I saw a demo of two extruded vinyl casement windows that had 500 watt flood lights illuminating one side of each window. One glass was of type Low E, the other was Type Low E2. There was a fair amount of heat on the opposite side of the E window but the opposite side of the E2 was unbelievably cool. Price was the same for both windows. Is there any reason not to select the E2 window which appears more energy efficient? My concern is that during the Winter months I get a tremendous amount of sun and therefore free heating energy. Would these E2 windows not block all that heat?
Answer:
I would not let the negligible amount of heat recovery nor loss interfere with a decision regarding a product as expensive as windows. As far as the technicalities of 'E' go, I don't know enough about it to permit that to make a difference. Other than people who themselves conduct scientific studies in the field, I really don't think many others do either. Going through certain motions and repeating given sales pitches though, make for good demonstrations and a lot of sales to the uninitiated.
