An increase in your gas or electric bill could be another indication that you need to replace your home’s insulation. There are, of course, a number of things that could cause your bill to increase, so it’s important to control for other factors. You may, for example, be dealing with an inefficient furnace or air conditioner. It could also be that the utility increased your rates. Once you’ve taken other possible reasons for the increase into account, you could benefit from an energy audit.