The Best Swimming Pool Heater in 2021

A Complete Pool Warmer Comparison Guide for Inground and Above Ground Pools

Do you want to find the best heater for your swimming pool? If so, then perhaps this article can help you out. A pool heater is an expensive investment for any pool owner. That is why you need to consider all the possible pool heater features and products on the market.

But first, you need to understand the importance of good water chemistry and a high-quality installation. If you don’t have these two things present, you will have problems with any pool heater. In fact, pool heater issues are the main problems that most people face with their pools. They simply don’t know how to take care of them. Either that or they don’t understand which pool heater products and brands are the most appropriate for their pools.

If you ask any pool technician about the common cause of pool heater problems, they would probably say the installation is faulty or the heater can’t handle the pool’s size. Therefore, your job is to study the features and specifications of the various high-quality pool heaters on the market. Once you find an excellent heater, hire a pool technician, gas heat technician or electrician to install it for you. Never attempt to install a pool heater by yourself. It is not a DIY project. It requires you to have gas, heat and electrical training.

The Top Most Recommended Pool Heaters

What makes someone choose one pool heater brand over another? Aren’t all pool heaters the same? Well, they are definitely not all the same. Pool heaters tend to have different technical features, some better than others. But you’ll usually have to pay more money for a technologically sophisticated pool heater. Does that mean it is necessary for your pool? Not always.

Don’t let the price or brand of a pool heater be the deciding factor in whether or not you buy it. Instead, study its features and specifications carefully.

Below are the top most recommended pool warmers.

The Best Gas Pool Heater

1. Hayward W3H250FDN Universal H-Series Pool Heater

The best pool heater that we could find is the Hayward W3H250FDN model. The pool heat warmer has a range of output between 150,000 and 400,000 BTU. It all depends on the pool size. Natural gas is required to power the heater. If you want an effective and environmentally-friendly pool heating solution, you won’t find anything better than the Hayward W3H250FDN. It satisfies all the necessary air-quality standards set forth by the government. The cupronickel heat exchanger stops corrosion before it strikes. Whether you have an inground swimming pool that uses cleaning chemicals or saltwater, this heat exchanger is the perfect addition to your pool. You’ll have the ability to manage the temperature on the digital control panel included. The control panel features LED technology, so it is easy to use in darker environments. You don’t necessarily need to have a newer swimming pool either. The Hayward W3H250FDN is compatible with older systems too.

Runner Up Gas Pool Heater

2. Raypak 206K BTU Natural Gas Pool Heater

If you like natural gas pool heaters, choose the Raypak 206K BTU Natural Gas Pool Heater. We believe it is one of the best natural gas pool heaters on the market. All you need is an existing natural gas line, and you’re good to go. The Raypak gas pool heater can accommodate a range of different sizes (between 206,000 and 406,000 BTUs). A galvanized metal cabinet feature adds durability, wind resistance, and corrosion resistance to the pool heater. Bad weather won’t damage your pool heater because it can resist most weather conditions. The electronic pilot ignition is highly reliable too. Do you like a pool heater that is easy to control? The electronic digital controls of this pool heater make it fast, convenient and straightforward to adjust the water temperature. Raypak designed this pool heater to be compatible with most pool control systems. But if you want to install the heater indoors, you’ll need to purchase a ventilation cover separately. That accessory is not included with the Raypak heater.

The Best Pool Heat Pump

Hayward HeatPro – 110,000 BTU Pool Heat Pump

Would you rather use an electric-powered pool heater? The Hayward HeatPro is the best electric inground pool heater on the market. It requires a 240V electrical connection for the delivery of 110,000 BTUs per hour. It takes warm air from the outside environment and places it into the water. According to Hayward, users can save up to 80% on their energy bills if they use the electric pool heater rather than a gas pool heater. The Hayward HeatPro has many impressive features to make it worthwhile, including a noise-reducing acoustic compressor, self-diagnostic system, digital control panel, and electronic frost controls. You won’t have any problem monitoring the performance or adjusting the temperature of your pool heater. They give you everything needed to manage your pool heat effectively.

