Contrary to common belief, your "windows & doors" are not the largest contributors to your utility bills. Older, leaky windows & doors can cause drafts and be a part of the problem, but are often expensive solutions. Your Heating & Cooling, as you can see, make up the largest portion of your monthly utility bill. Older, inefficient appliances and older water heaters can also add to those costs. Now that we've debunked myth number 1, lets got to Lesson #2 to understand more about how 20-30% of your utility costs is being wasted.