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MN Renovator · 03-28-12, 12:43 PM

Yikes, the best of the best windows are definitely expensive. I've had a little day dream about me walking around the house in December stuffing 2" XPS (R10) into the window cavities with the outside covered in a white or colored bedsheet somehow fashioned make it look like drapes from the outside. Cheaper than windows and complete privacy but no solar heat gain. My energy auditor said that typical double pane energy star windows, even on the south side would lose more heat on a 24 hours than could be gained during the day and that even an R13 wall assembly with less window area is a better bet. I'm curious what R value(actually U value) of window and what level of solar gain is needed to balance this out with the limited sun in northern US or Canada, colder night outdoor temperatures and limited thermal mass to store the gained heat for more passive application.

I'm also curious about high SHGC windows and what you do in the summer until you can grow deciduous shade. I wouldn't mind 'forced/mechanical shade' but when the noon/evening sunny side of your house is facing the street putting shutters, shades, or awnings over the windows would make a house look like the odd one in the neighborhood. I was dedicated to the thought of mounting acrylic with tinted sheet or something over my sunny side windows in the summer but realized that it would be over $200 for just the living room and I wasn't sure how well that would work out but after testing aluminum foil over my port southern side windows in the master bedroom it seemed to cut the heat in that room dramatically with the door shut. 5 degrees lower during the peak sun period from one day to the next with roughly the same cloudless sun and temperatures. Looked unsightly from the outside but I kept them up for two months since I have trees that block the view of those windows from the street but aren't tall enough to block the light coming in. This whole XPS over the windows thing is a thought that is gaining traction, even if it is only a week long trial for the week predicted to be the hottest here. Am I crazy?

03-28-12, 12:43 PM	#34
MN Renovator Less usage=Cheaper bills Join Date: Nov 2010 Location: Minneapolis, MN Posts: 939 Thanks: 41 Thanked 116 Times in 90 Posts	Yikes, the best of the best windows are definitely expensive. I've had a little day dream about me walking around the house in December stuffing 2" XPS (R10) into the window cavities with the outside covered in a white or colored bedsheet somehow fashioned make it look like drapes from the outside. Cheaper than windows and complete privacy but no solar heat gain. My energy auditor said that typical double pane energy star windows, even on the south side would lose more heat on a 24 hours than could be gained during the day and that even an R13 wall assembly with less window area is a better bet. I'm curious what R value(actually U value) of window and what level of solar gain is needed to balance this out with the limited sun in northern US or Canada, colder night outdoor temperatures and limited thermal mass to store the gained heat for more passive application. I'm also curious about high SHGC windows and what you do in the summer until you can grow deciduous shade. I wouldn't mind 'forced/mechanical shade' but when the noon/evening sunny side of your house is facing the street putting shutters, shades, or awnings over the windows would make a house look like the odd one in the neighborhood. I was dedicated to the thought of mounting acrylic with tinted sheet or something over my sunny side windows in the summer but realized that it would be over $200 for just the living room and I wasn't sure how well that would work out but after testing aluminum foil over my port southern side windows in the master bedroom it seemed to cut the heat in that room dramatically with the door shut. 5 degrees lower during the peak sun period from one day to the next with roughly the same cloudless sun and temperatures. Looked unsightly from the outside but I kept them up for two months since I have trees that block the view of those windows from the street but aren't tall enough to block the light coming in. This whole XPS over the windows thing is a thought that is gaining traction, even if it is only a week long trial for the week predicted to be the hottest here. Am I crazy? Last edited by MN Renovator; 03-28-12 at 12:45 PM..