How to Select an Above Ground Pool Heater


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With a pool heater, you can get more use out of your above ground pool by delaying that inevitable closing and opening the pool earlier in the spring. In colder climates, a heater can extend the pool season by a good couple of months and in warmer parts of the US, using a heater can make it possible to keep your pool open at a comfortable temperature all year round. Here we’ll discuss various options for making above ground pools less cool.

Step by Step


Step 1

Above ground pool heaters are rated by BTU’s and a BTU is a basic measure of heat energy. One BTU is the amount of energy required to heat one pound of water one degree Fahrenheit. Heaters specifically marketed for above ground pools have a lower BTU rating than those for in-ground pools. This is because most above ground pools are smaller and therefore have less water to heat.

Step 2

Three common brands for above ground pool heaters are Hayward, Raypak and Pentair. All three offer compact heaters with a small footprint, making them easy to install in almost any area. The Hayward H100ID and the Pentair Minimax are both 100,000 BTU while the Raypak is a little higher at 130,000 BTU.

Step 3

Heating times will vary a bit from heater to heater but using Hayward’s H100 model as an example, you can expect the following temperature rise in an 8-hour time period: Pool Size Gallons Average Temperature Rise 15’ Round 5,300 15.2 18’ Round 7,600 10.4 12’ x 24’ Rectangle 8,600 9.6 21’ Round 10,000 8.0 24’ Round 13,500 5.6 27’ Round 17,000 4.8

Step 4

If you want to heat it faster, you can use a heater with a higher BTU rating. These are usually considered in-ground pool heaters but they will also work for above ground pools. The in-ground models typically range from 150,000 to 400,000 BTU. It is worth noting that a higher BTU heater will take less time to heat the pool which means you’ll use less gas. Of course the higher the BTU, the higher the price of the heater. An in-ground pool heater can easily cost twice the price of an above ground model. So you have to take all factors into account when deciding which heater is right for you.

Step 5

To calculate how much it will cost to operate a pool heater, first you’ll need to determine how often you’ll be using it. Once you have an estimate on the number of hours, you can calculate the cost based on the gas prices in your local area. Propane is priced per gallon and you can contact a propane supplier to find out the current pricing. Natural gas is measured in therms and the gas supplier in your area will have a rate per therm. Either a propane or natural gas supplier should be able to help you figure out how much gas would be necessary to run your pool heater. The heater manufacturers can also help with this if you contact their technical support.

Step 6

If you are concerned about the price of gas and how expensive it might be to heat your pool, you are not alone. While gas heaters for above ground pools are relatively inexpensive to purchase (typically under $1,000.00), the cost of running one is subject to unpredictable factors such as gas prices and weather (lower than expected temperatures may mean you’ll need to run it more). With that in mind, you might want to consider some other pool heating options.

Step 7

An alternative to gas heaters, heat pumps run on electricity and use the outside air to heat your pool or spa. Heat pumps move heat from the air and transfer it to the water in your pool or spa using a refrigeration cycle exactly like a refrigerator or air conditioner. They heat more slowly than a gas heater but cost much less to operate so over time, their higher initial price tag is offset by lower energy expenses. Depending on energy costs, a heat pump can save you up to 80% over propane gas and 50% - 70% over natural gas. This is the main benefit to choosing a heat pump over a gas heater. Another consideration is safety - some pool owners prefer not to deal with combustible natural gas or propane heat. Inyo Pools carries the Aqua Pro PRO600 which is a smaller, 60,000 BTU heat pump designed especially for above ground pools and smaller in-ground pools.

Step 8

Because heat pumps rely on the outside air, they become ineffective once the temperature drops to around 40 degrees or lower. For this reason, heat pumps are much more popular in warmer southern climates but pool owners in the north also use them during the spring, summer and early fall if weather permits. Used in conjunction with a solar blanket, a heat pump is much more effective and most manufacturers recommend retaining heat by covering the pool when not in use. This leads us right into our next option for warmer pool water.

