be more comfortable higher. I try to keep mine at 35-40
depending on the outside temperature. My humidifier monitors the outside
temp and adjust accordingly. It does a good job.
It does have an effect, but in reality it is really due to raising the
temperature of the glass.
This could help in some climates and some homes, but I suspect that the
OP's home is not tight enough to benefit. Once the heating season kicks in
I would guess his humidity is going to drop below 30% anyway. OP note: when
it gets that cold the glass will be that much colder so it will still cause
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