First things first, the maximum insulation value of a double pane window is R-3. If the window is extremely high quality it might possibly have an insulation value of R-4. In the end the difference is minimal. So now you know replacing your windows is not to going add any substantial insulation value to your home. It now becomes important to understand why else replacing your windows to cut your heating bill will not give you the result you are looking for. First you need to understand the movement of air throughout your home. The reason it feels like air is coming into your home through your windows has to do with convective loops. Your house has to always have a certain amount of air in it at all times, that is obvious. But what effects it has on your home are not as obvious. If your home is not properly air sealed and insulated, the air you are paying to heat is going to leave your home. Warm air rises so the air you paid to heat, to keep you warm will leave out of your roof. This creates the stack effect in your home. As the air you paid to heat leaves the house, new air needs to come in and replace it. Now cold air from outside will start to come in through your box beams, walls, and windows/window joints. You will then pay to heat this cold air as it leaves your home out of your roof creating a never ending cycle. So yes, your windows are leaking, but they are leaking because your home is leaking air and new air needs to come in to replace it. If you get new windows and the installer does a good job installing them and air sealing around his work, you might feel that the windows are not as drafty as before. However the improvement to your home is minimal, when it comes to energy efficiency. Even though you replaced your windows that does not stop air from escaping your home. As a result you still have home that leaks air and is not energy efficent. Even worse, the work you just paid for is not giving you the return you expected. The only way to stop this problem is to properly air seal and insulating your home. If you properly insulate and air seal your home the stack effect is minimized substancially. As a result of this your windows will not be leaky anymore. How would you like to see all the places where your home is leaking air? Want find out how we can make your home even more energy efficient? Give Dr. Energy Saver of the Hudson Valley a call. (845)-361-1150
We will be happy to help you with all of your energy efficency needs.