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 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.

The Hayward W3H135FDN H-Series Pool/Spa Heater is a natural gas model designed to offer a blend of performance and durability. It boasts a BTU output of 135,000, which is suitable for medium-sized pools and spas. One of its key strengths is the durable cupro nickel heat exchanger, which ensures long-term reliability and resistance to corrosion. This makes it a good option for pools with saltwater or high chemical usage.

The heater's efficiency is bolstered by its industry-leading hydraulic performance, enabling faster heating times, which can be a significant advantage during cooler months or for those who want to quickly heat their pool or spa. The intuitive electronic control panel is user-friendly, allowing for straightforward operation without needing technical know-how. Additionally, its low NOx emissions mean it meets clean air standards, making it an environmentally friendlier choice compared to other models.

In terms of size, the dimensions are 21.5 x 30 x 22.5 inches, and it weighs 100 pounds, which means installation should be manageable for most users, although professional installation is recommended. This heater is particularly well-suited for pool owners looking for a durable, efficient, and easy-to-use heating solution that also prioritizes environmental considerations.