There are a lot of different variables in your electrical bill. However, as long as all your openings have been replaced including your patio doors and all exterior doors are either replaced or have been properly weather stripped, you will notice a difference in your bill. You need to protect all areas of your home from the outside source of hot or cold. It also depends on the insulation in your walls. If you have very drafting windows, put in energy efficient windows, and you will notice a difference. However, if you have no insulation in your ceiling and your walls, energy efficient windows are not going to help that much. Your windows are like 7-10% of your exterior walls. So energy efficiency should start with insulation. Every little step you make towards energy efficiency will help. They all have to go together. They all have to coincide. However, with energy efficient windows installed, you can save between 30 and 40 % on your fuel bill depending on your energy efficiency. We even have one specific product that can save you 49%. If you upgrade your windows by using the high performance glass and insulate your walls you can save a lot. A window salesman should be able to show you a way to virtually pay for your windows in about six years.