Step 9

Solar blankets or covers are made of a plastic material that is similar to bubble wrap and are designed to retain heat from the sun, a heater or both. They also shield your pool from cool winds and lower nighttime air temperatures which draw away heat. Solar covers float on the surface of the water when the pool is not in use. They come in blue and clear materials, the blue being thinner and less expensive. The clear solar blankets are preferred because they’re not only thicker but also allow more sunlight to pass through the material. This helps to increase your pool temperature as well as prevent the loss of accumulated heat. Many manufacturers of heaters and heat pumps recommend the use of a solar cover for more efficient heating. You can definitely decrease the expense of running a heater by using it in conjunction with a solar cover. If you are in a warm climate with a pool that gets a lot of sun exposure, you might want to try using a solar blanket first, without a heater. It might retain enough heat to keep your pool at a temperature comfortable to you. But if it doesn’t, you can still use the blanket along with a heater for increased efficiency.

Step 10

Solar covers come in a number of common round or oval sizes for above ground pools. The installation of a solar cover is fairly simple since it just needs to rest bubble side down on the surface of the water and does not have to be attached to the deck or pool wall. But since these covers can be cumbersome and difficult to move when wet, many pool owners employ solar reels. The reel is a long tube attached to a base with a hand crank that is used to easily roll up the solar blanket and store it out of the way when the pool is in use. Aboveground pool solar reels attach to the top rail of the pool wall and are designed to swing to the side when you want to use the pool. Another option for temporary storage of a solar blanket is a handy product called the Solar Saddle. Instead of a reel, the Solar Saddle consists of five mounting brackets that attach to the top rail of the pool. When you want to uncover and use the pool, you simply fold up the solar blanket and roll it over the top rail to rest in the brackets.

Step 11

With all of the attention on using renewable resources these days, you may want to go green by installing a solar heating system and getting free heat from the sun. This is better for the environment and your wallet. The initial investment for solar equipment ranges from about $200.00 to $800.00 for most above ground pools. Add to that the cost of installation, if you’re not a do-it-yourselfer. After that, there’s relatively little expense involved with this method of pool heating. You may find you need to repair or replace a panel or connecting parts in the future. But, aside from your pool pump, there are no issues with equipment and you don’t have to worry about gas lines, electrical connections, or corrosion of equipment as could happen with gas heaters and heat pumps. The main drawback of solar heaters is that they are entirely dependent upon the available heat from the sun. You can’t generate more heat the way you could simply by running a gas or electric heater longer.

Step 12

Panels are typically either 2’ x 20’ or 4’ x 20’, depending on the system. Economy systems have the smaller panel size and are used mainly for supplemental heating. Deluxe solar systems have larger size panels which offer complete pool heating. The other main difference between economy and deluxe solar systems is the header size. The header is the opening the water passes through. The larger 2 inch headers on a deluxe panel are considered better as these do not slow down pool circulation and insure better heat transfer to the water. Smaller 1-1/2” headers which are found on economy panels are not as efficient and can reduce water circulation in your pool.

Step 13

Solar panels can be mounted on the ground, on a rack, or installed on a nearby roof. They connect to the pool filter with flex hose. Water exits the pool from the return fitting, passing through the pump, into the filter and then through the hose into the panels. As water passes through the panels, which have been absorbing heat from the sun, it is heated and then returns to the pool through an inlet fitting. This cycle will be continuous as long as your pump is running. You can install an optional bypass (or diverter) valve to close off water to the panels. Solar heaters offer another option worth noting. If you find your pool water gets too hot during the summer months, you can run it through your panels at night which will actually cool the water. This gives you the best of both worlds.

Step 14

If you decide to mount your panels on the roof, you will need to make sure your pump will provide enough lift. Typically, a 1 to 1-1/2 horsepower pump will be sufficient for installations up to 30 feet from the pool and one story high. We recommend that you contact the manufacturer of your pool pump before purchasing solar panels and ask their technical support if it will work for your particular installation. To get the maximum benefit from solar panels, they must be positioned to receive as much full sun exposure as possible, keeping in mind that afternoon sun is stronger and therefore better than morning. As with other types of heaters, it is recommended to use a solar blanket along with your panels to retain heat at night or during high wind conditions. Otherwise, you may end up losing much of the heat you’ve gained during the day.


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 Posted: 8/15/2018 

Hello Monica - If your pump is running 24/7, you don't need to worry about a timer for the heater. You can save some money on the electric bill if you add a timer to the pump and wire the heater to the same timer.

