U Factor, Visible Transmittance, etc..

[cookkev3]

Is this a good window?

1/2" Air LoE
U Factor - 0.35
Solar Heat Gain Coefficient - 0.34
Visible Transmittance - 0.52

What are the best values for Solar Heat Gain adn Visible Tranmittance. I see that the U factor should be as close to 0.3 as possible.

Kevin

[FenEx]

Cook

Those ratings are not impressive... actually quite poor by available standards. Great numbers would be in the low .20's for a U-factor, low .30's for a VT, and low .20's for a SHGC.

[Windowtech]

if you are living in the south, Solar Heat Gain Coefficient is more important, and if you are living in the north, U-Value becomes more important (and a slightly higher SHGC can actually be beneficial). What is imprtant, is the total annual energy costs associated with a window of a given design. There are computer programs which can calculate this for major cities. One such program is Resfen. Contact LBL in California to learm more. Go to http://windows.lbl.gov/ and click on "software."