Mar 27

In-ground Pool Heaters: Electric vs. Gas Comparison

Every year as we drift closer to spring time in New England we start getting calls from pool owners about installing a new pool heater. When people start thinking about extending their pool season with a heated in-ground pool they want to know what their options are and what will best fit their needs.

Today there are two main options for in-ground pool heaters; gas fired heaters and electric heat pumps. Gas fired heaters have been the staple here in the north east for some time now, but with the rising costs of propane and natural gas, as well as advances in electric heat pump technology, heat pumps are starting to become more prevalent in the area.

Pentair Pool Equipment Massachusetts

Below I have layed out some of the major differences between the two options. I won’t go into too much technical details within the article but if you have specific questions please leave a comment below and I will be happy to answer them for you.

>Gas fired heater Pros

  • Heats up fast, and you only need to run pool heater when you want to swim
  • Can extend the pool season in the cooler months regardless of outside temperature
  • Less up front cost

Gas fired Pool heater Cons

  • Requires use of expensive propane or natural gas fuel making for higher operating costs
  • If you don’t have natural gas at your home you will need to set up large propane tanks on the property
  • Due to the many gas plumbing parts, maintenance and repairs tend to be expensive

Electric Pool heater pump pros

  • Lower operating costs
  • Environmentally friendly
  • Continuous heat flow and even temperature

Electric heater pump cons

  • Higher upfront costs
  • Does not heat up fast must run continuously to maintain temperature
  • Can not run in cooler weather months, average temp must be above 45 degrees to operate

Over the last couple of pool seasons we have been installing more and more heat pumps on in-ground pools, but that does not mean people are abandoning gas pool heaters altogether. How you heat your pool all depends on how your pool is used throughout the year.

Due to the speed at which a gas pool heater can raise the temperature of the pool water, you may opt for a gas heater if your pool only gets used on weekends or, just a couple times a week. This way you only have to run the heater when you want to use the pool, just fire it up in the morning and enjoy a comfortable swimming temperature for your afternoon fun. In this case the higher operating costs won’t be much of a factor because you are not running the gas heater that frequently. Also if you really want to extend your pool season and enjoy your pool from April to November the gas option might work for you, as when the temperature drops in these cooler months the heat pump will not maintain the pool water nearly as well as a gas heater.

If your pool gets a lot of use and people are in and out daily or many times a week, the lower operating costs of the electric heat pump might be more beneficial for you and your family. Your heat pump would be running almost continuously to heat the outside air and raise the pool temperature, but it would maintain a continuous even flow of warm water into your pool so you don’t have to plan ahead every time you want to swim. Using a gas fired pool heater in this manner would get very expensive very fast. Because of this we now often install electric heat pumps over gas heaters for our new in-ground pool customers as these families anticipate lots of use of their new pool installation. Even though the electric heat pump is more expensive up front its value increases the more you use your pool.

[message type=”info”]Looking for more pool energy savings? Read our article: Variable speed pool pumps help heat your pool more efficiently[/message]

You may have noticed I did not talk about solar pool heaters in this article. At present I do not believe there is a reliable and cost effective solar heating solution available for pool owners here in New England. I suspect in years to come the technology will become more efficient and less expensive and could be a viable option for pool owners, but the technology is just not there yet in my opinion.

As with many in-ground pool options there is no better or worse here, it is all relative to how you use your pool. Take some time to think about your pool usage and decide what fits your needs best. Do you just need a fast acting gas pool heater to use on the weekends and want to extend your pool season into the cooler spring and fall months? Or do you just want to maintain temperature continuously throughout the pool season and opt for the cheaper operating costs of the electric heat pump?

We get asked these questions a lot at Precision Pool Construction and I hope this quick guide helped answer some of them for you.

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  1. deborah shor
    April 28, 2010 at 7:09 am · Reply

    On a daily bases how much would it cost to run the electrical unit on a 20X40 inground pool? Also what size unit would you recommend for the size of the pool and also do you know approximately how much a unit to support the heating would cost?

