Whether you have an above ground or an inground pool, a pool heater can really extend your swimming season. With so many options to choose from, picking the right heater for your pool can be overwhelming. Let us take the guesswork out of it for you, as we break down the different types of pool heaters and help you choose the right one for your unique swimming pool.

Types of Pool Heaters

The first thing to consider when choosing a pool heater is the power source. There are a few different types of pool heaters to choose from including: gas heaters, which get their power from natural gas or propane; electric heaters and heat pumps which run off of electricity; and solar heaters which use energy from the sun to heat the pool. Each type of heater has its pros and cons.

Gas Pool Heaters

Gas pool heaters are the most popular option because they are the fastest type of pool heater. Gas heaters can add 1 - 3 degrees F per hour to the water temperature. They are also preferred in colder environments, as gas heaters are able to raise water temperatures year round, even when air temperatures are significantly colder. Gas heaters are considered the best option for large pools in colder climates.

In order to install a gas pool heater, a natural gas line or propane tank is required. While natural gas is relatively inexpensive, propane gas is pricier, and you will need to have it delivered regularly. These types of pool heaters are not as eco-friendly as electric pool heaters, but they do cost less to operate. New models are increasingly environmentally friendly. Look for the low NOx emissions label for a more energy efficient model.

Electric Pool Heaters

Electric pool heaters are only recommended for very small pools and hot tubs, as they heat the pool water much more slowly (1 - 3 degrees F per day). They are great for small spaces, as the units themselves are usually much smaller than gas heaters. While they are inexpensive to purchase, electric heaters have high operating costs, and do not work well in cold temperatures.

In electric pool heaters, a resistor element is immersed in a heating chamber, where it heats the water as it passes through. They require a 240 V outlet that is located close to the pool area, and may even require some changes to your electrical panel.

Heat Pumps

Heat pumps also run off of electricity and require a 240 V outlet, but they work in a different way, extracting heat from the surrounding air and employing an evaporator, compressor, and condenser to heat the water.

Other than solar heaters, heat pumps are widely considered the most eco-friendly option in pool heaters, as they require very little electricity to run day-to-day. Units are quiet, small, and very energy efficient. They are, however, more expensive to purchase up front and do not work as well if the outside air temperature is below 60 degrees Fahrenheit.

Solar Pool Heaters

Finally, solar pool heaters are of course the greenest option available, using only the sun’s energy to warm the pool water. A solar heater uses solar panels to collect the heat from the sun. The heat is stored in solar collectors, then water is pumped from the pool into the collectors, where it is heated and returned to the pool.

Solar heaters take much longer to raise the pool temperature than other types of pool heaters. The downside of solar panels is that they cannot work at night and they are much less effective on cloudy and cold days. The solar panels require a large amount of space and should be professionally installed.

While solar heaters can be expensive to install, they are extremely durable, having a lifespan of twenty years or more, and they cost nothing to run.

Pool Talk: What To Consider When Buying a Pool Heater

Above Ground Pool Heaters vs Inground Pool Heaters

Some pool heaters are made specifically for above ground pools, and others are made for inground pools. The difference is really about size. Above ground pools are generally smaller than most inground pools, so they require a smaller heating system. Since inground pools are usually larger, they require more BTUs for efficient heating.

How to Choose the Right Size Pool Heater

Now that you understand the different types of heaters, you still need to determine which size is best for your pool. The amount of heat produced by a pool heater is measured in BTUs (British Thermal Units). BTU ratings range from about 45,000 BTUs for smaller above ground pools to 500,000 for very large inground pools. The BTU output required depends on the size of the pool, in gallons.

As a general rule, gas pool heaters should have about 100,000 BTUs per 10,000 gallons of water. In especially cold climates, or if you do not use a pool cover, you may need slightly more. Heat pump sizing is similar to gas, but with a heat pump, higher BTUs usually mean faster water heating.

To determine what size solar pool heater you need, the solar panels should take up at least 50% of the surface area of the pool. If you do not live in a place with ideal conditions for solar panels, it should be closer to 75%.

Doheny’s Recommended Above Ground Pool Heaters

Hayward Universal H-Series 250K BTU - This heater comes in both natural gas and propane models, and is ideal for pools up to 18,000 gallons. Low NOx emissions certified with choice of left-side or right-side electric, gas and water connections for ultimate flexibility.

Hayward HeatPro 50K - Adds consistent, reliable heating to any above ground pool. It delivers ideal water temperatures—even under harsh conditions—ensuring a comfortable swimming experience no matter the time of day. Plus, its durable design gets the swim season off to an earlier start in the spring while also extending it later into the fall.

Doheny’s Above Ground Pool Solar Heating System - This system features easy to install solar panels and runs off of your existing pool pump for money-saving results. Heat pool temperatures up to 10 degrees with just the sun’s energy.

Doheny’s Recommended Inground Pool Heaters

Hayward Universal H-Series 400K BTU - Hayward Universal H-Series heaters have the flexibility to provide an energy-efficient and environmentally responsible low NOx performance solution for pools and spas.

Hayward HeatPro Heat Pump - This unit is small in size but big in energy efficiency. It features a titanium heat exchanger and corrosion resistant housing for maximum durability.

Doheny’s Inground Pool Solar Heating System - Warm your pool water by 10 - 15 degrees with this easy to install solar heating system designed for inground pools. Works with your existing pool pump.

When you have the right pool heater, your swim season can be longer and more enjoyable. The pros at Doheny’s are here to help you choose the best heater for your pool, so give us a call today at 800-574-7665 or check us out on the web at doheny.com.

For more swimming pool equipment, don't forget to look at our above ground pool cleaners, in-ground pool pumps, and winter closing kits.