We get moisture on our windows at night when it gets cold. Ice even
builds up on the inside of the windows if it gets below maybe 10 degrees
outside. Our house is 9 years old and is sealed pretty tight. I built
some inside storms for one set of windows and that really helped. I was
just wondering if maybe a ventilation system, like a Venmar might be a
better solution. It is hard to believe we have high humidity in the
house in the winter time when the humidity is so low outside and the
skin dries out so quickly. I have checked the humidity in the house and
don't remember the numbers but it didn't seem very high, like 30% maybe.
So why are the windows icing up? Do I need indoor storms on all my
windows or is there a better solution?
I don't know what the dew point is when inside temp is 30 per cent and temp
70 degrees, but it is not that low - certainly above the temp near the
inside of the window when it is biting cold outside. Therefore, one would
expect some ice and condensation inside, especially with single glazed
windows, or DIY double glazing, which has leaks.. Finding condensation is
common everywhere where you have cold high humidity outside temperatures,
with moderate inside humidity. Gas charged double glazing will increase
insulation slightly from R1 to R2, and may reduce condensation, but outside
of improving inside air circulation, there is little that can be done that
will have dramatic results. Keeping miniblinds or curtains slightly open,
or raised a few inches above the sill is helpful, as it creates a downdraft
along the interior face of the window, which has a defrosting effect.
Remember dew point? When the temp gets low enough,,,, below freezing any
water that is in the air will condense eventually.
Storms inside we had ours outside. Do you have any air movement available?
Fans might help.
ISU 1969 temps went to ~ -25 F. We taped card board on the windows in a 60
degree angle and used the space between the card board and the window as a
refrigerator. We did not have such things in our dorm then..Grab all the
butter pats you could carry so we could have butter on the pop corn later
30 percent humidity is not high, but if you limit air flow
by pulling curtains you will get condensation and ice build
up. I assume you have double pane windows, if you don't you
certainly will get ice build up if you keep a reasonable
temperature inside and you will even with double pane
window. Inside storms are ok, but a better solution is
outside storm windows especially on the north side.
Andy Arhelger wrote:
From my aprilaire humidifier manual:
They recommend decreasing interior R.H. as the outside temperature goes down
by the following table:
outside temp (F) inside humidity
my experience is that these numbers are optimistic and cutting the
humidities in half is not out of the question with cheap windows and cheap
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