    Thank you

    • admin
      April 28, 2010 at 9:02 am · Reply

      Hi Deborah,

      It will vary based on your kilowatt hour costs, but in the
      New England area you are at about $6/day to maintain 80 degree water temp. You can drastically lower that cost however with a solar cover that will reduce the night time evaporation.

      I would recommend a heat pump at about 120,000BTU+ for that pool as you have about 30,000gals of water.

      Something like the Hayward HeatPro has a 140,000btu unit that would work well for your size pool. That unit is around $5,000.

      thanks for reading and for your question I’m glad i could help.


  2. Sam
    May 24, 2011 at 7:46 am · Reply

    I have an inground pool which is 35k gals of water. We use it two or three times a week after 4PM in NJ or mostly on demand. It seems the gas heater is the best option based on the above.
    1. Can you advise what would it cost me to operate a gas heater.
    2. can you recommend a system.
    3. To get to 80F, when should I turn on the heater, in the AM or couple of hours before usage?
    4. Do I need a solar cover based on mentioned usage?

    Thanks much.

    • admin
      May 24, 2011 at 9:42 am · Reply

      Hi Sam,

      Thanks for checking out the blog.

      Generally when you are talking cost for a gas heater you also take into account extending your swim season about a month on either end. If we go with that assumption and add in the 35K gallonage I would guess around $600-800 worth of propane or gas. Now if like you say you are just using in season to heat up a few days a week you are most likely going to be a little less than that.

      For your size pool I would highly recommend the Sta-Rite Max-E-Therm 400k BTU gas heater. It is one of the most efficient running gas units and 400K will service that pool best.

      I would be turning the heater on in the morning for use in the afternoonit is around 2 degrees an hour with that unit and obviously depends on startng temperature, which is where a solar cover would come in.

      If you put the solar cover on every night it will trap some of the heat and evaporation that you have gained during the day from the sun and from the pool heater. This way you can ol don to some of that heat to the next day and use less gas and less time to heat it up next time. I would highly recommend a solar and reel system or at the very least a liquid solar fish or solar pill.

      Thanks again,

      -Jay Broyer
      Precision Pool

  3. Sam
    May 24, 2011 at 11:45 am · Reply

    Thanks Jay for a quick response.

    Is the operating cost per season or month?

    I heard when using a solar cover, it would increase the algae level. Is this true? If so, does it mean I would need to increase the chemical in the pool? I am trying to determine if the cover cost and the work needed to cover every night worth the investment.

    What is the percentage of saving when using the solar cover.

    I truly appreciate your input.

  4. Chris Schleede
    July 20, 2011 at 11:05 am · Reply

    Thanks for all of the info that you provide. I am in upstate NY, Albany area and have a 8K gal fiberglass inground pool. We want to use the pool at both end of the season more but do not average more than a 2-3days a week. I have an oversized filter and only need to run it a few hours a day to maintian excellent water quality. So using a cover and not running a filter 24/7 which appears to be needed for a heat pump, it seems to me that a small natural gas heater is the way to go. Would you agree and what would be an appropriate sze?


    • admin
      July 20, 2011 at 11:48 am · Reply

      Hi Chris thanks for stopping by!

      Yes I would recommend a gas heater for your needs. this will allow you to heat the pool when it is cooler in spring/fall and also heat up fast (a few hours) when you are actually using the pool a couple days a week.

      I would still look into some sort of cover to help hold the heat that you are gaining in overnight, even if it is just a liquid solar blanked ie: solar fish or solar pill.

      Thanks again,

      -Jay Broyer
      Precision Pool Construction

    • admin
      July 20, 2011 at 1:01 pm · Reply

      Also a 250,000BTU is more than enough for that size pool. You can get smaller but generally those are above ground pool heaters, I wouldn’t go smaller than 200k BTU.


  5. Benay
    November 16, 2011 at 1:12 pm · Reply


    We need a new pool heater…We have had gas in the past, but we are going to be installing solar panels on our roof that will hopefully absorb all of our electric expenses. We were hoping that an electric pool heater would be a good choice, but would like to know the cons. We live an California, it is a smaller kind of kidney shaped pool, maybe 20x12ish…what do you think, and if you agree an electric heater would be good, can you give me ideas on what type to look at?

