10 Best Pool Heaters 2025 in the United States

The Hayward W3H400FDN Universal H-Series 400,000 BTU Natural Gas Pool and Spa Heater is a robust option for heating in-ground pools and spas. With a significant heating capacity of 400,000 BTU, it is well-suited for larger pools and spas, providing efficient and fast heating. The heater features a durable cupro-nickel heat exchanger that offers excellent protection against corrosion, which is essential for maintaining longevity and reliability, especially in areas with unbalanced water chemistry.

Its industry-leading hydraulic design is notable for reducing the circulation pump run time, leading to major energy savings and improved efficiency. Additionally, low NOx emissions ensure it meets air quality standards, making it an environmentally friendly choice. The heater's front-panel-only access and intuitive control pad design simplify operation, servicing, and maintenance, which is a plus for ease of use.

It is essential to consider that natural gas heaters can have higher operational costs due to fuel expenses compared to electric or solar options. The initial installation may also require professional help, adding to the cost. Weighing 195 pounds and measuring 39.6 x 32.8 x 30.6 inches, it requires adequate space and planning for installation. This heater is ideal for users needing a powerful, efficient, and reliable solution for heating large pools and spas, with the trade-off being higher operational costs and potentially higher initial setup complexity.

The Hayward W3H150FDN Universal H-Series is a solid choice for those looking to heat their in-ground pools and spas efficiently. With a heating capacity of 150,000 BTU, it provides ample warmth, allowing for comfortable swimming year-round. One of its standout features is the durable cupro nickel heat exchanger, which enhances longevity and protects against corrosion due to unbalanced water chemistry—something pool owners often face. This durability can save you money in the long run by reducing the need for replacements.

Energy efficiency is another strong point, thanks to an industry-leading hydraulic design that minimizes the time your circulation pump needs to run. This means you'll likely notice lower energy bills, which is a significant advantage for budget-conscious users. Additionally, the low NOx emissions are great for those who are environmentally conscious, as it meets air quality standards in low-NOx areas, ensuring minimal environmental impact.

The Hayward W3H150FDN Universal H-Series is best suited for pool owners who prioritize performance, durability, and environmental impact while being prepared for potential installation costs. Its energy-saving features also make it appealing for those looking to reduce operating expenses over time.

The Raypak 206,000 BTU Natural Gas Pool Heater is a reliable choice for those needing efficient and versatile pool heating. One of its standout features is its ability to withstand various weather conditions, making it suitable for different climates. Its heating capacity of 206,000 BTU ensures it can handle a good-sized pool, providing consistent warmth when needed.

The heater has an intermittent spark ignition system, which enhances safety by only activating the pilot when there's a demand for heat. This model also uses space-age materials to avoid retaining residual heat, reducing the need for additional cooling components and simplifying installation. The product is relatively compact, with dimensions of 40 x 28 x 20 inches, and weighs 187 pounds. This small footprint is advantageous for those with limited space.

The heater is designed for high efficiency, which should help keep operational costs down. However, it remains important to consider the ongoing costs of natural gas and maintenance. This heater is not discontinued, ensuring ongoing support and availability of parts. The Raypak 206,000 BTU Pool Heater ranks as a solid mid-tier option at #34 in Swimming Pool Heaters on the market. Potential buyers should factor in the initial investment against its operational cost-efficiency and robust performance in various climates when making their decision.