10 Best Gas Pool Heaters 2025 in the United States

The Hayward W3H400FDN Universal H-Series gas pool heater is designed for in-ground pools and spas, boasting a strong BTU output of 400,000, making it suitable for larger pools that require quick heating. One of its main strengths is the durable cupro nickel heat exchanger, which is resistant to corrosion, helping it last longer even in challenging water conditions. Additionally, its efficient hydraulic design reduces the need for long circulation pump run times, saving you money on energy bills.

Operating the heater is made easy with a front-panel access and an intuitive control pad, which is perfect for those not familiar with complex setups. Plus, it meets low NOx emission standards, contributing positively to the environment, which is an important feature for many users today.

However, the heater is quite heavy at 195 pounds, which could complicate installation if you’re not prepared. Lastly, be mindful of the size (39.6 x 32.8 x 30.6 inches) as it may require a significant amount of space. If you are looking for a reliable and efficient heater for a larger in-ground pool or spa, the Hayward W3H400FDN presents a solid option, but keep in mind the installation challenges and the need for adequate space.

The Raypak 266,000 BTU Digital Electronic Ignition Natural Gas Pool Heater is a robust option for pool and spa owners looking for a reliable heating solution. With a substantial BTU output of 266,000, it effectively warms up large pools or spas quickly, making it suitable for both casual and frequent users. Its efficiency is enhanced by the intermittent spark ignition pilot safety controls, ensuring that the pilot light only activates when heat is needed, which can help save on gas costs.

One of the standout features is its construction from advanced materials that prevent the retention of residual heat. This design not only allows for straightforward installation without expensive metal heat sinks but also aids in energy efficiency. Additionally, the programmable thermostat adds convenience, enabling users to set heating schedules tailored to their needs.

The Raypak heater might be on the heavier side, weighing 210 pounds, which could complicate installation for some users. Furthermore, while it's designed for outdoor usage, ensuring durability against various weather elements is crucial for long-term performance. If you’re looking for a powerful and efficient pool heater that’s easy to manage, the Raypak 266,000 BTU model could be a great fit. However, consider your installation requirements and be aware of the need for regular maintenance to ensure it performs optimally over the years.

The Hayward W3H135FDN H-Series Pool/Spa Heater is a reliable choice for those looking to efficiently heat their pool or spa. With a BTU output of 135,000, it is suitable for small to medium-sized pools and spas, providing ample heating power. Its use of natural gas makes it a cost-effective option for long-term use.

The heater features a durable cupro nickel heat exchanger, known for its resilience against corrosion, which extends the product's lifespan and reliability. The industry's leading hydraulic performance ensures fast heating, allowing you to enjoy your pool or spa sooner after turning the heater on. The intuitive electronic panel makes it easy to operate, even for those not tech-savvy. Additionally, the low NOx emissions mean it's environmentally friendly and meets clean air quality standards.

On the downside, weighing 100 pounds and with dimensions of 21.5 x 30 x 22.5 inches, it may require professional installation due to its size and weight. The product’s strong build quality and materials suggest good durability, but it's always wise to verify the warranty details with the manufacturer. This heater is ideal for pool owners who prioritize efficiency, ease of use, and environmental considerations.