    Thank you

    • admin
      November 17, 2011 at 10:48 am · Reply

      The hayward heat pro 116k btu electric heater should work fine for that climate. It will hold a steady temp and should only cost about $250-$400 a year.

  6. Steve
    November 19, 2011 at 1:56 pm · Reply

    With the Hayard HP…does the filter have to be running for HP to work? I am in the Boston area, to keep the pool at 80 degress starting mid May…would it have to run 24/7 untill the outside temperature got warmer? Even when its real hot out or pool never gets over 76-78…with an outside temp in the mid 80’s would the HP still need to run alot to maintain a 80 water temp? Pool size 16×36 Thanks!

    • admin
      February 9, 2012 at 12:38 pm · Reply

      Yes the heat exchanger needs flow going through it in order to run or else the pressure switch will switch off the heat pump. With an electric heat pump your best bet is to keep the pool system running as much as possible in order to build and maintain heat.

    • admin
      March 17, 2012 at 10:35 am · Reply

      Hi Steve,

      The heat pumps d tend to run a lot during the cooler months in order to convert that cooler air into warmer water. In order for the heat pump to work you have to pump the pool water through it, and the only way to do that is to run the filter. If you are worried about the electrical costs incurred by running the pool pump that often I would highly recommend a 2 speed or variable speed pool pump as that will allow you to run the pool 24/7 at a fraction of the electrical costs. The Pentair Intelliflo is a great option for that and I intend to really make my customers aware of the benefits of that pump especially those with heat pumps.



  7. eliecer
    December 7, 2011 at 1:02 pm · Reply

    Hi, just buiding a 10 x 100′ pool. intended for trainning and terapy. regular air temp is between 60 and 75º all year long. what to choose, heat pump or gas heater to get water temp at 80º an hour a day 4 times a week?

    • admin
      February 9, 2012 at 12:40 pm · Reply

      The air temp is warm enough to run a heat pump effieciently and maintain a comfortable temperature. However if you are just using it a few times a week the gas heater may be a better option.

    • admin
      March 17, 2012 at 10:45 am · Reply

      In this situation a gas heater would be the wat to go for sure, you want to heat up quick for moderate use

  8. June
    March 4, 2012 at 3:19 pm · Reply

    Dear Jay,
    Thanks for sharing your expertise on pool heaters. . . you’re clearly very knowledgable . We live in Southern New Hampshire and have recently built a gunite pool. The pool is used daily, and is always just a couple of degrees too cold (in my opinion). It’s about 38′ long and kidney shaped (about 27,000 gallons). I was hoping to put a solar system in . . . though in 2010 you sounded pesimistic about the options available. Are there any advancements in this area? If not, what do you think our second best option might be? I’m a little concerned about the noise level of heat pump, but would rather pay more upfront and not have a continued cost of propane. I would love to hear your specific recomendations.
    THanks in advance.

    • admin
      March 10, 2012 at 3:30 pm · Reply

      Hi June,

      Unfortunately solar for the northeast still doesn’t seem like a viable cost effective solution. I was at a pool expo in Dallas in January and stopped by one of the solar exhibits, and although the tech is pretty nice the costs are no realistic for a 4-5 month pool season.

      I would definitely consider the heat pummp option. The noise really is not that bad, and its easy to put up with when you compare how much propane you will be going through with that much use.



  9. frank
    March 10, 2012 at 1:11 pm · Reply

    We are a motel on the west coast of washington state. Average Daytime Highs April to October are 55 to 65 degrees, nighttime goes from 35 – 50 degrees. Pool closed in the winter, but we are thinking about opening it year round, and then, nighttime 30-40ish, daytime 40ish. Especially in July and Auguest the pool will get daily use, from 11am to 8pm, and then we will put a cover on it at nighttime. From what you are saying, it looks like heat pump out of the question in the winter. What about the summer months (april to October)? If the heat pump is so cost effective in the summer, we may have to do both propane and electric. currenttly we have propane already. I’m getting tired of the repairs though. Also, can you give me suggesions/ price on both propane and heatpump, and if I install them myself, will the warranty still be good? Pool is 30000 gallons, 15 x 30, avg depth 7 feet, thanks!

