Modern windows are measured with an R-value, a U-factor and a Solar Heat Gain Coefficient. 'Huh,' you say. Read on to find how to turn a window into a thermostat.

Your house is chronically too cold. Even in the daytime it is tough to sit in a window seat. Not only is this uncomfortable, but it is driving your electricity bill through the roof.

Find replacement windows that measure up in terms of the U-factor, R-Value and Solar Heat Gain Coefficient. The U-factor of a window is the speed of heat transfer from inside of your home to the outside of your home. The lower the U-factor the better heat stays inside. The R-value of a window is the measurement of resistance to heat flow. The higher the R-value the better your window is at stopping any heat transfer. The Solar Heat Gain Coefficient (SHGC) is the measurement of solar heat gain inside your home. A high SHGC means a lot of solar heat is being absorbed inside the home.