Swimming Pool Heaters: How To Choose The Best One 

Swimming in March?  How about October?  Or November?  No way!!  But yes, way!!  Swimming pool heaters will allow you to s-t-r-e-t-c-h your swimming season out just a little further.  It could also be viewed as an investment and may increase the value of your pool should you choose to ever sell your home.  Many parts of the country don’t have the right combination of water and air temperatures to make swimming comfortable early or later in the season.  If you’re thinking of a couple more months of swimming, you may want to consider a good pool heater.

The secret is knowing what kinds of pool heater are on the market, how much they cost, and what they can do for you. 

Swimming Pool Heaters: How To Choose The Best One

What Is A Swimming Pool Heater?

Swimming pool heaters are just that, they heat and maintain your pool water to a comfortable temperature and are a popular way to heat your pool.  Pool heaters will use propane, natural gas, electricity to heat the water.  They generally have a lower upfront cost but do require the monthly cost of the energy type you choose. 

Why Should I Get A Pool Heater? 

Swimming pool heaters are a great way to extend your swimming season and may add value to your home.  A pool heater can be a very worthwhile investment if you and your family choose to utilize the pool year 'round, or perhaps you simply want a slightly longer swimming season.  It's also an excellent choice if your pool is shaded or it doesn't get full sun to help it naturally warm up. 

Your lifestyle should be taken into consideration.  If you don't plan on swimming that often, or only plan on using the pool during the hotter parts of the year, a swimming pool heater might not be for you.

Types Of Pool Heaters

So let's dive right in and start talking about one of the more popular types of pool heaters and that's an electric heat pump.

Electric Pool Heat Pumps

A pool heat pump uses electricity but doesn't generate heat.  Say what now?  Heat pumps have a fan which draws in heat from the outside air that has been warmed by the sun.  Pool water is drawn from the pool pump motor, goes through the filter and passes through the heat pump water heater.

The heat pump has its own heat with a fan that pulls in outside air and circulates the air through an outer evaporator coil.  The liquid refrigerant inside the coil absorbs the heat from the air and turns into a warm gas. 

The warm gas goes to the compressor which increases the heat, then make its way through a condenser.  It's the warm condensed gas that heats your pool.  Ah, now it's starting to make sense!!   

Cost Of An Electric Heat Pump

You'll pay a little more upfront for heat pumps and electric swimming pool heaters, but you'll also experience savings over gas heaters as the swimming season progresses.  Prices can vary, but you can expect to pay between $2000 - $3000 and up to $5000 for larger pools.  Geographical areas should also be taken into consideration.  I live in Florida and we have a very long swimming season compared to, let's say, Minnesota.  People up north will need to run their heat pump earlier and longer if they want to swim more.  You can go to this source to see the actual cost of heat pumps. 


  • Lower cost upfront.
  • No emissions.
  • Very reliable.
  • Can be run anytime of the year and in different weather conditions, compared to a solar heater.


  • Cost of operation is higher compared to other forms of pool heating.
  • Can take several hours to heat the pool a few degrees.
  • Higher back-end cost.
  • Cooler air temperatures will require longer heating times.
Easy pool maintenance

Solar Pool Heaters

We have the sun, right?  Let's put it to good use!!  Why not use its power and warmth to heat your pool?  That's a good question and more pool owners than ever are turning to this renewable source of endless energy.  The sun works 24/7 and never complains!!

Solar pool heaters work by using your pool pump motor (or a dedicated pump) to pass part of your pool water through a series of solar collectors that warm the water, then returns the warm water back to the pool.

Solar pool heater are both eco-friendly and affordable.  And they're certainly one of the best options for hotter area like here in Florida.  Even places that may only have a few months of swimming can benefit from solar pool heaters.

How Much Does a Solar Pool Heater Cost?

On average, a solar pool heating system will cost between $2,500 - $4,500 to buy and professionally install, but this can pay you back due to the energy savings you can experience.  And with an average lifespan of 15–20 years, they’re more durable than gas or heat pumps. 

How To Size A Solar Heater

When sizing a solar pool heater we need to consider a few things such as pool size, the desired temperature gain, and sun exposure, minus factors such as shade and tree obstruction.  Not all houses are good candidates for solar heaters.  You need to have a good amount of unobstructed roof space for at least 4 - 6 hours per day.

Expert solar panel installers suggest you should have half of the pool surface area dedicated in solar panels.   To find the surface area for your pool, simply multiply length x width of your pool.  For example, if you have an 18' x 32' pool, you'd have 576 sq. ft.  For round pools, the equation is pi x radius squared.  For a 24' round pool, the calculation is 3.14 x 144 = 452 sq. ft.  Pools that experience less sunny days, or windy conditions, might consider installing an extra panel or two to compensate for that loss.  