The Best Solar Pool Heater

Smart Pool S601 Swimming Pool Solar Heater

How would you like to eliminate the energy costs associated with heating your pool? The Smart Pool S601 is the best pool heater that runs on solar energy. It is the perfect environmentally-friendly pool heater that can save you money and energy. The pool heater features multiple polypropylene panels that are 20’x’4 each. They can go on the roof of your home or the ground near your pool. As long as the heater connection can reach the pool filter, then it is within a close enough range. The polypropylene panels contain a series of channels. As the sun’s UV rays heat the panels, the water begins to heat up as it passes through them. The warm water circulates away from the panels and back into the pool, causing the pool water to heat up. You can expect up to a 15-degree increase in your pool temperature. Of course, you’ll have to wait for the sun to come out before the pool heater takes effect. But at least you don’t have to pay anything extra on your monthly energy bill. Operating the solar pool heater is free.

The Best Above Ground Swimming Pool Water Heater

Intex Solar Heater Mat

The Intex Solar Heater Mat is explicitly made for above ground swimming pools. Its dimensions are 47” x 47”, which can accommodate a smaller above ground pool. Since it is a solar heater, it will require the sun’s UV rays to heat the water. The water temperature will increase between 5 and 9°F. As long as you have no more than 8,000 gallons of water in your pool and a filter pump with 0.5 horsepower, you should not have any problems. Of course, you could always purchase several solar heater mats and put them together if you have a larger pool. You’re using the sun’s energy anyway so that it won’t affect your power bills at all.

The Top 5 Expectations for Owning a Pool Heater

When you purchase a new pool heater, you will probably expect it to last for a long time. But you must have realistic expectations and prepare for problems before they occur. Understand the possible causes of heating failure. Learn about the types of repairs and maintenance that may need to be done. It doesn’t matter which pool heater brand or product that you choose. You must have the same expectations regardless of the type of pool heater you buy.


Below are the top 5 expectations that everyone should have when they purchase a pool heater.

1) Poor Water Chemistry

Most pool owners don’t realize that water chemistry can impact the functionality of their pool heaters. If you don’t have the right amount of chlorine or pH in your pool water, it could reduce the longevity of your pool heater. Too much or too little pH, for example, could inflict long-term damage on the internal components of the heater. Keep this in mind and make water chemistry an important part of your pool maintenance work.

2) Zoned Bypass

When you don’t have balanced water chemistry, you can shut down your heater with something called a zoned bypass. Have a plumber install a zoned bypass in your plumbing system so that you can direct water away from the heater. Then you can just twist a valve handle to shut down your heater if the water chemistry is not balanced. This will ultimately protect your heater from possible damage.

3) Rodent Damage

Rodents are a common problem for pool owners. A few mice and rats could easily damage your pool heater if you don’t take the proper precautions. Many pool technicians recommend spraying WD40 onto the heater wires to deter rodents away from it. You can also use steel wool material to block entry into the heater.

When you’re done using the heater, shut down the power to it entirely. Don’t just push the off button on the control panel. You must actually shut down the circuit breaker for the pool heater. That way, there won’t be any heat or energy running through the wires or heater circuit. Rodents will stay away if there is no heat detected.

4) Winterizing

Winterizing means preparing your pool heater for the winter season. Drain all the water from the pool heater because it could freeze and damage its internal components. Take out the pressure switches and let the water drain from them too. Otherwise, they could freeze and break if any water is left in them during the colder months of the winter.

Don’t wrap a tarp over your heater because moisture will get trapped inside it. Then you will have to deal with corrosion, which could cause permanent damage to your heater. It is better to let air access the heater from the sides. If you want to cover the top, you could place a piece of wood onto it.

5) Flow Rates

Every pool heater has a recommended flow rate for maximum energy efficiency. If the flow rate starts to change, it can impact your energy expenses significantly. Don’t just choose a pool heater that has “energy-efficient” on the label. Install a flow meter onto your pool system to keep an eye on the flow rates carefully. With a variable speed pump or zone bypass valves installed, it is easy to modify the flow rate accordingly. Pool heater calibration is necessary for every heater.