 Posted: 7/18/2018 

Hello St Peter - If you are looking to occasionally heat the pool, the best option would be a gas heater. A gas heater will heat the pool much quicker than a heat pump or solar panels. I would recommend something around 250k btus for a 27' pool.

 Posted: 5/17/2018 

Purchased my heater from your company. All set to go, however I thought I would need a timer for the heater. Now I've talked to a pool installer he says all I need to do is use the thermostat to set it at the temp I want it to stay. Is this correct? Thanks:)

 Posted: 5/15/2018 

Hello Michelle - Solar panels are the most energy efficient option. They typically give you around a 10° increase as long as the panels are receiving a lot of sun. The next option would be a heat pump. These work well as long as the ambient temperature is staying above 60°. The heat pumps work like AC units except for that they generate heat from the outside air.

 Posted: 5/15/2018 

I have an 18’ 54” deep above ground pool and I’m looking into a heater for it. I live in southwest Ohio and I could use some guidance on what would be my best option. I’ve looked into a propane heater but I’m worried about it costing to much to run. Any suggestions?

 Posted: 5/12/2018 

I live in Northern Maine, temps avg in the 70s most of the summer with some warmer days in the 80s. I own a 27 ' round 48" deep salt water pool that we would enjoy more if it was warmer. I do have a solar cover to use. I'm looking for advice on what the best form to heat it would be. We would love to use it on weekends and sometimes during the week if we had guests over. Any advice would be greatly appreciated. We really only have second half of June to end of August to use it before we need to close it up for Fall. Thank you.

 Posted: 3/22/2018 

Hello LD - We'd recommend something around 250-300k btu's. As far as the gas line depth, we'd recommend contacting a local gas company (or licensed pool company). They will know the requirements for your line.

 Posted: 3/22/2018 

I have an oval 18x34 above the ground pool. I am seriously thinking of having a gas heater installed. I get moderate to little sun due to excessive trees in my neighbors yard. What BTU would you suggest, and how deep does the gas line have to be underground? thanks

 Posted: 3/21/2018 

Hello TMEd - I'd recommend something around 250k btus for your pool. Something like that would give you between 1° to 1-1/4° F. rise per hour

 Posted: 3/17/2018 

We have a 28' diameter x 54" wall height above ground pool and live in Ohio. I'm wondering what you would recommend for heating enough to extend our pool season to include May and September.

 Posted: 11/2/2017 

Anmonymous (Mohave pool) - Assuming you don't want to go thorough the expense of installing panels on a roof, I would recommend the Sunheater 2' x 20' Solar Heating System. And assuming your 8'x16' pool is 4' deep, your pool contains about 4'000 gallons of water. For your size pool, I'd recommend a Hayward VL Series Sand Filter Systems. It is designed to handle pools up to 11,000 gallons so it will easily handle the extra load of the solar heater.

Anonymous  Posted: 10/27/2017 

we live in the Mohave desert near Needles. We have an 8'xl6' above ground pool. What is the best solar heating set-up for us? What kind of pump should we have?The pool is under a covered porch on the West side of the house but lots of sun in the yard & on the porch roof.

 Posted: 10/13/2017 

Larko - For your size pool, I'd recommend a small size gas heater like a Hayward A/G Pool Heater 100000 BTU LP. If you have natural gas in your area, buy the NG version for lower operational costs. The heater will raise the water temperature in your pool about 15 degrees in an 8 hour period. Also, buy a solar blanket to help keep the heat in when not in use.

 Posted: 10/8/2017 

We have a 16x32 ag pool. Interested in buying heater to extend season. What are your recommendations?

InyoPools Product Specialist  Posted: 9/15/2017 

Framework - In your area, you would be happier with a gas heater rather than a heat pump. Heat pumps are inefficient in the colder climates and switch to electric coils below 40 degrees – electric is very expensive. Also, under good conditions, they take 7 times longer to heat up a pool than gas heaters. It would take you all day to heat the pool than as it got colder, the heat pump would have trouble keeping up. You'd be better off turning the gas heater on for 1-2 hours before you wanted to use it then turning it off when you were done.

