10 Best Natural Gas Pool Heaters 2025 in the United States

The Hayward W3H400FDN Universal H-Series 400,000 BTU Natural Gas Pool and Spa Heater stands out for its robust heating performance, making it a great choice for large in-ground pools and spas. With a high BTU output of 400,000, it can efficiently heat large volumes of water quickly, ensuring your pool or spa is ready for use when you are. The heater's efficiency is enhanced by its industry-leading hydraulic design, which reduces circulation pump run time, resulting in significant energy savings.

Additionally, the durable cupro nickel heat exchanger offers excellent protection against corrosion, especially in pools with unbalanced water chemistry, extending the heater's lifespan. Ease of use is ensured by the front-panel-only access and intuitive control pad, simplifying operation and maintenance. Furthermore, its low NOx emissions make it an environmentally friendly option, meeting air quality standards in all low-NOx areas.

However, the heater is quite large and heavy, with dimensions of 39.6 x 32.8 x 30.6 inches and a weight of 195 pounds, which may complicate installation and require professional assistance. Additionally, while it performs well, it may be noisier than some other models, which could be a consideration for those seeking a quieter solution.

The Hayward W3H250FDN is a powerful natural gas pool heater that delivers 250,000 BTUs, making it suitable for in-ground pools and spas needing strong, consistent warmth. Its standout feature is the cupro nickel heat exchanger, which helps resist corrosion and extends the heater’s lifespan, especially if your pool water chemistry isn’t perfectly balanced. This model is designed with energy savings in mind, thanks to an advanced hydraulic system that reduces the time the pool’s circulation pump needs to run.

You’ll find operation and maintenance straightforward with its front-panel access and easy-to-use control pad. It also meets low NOx emissions standards, meaning it’s more environmentally friendly and better for areas with strict air quality rules. The size is fairly standard for this type of heater, weighing 165 pounds and requiring some space for installation, so professional setup might be necessary. At nearly 33 inches in each dimension, it’s not the most compact option available.

If you want a reliable, efficient heater with a focus on durability and lower environmental impact, this model presents a strong option. However, if space constraints or ultra-quiet operation are priorities, you might want to explore other choices.

The Hayward W3H150FDN Universal H-Series Natural Gas Pool Heater is designed for those seeking effective heating for in-ground pools and spas. With a solid BTU output of 150,000, it can heat water quickly, making it suitable for both small and large pools. One of its major strengths is its durable cupro nickel heat exchanger, which protects against corrosion and extends the heater's lifespan, especially in areas with unbalanced water chemistry. This feature is particularly beneficial for pool owners looking for long-term reliability.

Energy efficiency is another highlight, thanks to its advanced hydraulic design that minimizes circulation pump run time, ultimately leading to cost savings on your energy bills. Users will also appreciate the front-panel access and intuitive control pad, which simplify operations and maintenance, making it friendly for all skill levels.

On the downside, the heater is relatively heavy at 150 pounds, which might pose challenges during installation, especially for those who prefer a DIY approach. While the low NOx emissions are great for environmental considerations, some users might find the noise level slightly higher compared to other models. For pool owners who prioritize durability, energy savings, and ease of use, the Hayward W3H150FDN is a strong contender. However, those sensitive to noise or looking for a lighter unit may want to explore alternative options.