Author: Joe (---.kc.rr.com)
Very informative discussion here. I went out and looked at the NFRC site myself and compare the Schuco and Gorrel windows. I did the triple pain with Krypton Gas to see how each rated.
Gap Tint U-Factor SHGC VT Conden
Schuco .276 LE .2 .28 .37 72
Gorell .3 LE .19 .23 .36 ?
Gorell also had 3 layers of glazing and Schuco listed 0.
Now maybe I'm wrong but just looking at the glass, you would think Gorell is the better window. It has a wider gap, better U-Factor, Better SHGC, and better VT. Not sure on the condensation on Gorell. I think all the windows listed are comparable, and each has it's own strong points. Most of your energy will be lost through the glass and how well the window seals. Can someone tell me what they are charging per window to install the Schuco? From what I read you can get the others for around $500. Gorell also had the better warranty. If everything I have read about the cost, the gorell seem to be the better window for the money.
U-factor measures how well a product prevents heat from escaping. The rate of heat loss is indicated in terms of the U-factor (U-value) of a window assembly. U-Factor ratings generally fall between 0.20 and 1.20. The insulating value is indicated by the R-value which is the inverse of the U-value. The lower the U-value, the greater a window's resistance to heat flow and the better its insulating value.
Solar Heat Gain Coefficient
Solar Heat Gain Coefficient (SHGC) measures how well a product blocks heat caused by sunlight. The SHGC is the fraction of incident solar radiation admitted through a window, both admitted through a window, both directly transmitted, and absorbed and subsequently released inward. SHGC is expressed as a number between 0 and 1. The lower a window's solar heat gain coefficient, the less solar heat it transmits
Visible Transmittance (VT) measures how much light comes through a product. The visible transmittance is an optical property that indicates the amount of visible light transmitted. VT is expressed as a number between 0 and 1. The higher the VT, the more light is transmitted.
Air Leakage (AL) is indicated by an air leakage rating expressed as the equivalent cubic feet of air passing through a square foot of window area (cfm/sq ft). Heat loss and gain occur by infiltration through cracks in the window assembly. The lower the AL, the less air will pass through cracks in the window assembly.
Condensation Resistance (CR) measures the ability of a product to resist the formation of condensation on the interior surface of that product. The higher the CR rating, the better that product is at resisting condensation formation. While this rating cannot predict condensation, it can provide a credible method of comparing the potential of various products for condensation formation. CR is expressed as a number between 0 and 100