Great idea! A pool cover is a great addition to work side by side with your pool heater. Not only will the cover keep your pool clean, if you cover the pool when you are not using it, but the heat that you have pumped in will also have a much more difficult time evaporating. Overall, a pool cover will help to lower your electricity bill because you will have fewer degrees to conquer and as such, you will also not need to run the heater as often nor for as long.