Pros Of A Solar Heater

  • Works very well in warmer areas.
  • Natural source of energy and eco-friendly.
  • Set it and forget it type of system.
  • Panels can last up to 20 years which is way longer than electric or gas pool heaters.

 Cons Of A Solar Heater

  • Lots of direct sunlight is needed for the panels to heat up enough.  They only work in direct sun.
  • Higher upfront cost.
  • You'll need lots of room on top of your house for the solar panels.
  • Panels can seem a bit unattractive.
  • Extra investment in a booster pump motor.

Gas Pool Heaters

Gas pool heaters are very simple to understand and use.  You can get them to run on either natural gas or propane.  A portion of your pool water passes through a type of combustion chamber that warms the water and is then returned back to the pool.

Gas pool heaters are the most efficient form of pool heating and ideal for quickly heating your pool.  Unlike heat pumps and solar heaters, gas heaters are able to better maintain a desired temperature regardless of the weather.

What’s The Average Price Of Gas Swimming Pool Heaters?

 Inground gas pool heaters can cost between $1200 - $3800, but this is really dependent upon some factors such as your pool size, how long you plan on using it, type of heater, and brand name.  For the monthly cost of gas, you can expect to spend $300 - $400 per month.  But again, this is also dependent upon many variables such as higher temperatures will require more gas, climate, usage, splash out and topping off with cooler water. 

What's The Right Size For A Gas Heater?

You'll first need to know the surface area of your pool as described above.  A good gas heater can add 1 - 2 degrees of heat per hour to the average pool.  For the best results, it's better to have a slightly larger heater for your pool.  This will not only heat your pool faster, it can save a little on gas due to it not needing to work as long to heat the water.  But, if you want to maintain a constant temperature by using a thermostat, a smaller size pool heater can be used. 

As a general rule for gas swimming pool heaters, you should expect have a:

  • 100 - 200 BTU heater to heat 1,000 - 10,000 gallons of pool water, or up to 300 sq. ft. 
  • 200 - 300 BTU heater to heat 10,000 - 20,000 gallons of water, or up to 500 sq. ft.
  • 300 - 400 BTU heater to heat 20,000 - 40,000 gallons of water, or up to 800 sq. ft.
  • 400 BTU heater to heat 40,000 - 80,000 gallons of water, or up to 1200 sq. ft.


  • Extremely efficient at quickly warming your pool.
  • They don't have to run as much compared to other types of heating.
  • They usually experience fewer problems with wear and tear.
  • When gas prices are low, they can be less expensive to operate compared to electric pool heaters.


  • Somewhat expensive to install.
  • Installing a gas heater requires extra plumbing such as metal lines below the ground.
  • Gas prices often fluctuate which means low cost this Summer might be higher gas cost next Summer.
  • Repairs to gas heaters are usually not recommended for DIYers.  Calling in a professional tech can cost hundreds for severe problems.  Tinkering with swimming pool heaters is not something you want to do.

Use A Solar Cover For Better Pool Heating

How does adding a few more degrees to you pool sound?  What if I said you could do this for pennies on the dollar?  Even better?  Then I suggest investing in a solar pool cover.  As we know, heat rises and water evaporates.  A solar cover placed on your pool will retain more heat and reduce evaporation, giving you more bang for your buck. 

A solar cover acts like an insulation barrier, trapping the heat inside your pool.  Your pool heater won't need to work as hard or as long to heat your pool to your desired temperature.  And the savings in water and energy will more than pay for it in a short period of time.  Less evaporation and less chemical use means more money in your pocket.  And we all could use that, right?   

How To Choose The Best Swimming Pool Heater

Choosing the best pool heater depends on many factors such as location, budget, and the size of your pool.  Here are some general rules to follow, then adjust to your specific needs: 

  • In warmer climates, a solar heater with a solar cover is good.
  • In cooler climates, natural gas with a solar cover.
  • In cooler climates without access to natural gas, go with a heat pump.  And remember your solar cover. 

Whatever type of pool heater you decide on, it’s recommended to consult a pool contractor or pool heating expert prior to making your purchase.

Easy pool chemistry

Are Swimming Pool Heaters Worth It? 

There are some "ifs" here that only you can answer.  If your pool does not receive full sun during the day, or if you want to swim earlier and later in the season, a pool heater might be worth the investment.  Just because it's getting a little cooler outside doesn't mean you can't enjoy your pool.  Choose the best swimming pool heater for your pool and budget and have fun swimming.