10 Best In Ground Pool Heaters 2025 in the United States

The Hayward W3H250FDN Universal H-Series 250,000 BTU Natural Gas Pool and Spa Heater is a strong contender for anyone looking to heat an in-ground pool or spa. With a heating capacity of 250,000 BTUs, it is powerful enough to effectively warm large pools. This unit uses natural gas, making it an efficient option that can save on long-term energy costs. Its durable cupro nickel heat exchanger is designed to withstand corrosive conditions, which is beneficial for pools with unbalanced water chemistry.

The heater's hydraulic design aims to save energy by reducing the run time of the circulation pump, adding to its energy efficiency credentials. Additionally, it meets low NOx emissions standards, making it a more environmentally friendly choice. Installation and maintenance are simplified by its front-panel access and intuitive control pad, which users have found user-friendly. However, some may find the initial cost and weight (165 pounds) to be on the heavier and more expensive side. The product dimensions indicate it requires a fair amount of space for installation.

It’s ranked #6 in Swimming Pool Heaters, indicating it’s a popular and well-regarded choice in this category.

The Raypak 266,000 BTU Digital Electronic Ignition Natural Gas Pool Heater is a robust option for heating in-ground pools and spas. It operates on natural gas, making it efficient and suitable for various climates, especially colder regions where quick heating is necessary. With a heating capacity of 266,000 BTUs, it is powerful enough for medium to large-sized pools. The intermittent spark ignition system adds a layer of safety by only igniting when heat is required, which helps in saving energy and reducing operational costs.

The use of space-age materials ensures that the heater does not retain residual heat, allowing for installation without costly heat sinks, which is a significant benefit in terms of maintenance and installation costs. Additionally, the programmable thermostat enhances user convenience by allowing precise control over the pool temperature. However, at 210 pounds, it is relatively heavy and might require professional installation. Being a natural gas heater, it requires a gas line connection, which could be an additional installation consideration.

This heater is designed for outdoor use and is built to withstand various weather conditions, ensuring durability. It is suitable for users looking for a reliable and efficient heating solution for their pools or spas, but it is essential to consider the installation process and operational costs before purchasing.

The Raypak 206,000 BTU Digital Electronic Ignition Natural Gas Pool Heater is a strong contender in the in-ground pool heater category, especially for those seeking high efficiency and reliable performance. Its 206,000 BTU heating capacity makes it suitable for medium to large pools, providing ample heat output to maintain comfortable water temperatures. The digital electronic ignition ensures that the heater only uses gas when necessary, contributing to energy efficiency and cost savings over time.

Additionally, the heater's construction is designed to withstand various weather conditions, making it a versatile choice for different climates. The use of space-age materials prevents the heater from retaining residual heat, allowing for safer and potentially less expensive installation without the need for extra metal heat sinks. However, the unit's weight of 187 pounds and dimensions of 40 x 28 x 20 inches might make installation challenging, requiring professional help.