Anyone ever hear of a window, or unit of insulated glass, as having different winter and summer U values?
This wasn't on an NFRC sticker. It was on a glass manufacturer's spec sheet.
They listed it like this:
Winter - Air / Argon 0.35 / 0.31
Summer - Air / Argon 0.32 / 0.28
Our program requires a U value of 0.30 to receive an incentive rebate. So obviously, homeowners and contractors want to average the summer and winter Argon fill U values to come up with an average of 0.295 and call it good.
I think it is just a piece of insulated glass that they want to have installed/retrofitted into their existing wood windows, and get an incentive for that.