Gas-fired pool heaters remain the most popular system for heating swimming pools. Today, you can find new gas-fired heater models with much higher efficiencies than older models. Still, depending on your climate and pool use, they may not be the most energy-efficient option when compared to heat pump and solar pool heaters.
Heater efficiency indicates the percentage of energy the system can use compared to the energy spent. For example, an 80%-efficient heater uses $80 worth of useful heat for every $100 worth of fuel. herefore, it wastes 20% of the fuel. A five to ten year old gas pool heater may be 70-75% efficient, while a ten to twenty year old heater may be 60-65% efficient. Today's market offers some gas pool heaters with efficiencies as high as 89%-95%. If your current heater is 65% efficient and was replaced with a 95% efficient heater, you would save $300 per year for every $1,000 in annual pool heating costs.