Determining the best heating system for your luxury hot tub or custom swimming pool really depends on the location, size, and how often you use your pool. Here are some options that can help narrow down your decision.
Gas Heaters use natural gas or propane and can heat a large volume of water relatively fast making them great for large pools and those not used on a daily basis. Gas heaters can also maintain a set temperature which is good if you live in colder climates. They are more expensive to operate than any other system but costs can be reduced by using pool covers or a secondary heating system once the desired temperature is reached.
Electric Heaters transfer heat from the outdoor air to the the pool water via a heat exchanger. These types of heaters work best in mild climates where the margin between the air temperature and desired water temperature is small and the outside temperature remains above 50 degrees. Electric heaters take a bit longer to heat the water and must run continuously to maintain an even flow of warm water. They are most cost effective for frequently used pools than gas heaters.
Solar Heaters consist of large panels that are installed on the roof of the pool house, home, or other building structure. Open loop solar heating systems should be used in warm climate regions that do not have freezing temperatures. Close Loop systems can reach higher temperatures than direct systems making them a better fit for colder climates.
Geothermal/Ground Source Heat Pumps transfer heat from the ground to the water in your pool via antifreeze filled pipes that are buried in the ground. Unlike air source heat pumps, ground source heat pumps are unaffected by colder temperatures during the winter months so they can be used year round.