Heat pumps run on electricity and emit absolutely no exhausts that pollute the air! They are Low NOx by definition. They work by extracting heat from the air and transferring it into the pool water. Since the air is always warm when the pool is in use, it is the perfect and most efficient use for a heat pump. Heat pumps are so efficient at transferring this heat that they operate at a lower cost than natural gas. Heat Pumps are ideal for areas that have a hot climate like Arizona and Florida.
Some heat pumps are also equipped with a chiller that can help cool a pool. This may sound funny to those of you in cooler parts of the country but believe me it is not fun to go into a 90 degree pool when it is 100 degrees outside.