While heat pumps are super-efficient at maintaining pool temperatures, they tend to have a long lead time that is required to bring the water to a comfortable temperature, and they don't perform well in cold climates.
Because gas heaters heat the pool faster, they can be turned off to save energy when the pool's not in use. When it's pool time again, the gas heater can quickly bring the water up to temperature.
Propane and natural gas heaters are speedier because they have a much higher output than heat pumps — 400,000 Btus is a traditional residential-size propane or gas heater, while the biggest electric heaters are just over 100,000 Btus. That means it takes roughly four times as long to heat the water with electric.
Hybrid pool heaters offer an option that combines the rapid heat rise available with propane or natural gas along with the temperature maintenance efficiency of a heat pump.
As more and more customers become energy aware, the availability of high-efficiency products will greatly increase allowing homeowner to enjoy their pool without seeing their heating dollars spiraling down the pool drain.