 Posted: 9/13/2017 

We have an AG 12x24 oval, we are just north of Detroit, would a heat pump work for us?

InyoPools Product Specialist  Posted: 8/28/2017 

Lewandowski - For your area of the country, I would suggest buying the largest natural gas heater you can afford. In the north, it is the most effective means of extending your pool season. If you don't have natural gas available, you can go to propane, but, at this time, propane will cost more to operate than natural gas.

 Posted: 8/24/2017 

We have an ag 24' pool and live in central ny. We want to extend our swim season at an affordable price. Solar panels look horrible but not really sure which way to go...gas heater, electric heater, heat pump, solar panels....we do use our solar cover daily. Any advice for a limited budget? Thanks!!!!

InyoPools Product Specialist  Posted: 8/11/2017 

Ltuk - A heat pump in Penn would be struggling to add heat to your pool. You would be happier with a medium size natural gas or propane heater. Also buy a pool cover to keep the heat in.

 Posted: 8/9/2017 

I'd like to use a heat pump for my small above ground pool (18 ft round) to maintain more comfortable temps and extend the season. Is a heat pump a practical solution in north western Pennsylvannia.

InyoPools Product Specialist  Posted: 7/13/2017 

Anonymous (heater) -Your pool contains about 5,000 gallons of water. The smallest propane heater we sell is a Hayward A/G Pool Heater 100000 BTU LP. It will raise the pool temperature about 16 degrees in an 8 hour period. I'd also recommend buying a solar cover to help keep the heat in the pool.

Anonymous  Posted: 7/11/2017 

I have a 9×18 rectangular pool, we want a low cost propane heater we live in Wa State, witch one should I get?

InyoPools Product Specialist  Posted: 7/4/2017 

shetony - It depends on your budget and available space. I would get the largest one you can afford to reduce the number of times it has to be filled.

 Posted: 7/3/2017 

what size propone tank will I need for a 7500 gallon above ground round pool?

InyoPools Product Specialist  Posted: 6/19/2017 

Paul - We don't carry the Pentair Minimax 100 heater but we do have a number of other above ground heaters from Pentair, Raypak, and Hayward. Here is a link to our Above Ground Pool Heaters. Raypak and Hayward have 105K BTU and 100K BTU heaters respectively. It is unlikely that you will be able to install any of these without some PVC piping changes. Generally, the location of each port is shown in their diagrams.

 Posted: 6/18/2017 

Hello I have a Laguna 100k natural gas above ground pool heater, it's not working and leaking. Parts needed are expensive, would like to purchase new. What would be a good replacement heater. I'm looking for something I wouldn't have to change the PVC piping for the heater outlet and inlet lines. I saw a Pentair minimax 100, but can't seem to purchase one. Any ideas?

InyoPools Product Specialist  Posted: 6/6/2017 

Katie V - The answer to your first question is to buy the largest heater you can afford. The bigger the unit the faster your pool will heat up. Raypak has one of the largest above ground heaters that is rated at 130 BTUs. Also natural gas is cheaper than propane if you have access to natural gas. And I would run the heater while you are in the pool. They cool off fast.

 Posted: 6/5/2017 

We have a 24' round pool and live in the Chicago Suburbs. What type and size heater is recommended? I was looking at Haywards but some reviews said they didn't last long and customer service wasn't helpful. Also, do you only recommend running the heater before use? We will use our pool on the weekends and 1-2x during the week.Thanks!

InyoPools Product Specialist  Posted: 4/25/2017 

Drew - Here's our link to "above ground pool heaters". Propane heaters are mixed in with the natural gas heaters. All these manufacturers build a good heater. If you're interested in heating the pool quickly, buy the highest BTU rated heater you can afford. And I would go with the Electronic ignition (ELE) rather that the Millivolt ignition (MV). Also, make sure you buy a solar blanket to maintain the pool temperature once it is heated. Here is another link to our guide on "How To Select a Gas Heater For Your Pool or Spa" for more information.

 Posted: 4/24/2017 

I have a 15' round pool. What are your recommendations for natural gas heaters? I have been looking at the Hayward H100ID, and the Raypak 156A, but wondered if you have any others? Thanks for the great site and information.

