9 Best Pool Gas Heaters 2025 in the United States

The Hayward W3H400FDN is a powerful gas pool heater, boasting a robust 400,000 BTU output which makes it suitable for large in-ground pools and spas. One of its standout features is the durable cupro nickel heat exchanger, designed to resist corrosion and ensure longevity, which is particularly beneficial for pools with fluctuating water chemistry. Its energy-efficient hydraulic design is a plus, as it minimizes the run time required by your circulation pump, potentially leading to lower energy costs over time.

Control-wise, the heater offers a user-friendly front-panel access and an intuitive control pad, making it easy to operate and maintain. This aspect can be particularly advantageous for pool owners who may not be very tech-savvy. Additionally, the unit adheres to low NOx emissions standards, making it an environmentally friendly choice in areas where air quality is a concern.

There are some considerations to keep in mind. Weighing in at 195 pounds and measuring nearly 40 inches in length, this heater may require significant space for installation and might be cumbersome to handle without proper equipment. If you have a larger in-ground pool or spa and prioritize efficiency and durability, the Hayward W3H400FDN is a strong contender in the pool gas heater market, provided you have the space for setup and installation.

The Raypak 009218 PR336AENC49 is a robust natural gas pool heater with a powerful 336,000 BTU output, making it an excellent choice for quickly heating large pools. Its high BTU rating means it can efficiently handle extensive pools, providing a comfortable swimming environment even in cooler weather. The heater uses natural gas, which is generally more cost-effective and readily available for most users. Its Integral Fin Copper Exchanger Tube enhances heat transfer efficiency, while the corrosion-free polymer headers contribute to its durability, making it a long-lasting investment for pool owners.

The backlit LCD controls and self-diagnostic microprocessor-controlled ignition add to its user-friendliness, offering easy and precise temperature control and monitoring. However, the heater is quite bulky, weighing 230 pounds, which might require professional installation and sufficient space for setup.

This pool heater is a great pick for those needing reliable, high-capacity heating for their pools, offering both efficiency and advanced control features.

The Hayward W3H150FDN Universal H-Series 150,000 BTU Natural Gas Pool and Spa Heater is designed to deliver reliable and efficient heating for in-ground pools and spas. One of its key strengths is the 150,000 BTU rating, which is suitable for medium-sized pools, allowing for quick and effective heating. The efficiency is enhanced by the industry-leading hydraulic design that reduces circulation pump run time, resulting in energy savings.

Another strength is the durable cupro nickel heat exchanger, which offers excellent protection against corrosion, making it a good choice for those with potentially unbalanced water chemistry. This feature contributes to the heater's longevity and reliability. The heater uses natural gas, making it a cost-effective option for those with access to this type of fuel. It also meets low NOx emissions standards, ensuring it has a low environmental impact, which is beneficial for eco-conscious users.

The control features are user-friendly, with front-panel-only access and an intuitive control pad that simplifies operation, service, and maintenance. The Hayward W3H150FDN is a solid option for medium-sized pool and spa owners looking for efficient, durable, and environmentally friendly heating solutions.