    • admin
      March 10, 2012 at 3:36 pm · Reply

      Hi Frank,

      Thanks for checking out our blog. First I would check your pool measurements as I have never seen a 15 x 30 pool anywhere close to 30,000 gallons. Generally they are more in the 16-18,000 gallon range with an 8ft. deep end, but you could have a funky depth pool too?

      The warranty will still be good if you install them but a licensed gas fitter has to hook up the propane. Have you considered natural gas? If you have access to it the price of gas is a lot better than propane and you can get your heater in either propane or natural. The only problem I see is even with an auto-cover on the pool you are going to paying some serious cash to keep that pool up to temperature and it might not be cost effective unless the pool there is in high demand off season?

      Regarding the heater repair issue, if you get a new gas heater go for one that has a cupro-nickle heat exchanger, that will hold up a lot better the chemical wear. Either way though it is imperative that you keep a close eye on your ph, alkalinity and calcium levels, as high acidic water and calcium build up and can kill heaters fast.

      Thanks again,


  10. frank
    March 11, 2012 at 12:35 pm · Reply

    Hi Jay,thanks for the quick response!! Great pool company!! It is a kidney shaped pool 34′ by 20′, 3 ft on shallow end 5′ in the middle and 8′ on the deep end.

    I must keep it on from May to Septmember at least, I can close it in the winter. So we are looking at a range of 55 to 65 degrees during the day. People swimming in it all of the time June, July, and Aug. So May and Sept I will have to bite the bullet.

    I think I am stuck with propane, since the tank was put in a long time ago, although I can convert to electric.

    So if I am stuck w/propane, should I buy a new propane heater, or consider electric, given all the circumstances. I read in your post the outside air must be 45 degrees, so then, if it is only 55 to 65, is that good enough, or does it become even more efficient if it is warmer outide ?

    • admin
      March 14, 2012 at 12:49 pm · Reply

      No problem Frank!

      The heat pump will work and cost less year round however you are not going to ahve the ability to ‘crank the heat’ if customers ask. Heat pumps do not heat up fast and really are only good for maintaining a constant temp. In the cooler months it may be hard to keep it up at 80 and if it is 70 and you want to crank it up for your customers you won’t be able to with electric.

  11. frank
    March 18, 2012 at 12:14 pm · Reply

    What do you recommend for a propane pool heater, and are any more cost efficient than others (i.e. burn less propane) and are more reliable? Thanks, Frank

    • admin
      March 21, 2012 at 4:52 pm · Reply

      Hi frank sorry for the delay I missed this one. The sta-rite Max-e-therm by far. efficient, small profile, heats up fast.

  12. Victor
    July 28, 2012 at 9:31 pm · Reply

    Hi Jay, I have been reading your answers and I am impressed with your knowledge. I have an 8 shape pool 34 at one end and 18ft at the other end. It is 22,000 Gallons. 8 1/2 ft at the deep end and 3 ft at the shaloow end. I live in Sacramento, CA and the temperture here is pretty good from May thru October.
    I was considering solar, but I don’t like the panels on my roof, so I am thinking of a heat pump instead. My pool temperture is usually above 70 degrees and I want it 80-82 degrees. What do you recommend?

  13. Victor Musallam
    July 28, 2012 at 9:42 pm · Reply

    Hi Jay,
    I have an peanut shape pool 84 by 18 ft. 22,000 gallons. 8 1/2 deep and 3 ft at the shaloow end.I live in Sacramento, CA and the water temperture from May to October is usually above 70 defrees. I need to get it up to 80-82 degreesfrom May to September. My grandchildre are in the pool daily for couple of hours. I was thinking of a solar panels but I am not to keen on this idea any more. I am considering a heat pump. What do you think is my best bet and what do you recommend if heat pump is correct for my needs.


