Swimming Pool Heaters Buying Guide – Choosing the Best Type & Models
(updated 2018)

Swimming pool heaters buying tips. Review of the gas, electric and solar pool heaters including heat pumps. Check out popular models from Hayward, Raypak, AquaCal, Jandy and Pentair; for above ground and in-ground pools.

Swimming pool heaters are efficient and cost-effective devices to heat pool water, but they are not easy to choose in any way. If you are looking for the right water heating choice for your pool, either above ground or in-ground, here we have great options for you to consider!

Being able to get in the pool even when it is not the time/weather such as in May, September even October, and extend the swimming season, is an advantage not everyone can enjoy. That’s why swimming pool heaters exist, to bring more enjoyment to people who would prefer to have longer seasons, avoid indoor swimming, or to be able to control the temperature of the pool water, while not depending on nature only.

Here we are going to show you important tips when selecting/buying pool heaters – so you can buy a good product and make your swimming pool cozier without problems, and eventually save…

Benefits of using swimming pool heaters

Extend the swimming season. Swimming pool heaters can help you control the temperature of your pool water so you can enjoy swimming longer and in months when most of the pools are closed.

Increase property value. People like comfort and convenience, and that is why they prefer or would pay more for the house that has a heated pool. At least I would. And, if money is not an object.

Comfort and convenience. Instead of going to the public indoor pools, by using your own heated pool you can enjoy swimming at home, in a clean pool, away from the crowd, avoiding driving, parking, and busy traffic. The kids can be watched safely without catching the viruses and bacteria in the public pools. As the water temperature is controlled only by you, they don’t get affected by the unpleasantly lower temperatures as found in public ones. Also did we mention high levels of chlorine in those pools?

Free operating costs and low maintenance. Some pool heaters, such as those powered by solar energy are using free, renewable energy from the Sun. You just have to buy the panels. Energy savings and environmental protection are guaranteed.

Types of swimming pool heaters

Just as there are different types of water heaters for home, there are also various types of heaters for pools. Choose the one that fits your needs.

Gas or propane swimming pool heaters

Hayward gas pool heaterHayward gas pool heater

Gas pool water heaters are the most common and maybe the preferred by most pool users. What makes them so likable are the ability to heat the pool water faster than any other type of heaters, efficiency (new models) price, but could eventually have a higher cost in the long run, especially propane type. These tend to be pretty reliable nonetheless, offering a lifespan of up to 15 years in the best case scenario.

An ideal situation for a gas or propane heater would be in pools that are not used daily or quite often. Propane gas, for example, tends to be quite expensive and will probably become a problem for your wallet. Keep in mind that propane gas cost more than natural gas. But if you can afford propane or natural gas heater, there’s no doubt you will enjoy it a lot more.

By using a combustion heating system, they are much faster and efficient, no matter the temperature of the water or the weather. The greatest benefit of gas pool heaters is the powerful gas burner and speed of heating.

If you think of getting a natural gas or propane heater, make sure it is a new model using the latest advanced features. New models are much more energy-efficient and will not harm the environment as much. These new models usually come with a “Low NOX” feature which makes them Eco-friendlier. This feature or low-NOx emission is required in California and Texas. A great example is Hayward H250FDN from H-Series.

The size of these heaters is measured in BTUs. BTU stands for British thermal unit, and it shows the amount of heat that is created by a device. This part is critical, as you will very likely have to choose the right heater according to how much BTUs you’ll need.  Most of these heaters come with sizes rounding the 100,000 BTUs for small pools and up to 500,000 BTUs for the largest ones.

These heaters are affordable at first. They can cost from $1500 up to $3500 in the biggest ones. However, in heavily used pools they may cost more than $600 per month.


  • Heats water fast
  • Can be used in almost any climate
  • Not expensive as heat pumps
  • Durable


  • Need natural gas or propane (more expensive) supply
  • More installation work and costs
  • Pollution
  • Propane is expensive. Needs propane tank for supply and regular delivery

Electric swimming pool heaters

The good thing about electric heaters is that they take a lot less space than other types, are often small, and can be turned on and off without problems. However, in the long run, they could be the costliest, even more than gas heaters, because the electricity costs much more than gas.

An electric heater heats the water by using a resistor element that uses electrical current to generate heat, eventually heating the water that passes around. This water is pumped out of the device and into the pool. This method, despite being effective for heating water, uses so much electricity that could become a real problem for the wallet. Your house might need some electrical panel modifications.

They can cost up to $600 or even more a month for pools that are used more than five days a week. This makes them undesirable for most people unless you can handle the cost. They don’t last too long either, as they tend to fail in the first ten years, and last up to 15 for the luckiest users. For those who can afford it, however, an electric water heater will be fantastic as they can be used almost anywhere at any time and receive excellent results nonetheless.

That’s why electric heaters are mostly recommended for small pools, spas, hot tubs or where there is no need to heat up for long. They can cost as little as $500 but can go up to $5000 in the most efficient or powerful devices. And when it comes to installation, the cost may go up even further.


  • Cheap
  • Clean
  • Small
  • Easy to use
  • Can work in any weather
  • Reliable technology


  • High operating costs
  • High installation costs
  • Do not heat water fast
  • Low efficiency
  • Short lifespan

Recommended model to buy

Heat pump pool heaters

Heat pumps may be the “greenest” approach to heaters for pools available in the market behind solar heaters. They are easy to install and use while being a lot cheaper for operation. 

A heat pump is extracting heat from the surrounding warm air, compresses the heated refrigerant inside with a compressor, and then heating the water with the hot compressed refrigerant while throwing the cold air out the top of the appliance.

