Q. What advice do you have for replacing windows?
A. Replacement windows are windows designed to fit into the same structure that the old windows come out of.
When considering which type of glass will work best for you, consider the R-value and the U-factor. These are ratings replacement-window manufacturers assign to their windows that tell you how efficient they are.
The R-value of a window indicates how well it insulates. These values go from 0.9 up and a window that insulates fairly well will have a rating of 3 or more.