    • admin
      August 13, 2012 at 3:28 pm · Reply

      Thanks for stopping by Victor, I apologize for the delay as this time of year is very busy for us. However I think you are right on with the heat pump idea. The cost to rum is manageable and it should easily be able to hold 80-82 during the peak season no problem. The new pentair ultra temps are what we are using now, the 120k btu i think is what they put out and it is a beast! It takes up a lot of space so you need to make sure you have some room but the unit runs great.

  14. Meri
    August 30, 2012 at 4:09 pm · Reply

    Hi Jay,
    I have a 20×40 grecian. We are in New Jersey. The water temp in the summer is usually in the high 70’s. would like it to be in mid 80’s. We are considering the Raypac 406A natural gas heater. They have two models one has copper fin tubes(standard) and the upgrade has cupro-nickel fin tubes. Does it make sense to go for the upgrade?

  15. Carson Asperheim
    March 9, 2013 at 5:10 pm · Reply

    When did solar panels start to become popular? Like when did you start to see solar panels on houses and solar garden lights?

    • admin
      March 25, 2013 at 6:09 pm · Reply

      WE do not see a lot of solar in this part of the country, however over the past 10 years especially after Title 20 California is littered (pardon the pun) with solar heated pools.

  16. David
    March 14, 2013 at 12:13 am · Reply

    Hi Jay,
    I live in Louisiana. Summer months are 90s and humid. No heater needed. Fall/Spring temps are 50s to 70 and Winter is 50s to as low as high 30s but usually not lower than 40 even at night.
    I am installing a 580 square foot pool and 8 foot diameter hot tub.
    I am not sure how often I will use the pool in the winter but I’d love to have the option to take a quick swim before I go to work or at night even in the winter months. And would always want the option to use the hot-tub year round. Is natural gas heater the only way to go for me? What might I expect the monthly operatin costs to be in the winter months?


    • admin
      March 25, 2013 at 6:11 pm · Reply

      Hi David,

      Sorry for the delay, I have been away.

      Ya your best best is a gas heater. The heat pump just wont work effectively below about 50 degrees.

      If you try to run that gas heater all winter you will pay for it! Expect gas bills in the $400 range.


  17. Courtney
    April 22, 2013 at 7:45 pm · Reply

    Hi Jay,

    Great article! We live in the Boston area and are looking to add either an electric or gas heater to our 20×40 inground pool. We tend to use it primarily on weekends so gas seems to be the better option, but all our current pool equipment is next to the house so I’m not crazy about adding the gas heater and propane tank making the area even more cluttered looking so I’m leaning towards electric.

    If we opted for the electric heater, do we have to run it all week or would we be able to turn it on around Thursday so the pool is ready for the weekend?


  18. Don
    May 5, 2013 at 1:21 am · Reply

    We live in California and are having 48 solar panels installed in a few weeks as well as a brand new variable speed Pentair Intelliflo for our 35,000 gallon pool. We will be swimming a few times a week from April through September and would like to extend the swimming season. We already have a 110v out next to our pool pump, but would have to run a gas line if we went that way. We would like to keep the temperature around 82-84 degrees. Should be go with a gas heater or electric heater and which model would you recommend?
    Thanks, Don

  19. Ed
    August 21, 2013 at 11:08 am · Reply

    We live in Northern California and have a large in ground pool with a cover. It seems to stay in the mid 70’s during the warmer months so far, but ideally we would like to keep it at 80+ year round. I was considering a solar heater system, but then thought about just doing a solar electric system and using an electric heater for the pool as it seems the solar electric would be able to absorb the pool heating cost easily and still lower our electric bill. After a bit of research I found electric heat pumps as well as standard electric heaters. The standard electric heaters seem to be much cheaper, heat up much faster, and are able to operate in colder weather. Some seem to also advertise very high efficiency. I cannot, however find much information on them as most sites compare only heat pumps and has heaters.

    What is your take on electric heaters (not heat pumps), what kind of operating costs are generally associated as how do they compare to heat pumps as well as gas heaters (we have a gas heater for the spa)?

    • admin
      September 11, 2013 at 12:35 pm · Reply

      We don’t really have straight up electric pool heaters in this area of the country, only gas and heat pumps so I would not be able to comment much on their effiency.

