FAQ’s
There is only one reliable way to compare windows and that is by asking for the NFRC rating for each window that you are considering. NFRC labels are independently certified and rate the whole window performance by U-Factor and Solar Heat Gain Coefficient (SHGC). The lower these ratings are the better the window will perform. The priority of U-Factor versus SHGC depends on your climate. You should ignore all the sales hype and choose the best NFRC ratings for your climate at the best cost.