InyoPools Product Specialist  Posted: 2/13/2017 

mjjorge - The BTU calculation is the same for either an above ground pool or an in-ground pool. There is no downside to buying a larger heat pump. A larger heat pump will heat your pool faster.

 Posted: 2/9/2017 

If I have an aboveground pool 14ft x 26ft, 52" deep, the calculation says I need approx 110000 BTU heat pump to heat from 60F ambient air to 85F pool warmth. Most places state that 70000 BTU is sufficient for any aboveground pool. Is BTU calculation different for aboveground pools? I'm confused. Is there a downside to buying the higher BTU heat pump other than it's more expensive upfront?

InyoPools Product Specialist  Posted: 1/6/2017 

kerrie632 - Your selection of a gas heater depends on how far north you are, how long you want to extend your pool season and altitude. Because you are in Wisconsin, I would get the largest AG NG heater you can get just to extend your season 1 or 2 months. Assuming your altitude is below 5,000 feet, I would recommend the RayPak 156A Digital Control - 150K BTUs - Natural Gas heater.

 Posted: 1/4/2017 

I have a 24'x52" above ground pool. I would like to get a natural gas heater. Which do you recommend? Also I am in Wisconsin if that matters.

 Posted: 5/22/2015 

To the guy who has a 1 HP pump whose solar panels aren't doing the job past 72 degrees. You are on the right track by slowing down the water you will allow it to absorb more heat before returning to the pool. Another solution is to link 2 panels via hose or pvc pipe or get a larger panel. If this is prohibitive in cost you can also go with a PVC ball valve and throttle your flow. Just be sure you have good connections because the higher pressure behind the valve can make a hose either burst or an improperly glued pvc pipe to begin spraying water. I had a 20 foot by 4 foot black solar panel on my roof that was piped with PVC and I had to install bypass valves around the panel due to the water in the pool approaching close to 90 deg. F. And I live in NY on Long Island, not a desert nor southern state! Just be sure to leave the return valve open back to the pool even if you have the bypass open to recirc back to the pool because if isolated, the water can build pressure in the panel and start pooping holes in the plastic, which just ruins your setup. Leaving the return valve open will allow for expansion and alleviate that problem.

InyoPools Product Specialist  Posted: 4/15/2015 

Tracy - There are basically three types of heaters: gas heaters (propane or natural), heat pumps (electric), and electric pumps (electric). Gas heaters and heat pumps are measured by the amount of heat they can generate in an hour (BTUs). Electric pumps are measured by their wattage. The difference between heat pumps and electric pumps is in their design. Heat pumps work like a refrigerator in reverse pulling heat our of the air. They only work above 40 degrees and take time to heat up the water. However, they are much more cost efficient than the pure electric pumps. Electric pumps use resistive heating like a toaster - heated coils. They are generally costly to operate but can be used over a short period of time. If you want to use a purely electric heater, this link shows the options: Electric Spa and Pool Heaters. Buy the larger wattage heater to heat a pool.

 Posted: 4/13/2015 

I'm confused! I thought you said that heat pumps are electric and heaters are gas(propane or natural). But, when I looked into the heat pumps they gave BTU info. I would like a heater that is electric for a 24' round pool. Can I use one that is typically for a spa? I would like to use it to open the open up and not have it freezing. And also, use a bit longer in the fall. I live on the border between NE and IA. Thanks for your help.

InyoPools Product Specialist  Posted: 6/26/2014 

Mark - Not sure slowing down the flow is the answer. At a higher speed the water doesn't get a hot but more water at a lower temperature may should produce the same heat transfer as less water [running slower] at a higher temperature.

 Posted: 6/26/2014 

I just wanted to mention that I have 2 solar panels which are 25' long that is facing direct sunlight and next to my pool, however because I have a 1hp pump the water pushes through the panels to fast and the highest temp I got was 72d,,,,,now I am looking for longer hoses to try and slow down the flow so the sun will have a chance to heat it,,, and hose is not cheap

 Posted: 11/29/2018 

Mark - I coiled ~150 of plastic well pipe on my roof. Gets me 10 deg delta on a sunny day. I also use a separate pump - a $50 sump pump from a hardware store.