EcoRenovator - View Single Post - U-value of double pane glass with failed seal

lucerne96 · 05-13-12, 08:08 PM

May I suggest you think of windows two ways. The U-value of the assembly and the air tightness of the window. Look for a modeling program which accounts for air tightness values of windows & doors. Generally, it is a function of gaskets; but also installation. I look for windows with .03 ACH or better, but understand it is part of an overall system. You can substitute less efficient windows & make up for it somewhere else in the design.

I also try to install windows so that the frame is buried IN THE INSULATION ENVELOPE of the building. To do this, you must properly design the rough opening; also design it to minimize thermal bridging.

I could include pix, but can't figure out how to upload. They are not on-line.

PS. install the shades ON THE EXTERIOR of the windows. Once the sunlight (heat) has crossed the energy envelope (window) it's too late!

05-13-12, 08:08 PM	#2
lucerne96 Helper EcoRenovator Join Date: May 2012 Location: house Posts: 50 Thanks: 3 Thanked 5 Times in 3 Posts	May I suggest you think of windows two ways. The U-value of the assembly and the air tightness of the window. Look for a modeling program which accounts for air tightness values of windows & doors. Generally, it is a function of gaskets; but also installation. I look for windows with .03 ACH or better, but understand it is part of an overall system. You can substitute less efficient windows & make up for it somewhere else in the design. I also try to install windows so that the frame is buried IN THE INSULATION ENVELOPE of the building. To do this, you must properly design the rough opening; also design it to minimize thermal bridging. I could include pix, but can't figure out how to upload. They are not on-line. PS. install the shades ON THE EXTERIOR of the windows. Once the sunlight (heat) has crossed the energy envelope (window) it's too late!