[header] How to drastically reduce the cost to heat your swimming pool [title] Use a pool cover. [step] Evaporation is the largest source of energy loss for pools. This can easily be prevented by using a pool cover whenever the pool is not in use, which will minimize evaporation. 
It's the most effective way to reduce pool heating costs-it can reduce cost by as much as 50 to 70 percent. There are several pool cover options available on the market, including manual, semi-automatic, and automatic pool covers.