An Overview of the Types of Pool Heaters

Should you purchase an electric pool heater, solar pool heater, or gas pool heater? Each heater has its pros and cons, such as the installation difficulty and operating expenses. Some of them also heat the water more quickly than others.

Let’s examine the three main types of pool heaters below.

1) Gas Pool Heaters

Gas pool heaters function just like the hot water heater in your home. It requires propane or natural gas to burn inside a combustion chamber. Once heat gets generated, it circulates from the chamber to the water. There must be a gas line connection for this heater to function. If you don’t have a gas line, then you’ll have to pay a hefty price for a professional to install one.

Gas pool heaters are the most expensive all around. The installation and long-term expenses might turn you away from them. However, the upside is that gas pool heaters can heat water quickly. They are the most potent pool heaters available. If you have a huge pool or live in a cold environment, then a gas pool heater is the best option for you.

2) Solar Pool Heaters

Solar pool heaters are environmentally friendly and eliminate your long-term energy expenses. They use heat from the sun to provide warmth to the pool water. When the sun’s UV rays hit the solar collectors of the heater, the thermal energy gets transferred to the water.

You will have no monthly expenses or maintenance expenses. Just install the solar panels and let them do the rest. Since there is no electricity or gas used, you won’t have to concern yourself with electrical outlets or gas lines. Therefore, you won’t be required to hire a professional plumber or electrician to assist you with the installation. Just let the sun provide the heat that your water needs to stay warm.

Solar pool heaters are ideal for warm and sunny environments. If you live in a cold location, then a solar pool heater won’t make much of a difference in your pool temperature.

3) Electric Pool Heaters

Electric pool heaters are the most popular among pool owners. They are energy-efficient, eco-friendly and have the capability of heating your pool quickly. The only downside is it will increase your monthly power bill. But if you choose an energy-efficient model, your power bill shouldn’t increase by that much.

Don’t expect an electric pool heater to work as fast as a gas pool heater. It will require a little more time for the pool water to heat up. That should be no big deal. Just plan your pool use time accordingly.

Frequently Asked Questions

Should you purchase an electric pool heater, solar pool heater, or gas pool heater? Each heater has its pros and cons, such as the installation difficulty and operating expenses. Some of them also heat the water more quickly than others.

Let’s examine the three main types of pool heaters below.

What Impact Does Climate Have on a Pool Heater?

Specific pool heater models require particular environmental conditions and temperatures to function correctly, such as sunlight for solar pool heaters. Climate can also impact how much energy you need to heat the pool water. Colder environments require more power than hotter environments.

Do I Need a Big Pool Heater?

Pool heaters come in different sizes. If you choose an electric or gas-powered heater, you need to understand the energy measurement known as British Thermal Units (BTU). This indicates how much energy is required to increase one pound of water by a single degree. If you increase the temperature significantly, you’ll consume a lot more energy.

High-quality residential pool heaters typically have a range of 50,000 to 75,000 BTUs.  A commercial size pool heater might get up to 450,000 BTUs. You can expect to pay more money if the BTU range is higher.

Which Pool Heater Should I Buy?

Think about the environmental conditions of where you live and the heat sources available at your home. Is it usually sunny in your location? If so, then try a less expensive solar pool heater. Solar covers are by far the cheapest pool heaters and have no ongoing expense.

But if you have a bigger pool with colder environmental conditions, then an electric or gas pool heater is recommended. Sure, you’ll have to pay more money, but your water will be warm and cozy. It all depends on how much you’re willing to spend for that comfort.

Raypak 406,000 BTU Digital Electronic Ignition Natural Gas Pool Heater
  • Part Number: 009219
  • Model Number: P-R406A-EN-C
  • LCD digital display provides accurate temperature
  • Monitors operational status as well as service diagnostics
  • High-wind resistance