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Old 04-26-11, 05:10 PM   #13
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Originally Posted by S-F View Post
In order to get to passivhaus levels you will need 16" - 18" walls (assuming you use cellulose) with no thermal bridging at all. I doubt you will find exactly what you want already set up for you but it wouldn't be too hard to adapt something to meet passive standards.
With some spray foam insulations claiming twice the stabilized R-value of cellulose, it might be doable with 8-9" walls with no thermal bridging, e.g. with steel studs. I wonder, would the increased cost of spray foam insulation be made up for by the savings in lumber, framing labor, window and door trim, and per-square-foot taxes?

Vacuum insulated triple glazing and 18" walls would be nice, but I view them as very expensive toys. I'm inclined to go with a very efficient, 2x6-framed, well sealed house with ventilation heat recovery and good, south-facing double-pane windows. Who knows; it might be passive nine months out of the year, and pretty close in August, January, and February.
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