  20. Joe
    February 13, 2014 at 8:48 pm · Reply

    I have a 15 x 30 around 15000 gal and I live in south florida. I am just looking raise the temp
    6 or 7 degrees a couple of times a week in the afternoon in may/june and sept/oct. We use solar discs to maintain the temp. Would you recomend gas or electric and if gas, approximately what size lp tank should I get? Thanks for your response.

  21. giulio
    September 2, 2014 at 11:58 pm · Reply


    We live in NJ and have pool solar heat panels for our 35k pool. Temp usually maintains between 78-88 degrees. If going thru weeks of colder or cloudy weather pool gets colder. Would you recommend a propane gas heater or electric heater to supplement the solar to maintain around 88-90 and Which model would you recommend?

  22. Scott Pierson
    September 6, 2014 at 9:58 am · Reply

    Hi, Jay…We have a 30K gal in-ground pool with spa with a 400 BTU propane heater that works fine for the spa. We live in Austin, Tx and the June –Sept average temp is 80-85 or higher so the pool water temp is fine during these 4 months. The two months on either side of the summer have an average temp in the 70-75 range. I have experimented with using our propane heater to try and maintain 80-85 in the pool during these months and it is way too expensive to do realistically. So I am thinking it would be reasonable to add an electric heat pump to use during the April, May, Oct, Nov months to get things up to the 80-85 level and double our swimming season to 8 months a year. Specifically either the Hayward Heat Pro 125K or the Pentair UltraTemp 120K unit. That would mean having two heaters. I don’t see any discussion out there about using both a gas and electric heater in the same pool. Is there something bad about this idea? If not, how would you best plumb the two heaters?

    • admin
      September 6, 2014 at 10:04 am · Reply

      You can certainly have a combo system like the Scott. WE don’t really see that up here in the northeast as we are not a year round climate however in your area this is definitely something that is done. With the temps you have on the shoulder seasons a 125k btu Pentair Ultra Temp will keep up with that no problem at fraction of the cost of propane.

  23. John
    August 11, 2015 at 11:40 am · Reply

    I am building an indoor pool in Central Illinois. 30′ X 50′ block building with a 18X36 pool. What do you recommend to heat the pool? Gas or Electric? Size?

    • admin
      August 12, 2015 at 3:24 pm · Reply

      Eaither would be fine but if you do gas inside you need to vent it. Electric heat pump has to be outside

  24. Alan
    February 10, 2016 at 1:46 pm · Reply

    our Florida condo requires the pool (and spa) heaters be turned off whenever the daily temperature will not be 60 or above … the pool is maintained at 86. We only have 2-3 day occasions when daytime isn’t above 60 but when the heat is turned off, it takes a few more days to bring the temp back up to 86, Wouldn’t it be more efficient (and less costly) to maintain the temp versus turning it off? Which way uses mmore natural gas — maintaining the temp or recovering the temp?

    • admin
      February 10, 2016 at 4:39 pm · Reply

      Hi Alan,

      It is not an efficiency thing, it is that the compressors just won’t work at all below a certain temperature. Some heaters turn themselves off once it hits 55.


  25. Gary
    September 24, 2016 at 11:13 pm · Reply

    Why is there no talk about liquid heat blanket? In Texas with a heatpump and the liquid blanket the cost for electric is about $1 dollar a day. By Aquacal the best pumps on the market

    G wood

    • admin
      September 28, 2016 at 2:42 pm · Reply

      Hi Gary,

      I sell a TON of liquid solar blankets here in MA and NH. It is a great product. I am not a fan of physical solar blankets , very cumbersome and can be dangerous with children. Liquid solar pills, fish, or the direct additives, are safe, east to use and effective.

      100% recommended whether you have a heater or not!

  26. Henry Killingsworth
    February 28, 2020 at 1:59 pm · Reply

    I thought it was interesting when you explained that one of the benefits of a gas-powered pool heater is that you only need to run it when you are swimming. If I was in this situation, I would probably want to consult with a contractor so that I could get the right kind of heater. I wouldn’t want to have the wrong equipment running my pool.

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