These heaters last a little longer to heat the water than others, especially when compared to gas heaters. However, in the long run, they could become a lot more efficient and useful, especially in warm to hot environments. The minimum temperature needed to use a heat pump heater is 45 degrees Fahrenheit, anything lower than that will make this type of the heating device, inefficient.

At first, heat pumps can be more expensive than other heaters, as they heat water differently. However, the operation cost of these heaters is little to not existent. And what’s even better, they can last up to 20 years without breaking.

Buying one the less powerful heat pump heaters may cost as little as $1,800, but can go up to $5,000 in the biggest and most effective ones.


  • Low operating costs
  • Clean and environment-friendly
  • Quiet
  • High efficiency
  • Easy to use
  • It can provide both heating and cooling
  • Reliable
  • Great for larger pools


  • Disadvantages
  • Lower efficiency with the lower outside temperature
  • Expensive

Recommended model to buy

Solar pool heaters

Solar energy is the greenest and most energy-efficient method for domestic and pool water heating known. It uses solar panels to harvest solar heat which is eventually stored in collectors. Water is pumped into the solar panels’ collectors and out again towards the pool when it is heated. This demands not only more installation efforts but a lot more time to heat the water. In the long run, however, they are a lot more affordable to use.

The problem with these heaters is that they can’t be used at night or when there aren’t many sun rays to heat the panels. In winter or cloudy places, solar panel heaters are used, but with the reduced efficiency, so backup heaters are recommended. During the cold weather, the water may not heat up efficiently as the process lasts longer than a heat pump, which is slower than electric and gas heaters.

If you think this one fits your needs still, make sure you have enough space to install the solar panels. They take a lot of room and most of the time need an expert to evaluate the place before installation. Despite being a little more complicated to install, the cost of installation may still be lower than an electric heater.

A solar panel heater price may range from $2,500 up to $4,000, including installation costs. This price range is for the glazed type. Cheaper options are flexible ones (unglazed) which usually come as the DIY kit, and they do not require professional installation.

And, of course, they don’t cost anything to operate while offering a lifespan of up to 20 years without breaking.


  • Very low operating cost
  • Environment-friendly operation
  • Low maintenance


  • High purchase cost
  • High installation cost
  • Hard to control the water temperature
  • Can damage the roof (can develop leaks)
  • Glazing (tempered glass) can break

Cost of service

According to the AquaCal manufacturer of swimming pool heaters, heat pumps are the cheapest to operate, mainly due to its high energy efficiency. AquaCal heat pumps have the cost of operation of $6.25 per million BTUs of heat. The next ones are the natural gas pool heaters, with the price of $27.50, then heaters using the electricity ($38.10) while the most expensive are heaters using the propane gas - $40.76.

This comparison cost is based on the following prices: $3 for a gallon of LP gas, $2.20 natural gas, 13 cents per kilowatt, where the heat pump’s Coefficient of Performance (COP) is 6.1.

Yes, the heat pumps are the favorable heating method, but upfront costs and long-term costs can affect this decision.

Selecting tips

Popular manufacturers

Picking the right size for pool water heaters

The right size of a pool heater is all about how powerful it is and whether it can heat your pool per specs. This is done by calculating BTUs and overall needed capacity.

Calculating gas heater size

First, consider the temperature you want the pool to be heated up to. Then find out what’s the average temperature outside, taking into account the coldest month.

Second, subtract the average temperature for the coldest month outside your home from the desired temperature for your water heater. This will give you the temperature rise.

Third, calculate the pool area in square feet. You can do this by multiplying both the length and the width of the pool if it is rectangular or RxRx3.14 for the round size (R-radius of the pool).

Fourth, use both the temperature rise measure and the total pool square feet area multiplied by 12 to get the total BTU you need. For example, 20 x 500 x 12 = 120,000 BTU you will need for your heater.

Calculating electric heater size

Electric heaters are similar to gas heaters when it comes to calculating the size. However, it is important to note that these are often a little faster in heating the water if more BTU they offer. This means that any device with more than 200,000 BTU will be a lot more efficient in the long run than a gas water heater.

Calculating heat pump heater size

Heat pumps are also pretty similar to electric and gas water heaters as they also use BTU as the power measurement. However, they also tend to use horsepower (HP), which correlates with the amount of BTU of the device. For 75,000 BTU, make sure it offers at least 3.5 HP, for 100,000 BTU you should go for 5 HP, and for 125,000 BTU or more it should have at least 6 HP up to 8 HP in the most powerful ones.

Calculating solar heater size

Solar heaters are an entirely different thing when it comes to calculating size. They are often much more space deficient as they take up to 75% of the entire pool area. This means that if your pool takes 1000 square feet of space, your solar panel area should be at least 700 square feet. Seems like a lot, and it is. For cold environments, it is recommended to go for 100% of the square area of the pool, this way you will be able to meet your temperature requirements.

Which pool water heaters are better for you?

It all comes down to the place where you live and climate, your energy source availability, and financial capacity you can afford for the device that best suits your needs. Choose your water heating device taking into consideration the above suggestions and tips, and you’ll surely make the right buying decision.

Don’t let a cold pool turn you away from enjoying a nice swim. If you live in the northern regions or own a business such as a hotel, motel, gym, you definitely want to buy a pool heater, for the extended swimming season. As the natural gas type heaters heat water very fast, they are the recommended type, but if you leave in the southern regions, buy a heat pump and see how water can be efficiently heated.

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