Find the best pool heater and everything you need to know before you buy in this guide.
Swimming pool heaters will keep your pool’s water at the optimum temperature so that you can take a dip whenever you like. There are a few different types of pool heaters to choose from.
First of all, there are in-ground pool heaters and above ground swimming pool heaters, so the type you need will depend on the style of your pool. After this you’ll have a selection of heater varieties to pick from: eco-friendly solar pool heaters, gas pool heaters, and electric pool heaters are all available and come at different costs and energy usage levels.
Gas heaters are typically the most powerful and can heat up the water in your swimming pool faster than an electric heater. The downside to gas pool heaters is that they can be much noisier than other models and they do sometimes have harmful emissions. A final option is a tankless model, such as the EcoSmart Smart Pool 18 pool heater, which has the added benefit of being much more compact.
For larger pools, a gas heater will work faster to heat up the water, but regardless of which type of heater you opt for, a solar pool cover will help to keep the heat in your water when you’re not using the pool, which is a cost and energy saving option, long term.
How much do pool heaters cost? The swimming pool heaters in our guide range from hundreds of dollars up to well over $4,000, but it’s also important to account for the running costs too. Take a look at our pool heater reviews below and find one that suits your needs.
1. Pentair 460737 MasterTemp: Best propane pool heater
This propane gas pool heater heats up quickly so you won’t have to wait around for hours before taking the plunge. It’s certified for low NOx emission and outperforms industry standards. It has a rotating digital display so it’s easy to view, and user-friendly indicator lights help make it easy to both operate and monitor performance. The tough, rustproof exterior is designed to withstand all weathers, extending its longevity. The compact design and quiet operation mean you can swim in peace – it hardly makes a sound, so it won’t intrude on your poolside enjoyment.
- Read our Pentair 460737 MasterTemp review
2. EcoSmart Smart Pool 18: Best electric pool heater
This differs from other electric pool heaters in so far as it’s an electric tankless heater. Instead of traditional pressure switch activation, the EcoSmart Smart Pool 18 uses flow sensor technology, which increases its reliability and longevity and also reduces the risk of elements burning out. The EcoSmart Smart Pool 18 electric pool heater has a digital temperature display and dial that lets you set your preferred water temperature in 1-degree increments. It can be used as an alternative to a heat pump or as a booster. It’s compact and lightweight, and it’s energy-efficient – no matter what the ambient temperature.
- Read our EcoSmart Smart Pool 18 review
3. Hayward HeatPro HP21404T: Most economical pool heater
This HeatPro electric heat pump is ideal if you’re looking for an electric pool heater that will allow you to extend your pool season. It uses the outside air together with a titanium heat exchanger and profiled fan blade to generate heat for a fraction of the cost of gas pool heaters. The manufacturers say you could save up to 80% on your pool operating costs. As well as being energy efficient, it’s also easy to install and quiet to run, so you can enjoy your pool and backyard without the intrusion associated with a noisy pool heater.
- Read our Hayward HeatPro HP21404T review
4. Hayward H-Series H250FDN: Best natural gas pool heater
The Hayward H-Series H250FDN is an energy efficient, high performance natural gas pool heater. The hydraulic design reduces circulation pump run time. It’s an environmentally friendly option for a gas heater as it produces low NOx emissions. This heater has a standard cupro nickel heat exchanger and offers ultimate installation flexibility on new or existing equipment pads. The forced draft system moves air through the combustion chamber at a precise flow rate, eliminating the outside weather variables that can affect the performance of a gas pool heater.
- Read our Hayward H-Series H250FDN review
5. SmartPool SunHeater S120U: Best solar pool heater
If you’re looking for an eco-friendly, cost-effective way to heat your pool, we think this is it. The universal system is suitable for in-ground or above ground pools, and this solar pool heater could not be easier to install – it’s designed to be placed on your roof, ground or fence, and it works in conjunction with your existing pool pump. This solar pool heater captures heat from the sun’s rays and can raise the temperature of the water in your pool by 6-10 degrees Fahrenheit, adding weeks to your pool season.
