Simply replacing your windows and doors with ENERGY STAR can reduce energy bills up to 12%! In winter the glass surface will be warmer because Low-E reduces the amount of warm air escaping. You will notice reduced condensation, fewer drafts, lower heating costs and better overall comfort in your home. In the summer, cool air inside your home is retained as the Low-E coating reflects re-radiated heat from outside, keeping the air cool on the inside.