Recently, I opened my curtains to look out on six inches of snow and sub-zero temperatures. I noticed a line of ice along the inside of my window sill and wondered, if ice can get in, how much heat is getting out?

The average American home loses up to 1/3 of its heat through poorly insulated windows and doors, costing American consumers millions of dollars every year. Basic “weatherization” measures that increase household energy efficiency are one of the easiest ways to save money, improve home comfort, and help protect air and water quality.