- Read our SmartPool SunHeater S120U review
Which type of pool heater should you choose?
Understanding how each type of pool heater works isn’t rocket science but a basic grasp of the logistics will help you choose the best heater for your pool. There are three main types of pool heaters; gas pool heaters, electric pool heaters (including heat pumps) and solar powered pool heaters. The difference between them is the power source they use, but this affects everything from the installation process to the running costs, as well as which climates they are appropriate for.
Gas pool heaters
A gas pool heater runs in a similar way to your home’s hot water heater – it burns natural gas or propane in a combustion chamber and transfers that heat to the water as it circulates through the heater. It has to be connected to a gas line through an underground gas pipe. This means that while the initial upfront cost may be lower than other types of pool heater, the installation costs are usually higher. And depending on the location of your nearest gas source, installation can even be prohibitively costly.
In addition to the added installation cost, the ongoing running cost of a gas pool heater is higher. The price of gas, which fluctuates, will determine the exact ongoing cost of running a gas pool heater.
Gas pool heaters are more powerful than other types of pool heater, so they’re good for heating bigger pools that hold a large volume of water, and useful if you want to heat your pool in a hurry. They’re also ideal if you live in a cooler climate, or if you intend to heat the pool occasionally and for short periods. If you’re looking for an eco-friendly way to heat your pool, however, a gas pool heater is not the answer.
Solar Pool Heaters
A solar pool heater is the most planet-friendly way to heat your pool. Unlike other types of pool heater, solar pool heaters use natural energy sources, making them the most economical option. A solar pool heater uses solar collectors to transfer the thermal energy of the sun to the water in the pool. You place the solar collectors near to the pool pump, so the heat is transferred to the water as it’s pumped into the pool. Once you’ve installed a solar pool heater, you’ll have almost no maintenance costs and no monthly operating costs. Once the panels are in place, you can sit back and let the sun do its job.
A solar pool heater is very easy to install. They don’t need to be connected to any kind of energy outlet, so you won’t need to hire an installer. They work slowly compared to a gas pool heater, but once the pool reaches the desired temperature, it’s easy to keep it there – just remember to ensure that both your pool and the solar collectors get plenty of sunlight and aren’t located in a shaded area. This type of heater is best suited to warmer climates that get plenty of sun. If you want to use the pool at night without experiencing colder water, you may need to purchase a diverter, so factor in the additional cost of this.
Electric Pool Heaters
As you might expect, electric pool heaters are the most popular type of pool heater, and arguably the most efficient. As well as performing consistently year-round, an electric pool heater is the fastest way to heat your pool. You’ll obviously have monthly costs with an electric pool heater – factor in that your electricity bill will go up – but you’ll spend less per month if you go for an energy-efficient electric pool heater, compared to one that’s cheaper to buy but has higher running costs.
Electric heat pumps are more eco-friendly than gas pool heaters as they use the ambient temperature to heat the water. They don’t need to be connected to a gas line, so they're also easier to install than gas pool heaters. Electric heat pumps raise your pool’s temperature less quickly than gas pool heaters, but they can be kept running longer for less money, so they’re more cost-effective if you want to use your pool every day.
As we’ve explained, some models of pool heater rely on the ambient temperature or sunlight to heat the pool, so climate is a key factor in determining which pool heater is right for you. The climate also affects the energy requirements you need when calculating the power requirements for heating your pool.
What size pool heater should you get?
Whether you want a gas, electric or solar pool heater, choosing the correct size heater for your pool is important. Gas and electric heaters are measured in BTU, or British Thermal Units. That’s the amount of energy it takes to raise one pound of water by one degree. The more you have to raise the temperature by, the more energy you need. It’s worth checking out one of the helpful calculators online to help you calculate the BTU you need in a pool heater. Consult a pool pro for more specific guidance.