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<DIV> </DIV>
<DIV>Corwyn writes:</DIV>
<DIV>The other way<EM> (to avoid sweating on windows)</EM> is to raise the
temperature of the glass. Traditionally </DIV>
<DIV>this was done by putting the central heating output right under the </DIV>
<DIV>windows so that hot air washed over the surface warming it up. Now,
the </DIV>
<DIV>solution is generally to increase the insulation value of the windows.
</DIV>
<DIV>The interior storm windows are a cheap way to do this, adding about R-2
</DIV>
<DIV>to a window for about $1.50 per square foot (if you make them yourself),
</DIV>
<DIV>I make them for around $4.00 per square foot. Raising the temperature
</DIV>
<DIV>of the glass will also increase comfort levels (even at the same air </DIV>
<DIV>temperature.</DIV>
<DIV><FONT size=4></FONT> </DIV>
<DIV><FONT size=4>Corwyn</FONT></DIV>
<DIV><FONT size=4></FONT> </DIV>
<DIV><FONT size=4>What kind of glazing do you use. </FONT></DIV>
<DIV><FONT size=4></FONT> </DIV>
<DIV><FONT size=4>I am interested in using inexpensive storm windows as you
describe to improve the performance of common standard and existing
windows. If frame can be light and narrow, the visual impact would be
minimized. I see the design task as making the stops to receive the storm
sash. </FONT></DIV>
<DIV><FONT size=4></FONT> </DIV>
<DIV><FONT size=4>Eli </FONT> </DIV>
<DIV> </DIV>
<DIV> </DIV>
<DIV> </DIV>
<DIV>-----Original Message----- </DIV>
<DIV>From: Corwyn </DIV>
<DIV>Sent: Sunday, October 28, 2012 6:24 PM </DIV>
<DIV>To: Green Building </DIV>
<DIV>Subject: Re: [Greenbuilding] Airtight windows </DIV>
<DIV> </DIV>
<DIV>On 10/28/2012 1:20 PM, Sacie Lambertson wrote:</DIV>
<DIV>Our windows are starting to condensate at the base on the</DIV>
<DIV>> inside. Many of you have suggested this is the penalty of
winter.</DIV>
<DIV>> Isn't there anything I can do about it?</DIV>
<DIV> </DIV>
<DIV>See my previous suggestion for interior storm windows.</DIV>
<DIV> </DIV>
<DIV>Here's the basics of when you will get condensation. When the
dewpoint </DIV>
<DIV>temperature of the inside air is a the same as (or greater than) the </DIV>
<DIV>temperature of the inside surface of the windows (or anything else in
</DIV>
<DIV>your house), that surface will condense water. So in order to avoid
</DIV>
<DIV>condensation you need to either lower the dewpoint of the air inside, by
</DIV>
<DIV>reducing the humidity, or increase the temperature of the inside surface
</DIV>
<DIV>of the windows.</DIV>
<DIV> </DIV>
<DIV>Whether the humidity is too high is a matter of perspective and some </DIV>
<DIV>controversy. Get a humidity gauge and measure what yours is.
Generally </DIV>
<DIV>somewhere in the 40% - 60% range is recommended, but balance is between
</DIV>
<DIV>being too dry (and the dry throat and colds that that produces) and </DIV>
<DIV>being too wet and the mold and mildew (and the allergies that </DIV>
<DIV>aggravates), so decide for yourself. That said, lowering the humidity
</DIV>
<DIV>will reduce the condensation (and vice versa). One of the things we
</DIV>
<DIV>generally see is that as people increase the air tightness of their </DIV>
<DIV>house they need to go from worrying about too low humidity to worrying
</DIV>
<DIV>about too high humidity. At that point, you are probably in the place
</DIV>
<DIV>where you will need to have supplemental ventilation (for fresh air </DIV>
<DIV>reasons), and an HRV will take care of the humidity issue.</DIV>
<DIV> </DIV>
<DIV>The other way is to raise the temperature of the glass. Traditionally
</DIV>
<DIV>this was done by putting the central heating output right under the </DIV>
<DIV>windows so that hot air washed over the surface warming it up. Now,
the </DIV>
<DIV>solution is generally to increase the insulation value of the windows.
</DIV>
<DIV>The interior storm windows are a cheap way to do this, adding about R-2
</DIV>
<DIV>to a window for about $1.50 per square foot (if you make them yourself),
</DIV>
<DIV>I make them for around $4.00 per square foot. Raising the temperature
</DIV>
<DIV>of the glass will also increase comfort levels (even at the same air </DIV>
<DIV>temperature.</DIV>
<DIV> </DIV>
<DIV>Thank You Kindly,</DIV>
<DIV> </DIV>
<DIV>Corwyn</DIV>
<DIV> </DIV>
<DIV> </DIV>
<DIV>-- </DIV>
<DIV>Topher Belknap</DIV>
<DIV>Green Fret Consulting</DIV>
<DIV>Kermit didn't know the half of it...</DIV>
<DIV>http://www.greenfret.com/</DIV>
<DIV>topher@greenfret.com</DIV>
<DIV>(207) 882-7652</DIV>
<DIV> </DIV>
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