Use the optimal temperature settings: A sufficient temperature for spas is 102° F or lower. Higher temperature water can be a safety hazard and cost you a lot more money to maintain that temperature. Check on the accuracy of your pool or spa thermostat. An inaccurate thermostat can increase consumption needlessly.

Do not over-filter: Filtering is a major cost of owning a pool or spa. The average spa requires a minimum of one hour of filtering a day; just enough to maintain water clarity. An average swimming pool often requires approximately 4 to 5 hours of filtering each day in the summer.
Generally, one complete water exchange every 24 hours will provide adequate filtering. If you use a pool maintenance service, ask about reducing the hours of filtration.

Turn off those bubbles: Bubbles may be soothing, but they cool down the water, making the heater run longer to keep the water warm.

Invest in a pool or spa cover: You can save as much as 90% of your summer pool heating costs by using a solar cover. Not only does it help minimize nighttime heat loss (up to 5° F), but it will also prevent chemical loss and water evaporation (hundreds of gallons per month). When shopping for a cover, keep these features in mind: durability, price, warranty, transparency of material, insulation values, and safety.

Protect your pool or spa: Wind has the same effect on your pool or spa as blowing on hot soup. It will cool it off and increase evaporation. Well-trimmed hedges, trees and shrubs, gazebos, and fencing can all provide a nice windbreak.

Consider a timer: A timer gives you day-to-day, automatic control of your filter and heater which will reduce your operating costs.

Go with efficiency: When you replace your filter pump motor consider purchasing an energy efficient model.

Go Solar: Solar pool heating systems are especially effective during the summer months and can back up a regular pool heater in the spring and fall. A solar pool heating system can be a significant investment, so make sure the savings have a payback period of less than or equal to the useful life of the equipment.