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Swimming Pool Heating

The best way to increase the enjoyment and usage of your pool, as well as extend the swimming season is to install a heater.  Our customers that get the most frequent use and enjoyment from their pools have heaters .  Speaking from personal experience, we went two years without a heater and our pool was rarely used.  When we had pool parties, people would jump in to cool down and then exit the pool after a few minutes because it was too cold to stay in for very long.  The season we started heating the water, the pool got almost daily use and people stayed in the pool for HOURS when they came over.  


Some pools that are in direct sunlight all day can naturally heat up to a decent temperature during July and August.  However, for the majority of pools not in direct sunlight or for the other months (April, May, June, and September) the pool is usually too cold to swim comfortably.  Here is some information to consider about the various methods of heating the pool: 

(Please keep in mind that any cost estimates are generic and subject to change due to changes in utility costs, etc.)

Solar Heating

Given the potentially high cost of heating with gas, people often wonder about other more economical options to heating the pool.  Accordingly, solar heating is one of the topics we get most frequently asked about.  As solar energy has increased in efficiency and popularity for home electrical usage and home hydronic heating, the appeal for swimming pool solar heating has increased as well.  I, personally, am an environmentally conscious person and look for green solutions as often as possible.  When it was time to install a heater for our pool, my first choice was solar.  I figured it would be a great opportunity to install a solar heating system to test out so we could inform our customers and provide a viable option for cost-effective heating.  I spent an entire winter researching, taking industry classes on solar heating, and talking to various manufacturers.  At the end of that process I walked away understanding the complications and limitations of solar and feeling that the technology hasn’t advanced enough to make it worthwhile.


The main concerns with solar are:

1.  In order for solar heating to be effective you need solar heating panels AT LEAST the size of the pool or preferably 150% the size of the pool.  This presents a couple of problems:

a.  You would need a south-facing roof area that is as large or larger than your pool completely covered with solar panels.  Most people don’t have that much south-facing roof area.

b.  This represents a very large number of solar panels which are necessary.  The cost for this many solar panels is quite expensive.

c.  If a smaller array of panels is installed it won’t be effective at heating the pool.

2.  Solar panels need to be installed in the roof.  Leaking, damage to the roof, and wind-related problems, can result from installation of the solar panels.

3.  In order for the panels to heat the pool when it is warm and NOT cool the pool when it is colder a system of sensors, relays, actuated valves, and controls needs to be installed.  These controls are costly and if system is installed without them then the panels will cool the pool on a cloudy day or any time the panels are cooler than the pool temperature.

4.  Despite advances in solar electric home hydronic heating, there have not been significant advances in solar pool heating in recent years.  Given the large volume of the pool and the relative inefficiency of the solar heating panels, it takes pretty consistent sunny weather to adequately heat the pool.  If there a few cloudy days leading up to the date of your pool party or holiday weekend then the pool will likely not be at the proper temperature.

All of this being taken into account means that to adequately heat with solar the average pool owner is looking at the following statistics:

1.  $12,500 – $20,000 investment for a properly sized and controlled solar heating system


2.  Potential complications with where the solar panels get installed and roof issues down the line


3.  Very poor heating / net zero gain for an inexpensive or undersized system that does not have controllers


4.  Poor heating during months when it is cooler (April, May, June, and September)


5.  Poor heating during cloudy, rainy, cooler days

The situation for our pool to have solar heat was almost an ideal one (building with enough south facing roof to install all of the panels, etc), but even at that the expense and the heating limitations made it not worthwhile to install.

Gas Heating

Gas heating was the primary source for pool heating for many years.  Gas heating can still be a good option for certain situations.  Here are some pros and cons of gas heating.


1.  Gas heaters heat the pool the fastest.  As a result pools can be “spot heated” for just specific weekends or holidays which can be an cost-effective option for heating the pool.

2.  Propane heaters can be installed anywhere

3.  Gas heaters are the least expensive in terms of the initial cost of the unit


1.  Gas is the most expensive option in terms of ongoing cost.  Propane costs on average about $4 to generate 100k BTUs of heat.  Natural gas is more affordable at about $2 per 100k btu of heat, but still twice as expensive as heating with a heat pump

2.  Running gas lines to the heater can be extremely expensive and can offset the savings for the cost of the unit

3.  Older gas heaters often had insufficient gas lines which sometimes need to be replaced with larger gas lines to accommodate a modern heater.

4.  Consistent heating throughout the season can be very expensive

​The net result is that gas heaters can be a good heating option if the existing infrastructure is in place and if you are looking to heat the pool only occasionally throughout the season.

Heat Pumps

15 years ago heat pumps were a product that worked only in a warm climate like Florida or California.  Advances in technology have since made this perfectly suited for heating a pool in New England.  Heat pumps can work throughout the season (April – October) in New England and have peak efficiency from mid-May through mid-September.  A majority of our customers 80% – 90% now choose heat pumps to heat their pools.



1.  Heat Pumps are much more economical to operate than gas heaters.  Heat Pumps cost about $1 for 100k btu of heat (which is half of what Natural Gas costs and a QUARTER of what propane costs)


2.  Require no gas line to be run


3.  Heat pumps are extremely efficient and effective at consistently maintaining a temperature throughout the season



1.  Heat pumps require a large electrical line.  If existing electrical service at the filter system is insufficient running a new electrical line can be costly (especially if the system is a long way from the house or the electrical panel.)

2.  Heat pumps take longer to initially heat the pool (a couple of days instead of a day) so they are not recommended for “spot heating”

3.  The initial cost of the unit is slightly higher than a gas heater unit

Final Thoughts

After weighing all of the options for our pool we decided to go ahead with a heat pump and have been very happy with the results.  The heat pump costs about $125 a month to run on our pool (with a temperature of 85 degrees).  The majority of customers now are going with heat pumps versus the other heating options.  Of the 500+ pools we service, less than 5 have solar heating and the pools generally are not much warmer than non-heated pools.  Some customers still choose gas heaters which can be a good option if the existing infrastructure is in place and if the pool is only going to be heated for specific weekends throughout the summer.  Regardless of what heating option you decide will work best for your swimming pool, Atlantis Pool Service is happy to help you out!

The descriptions and wording contained on this webpage are exclusively the property of Bryan Mills / Atlantis Pool Service LLC.  Any reproduction or use without the consent of Atlantis Pool Service is strictly prohibited.

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