How to Select an Above Ground Pool Heater

Written by:  Danny Rhodehamel
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 (3.96 OUT OF 5 STARS ON 11 RATINGS)

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.

Tips & Warnings

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.

Comments (1 to 15 of 15)

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User: Inyopools

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.

User: Mark

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

User: 

Information was very helpful. Thank you for your knowledge.

User: 

This information is so incredibly helpful! Glad I found it .. I have been trying to figure this out for 2 weeks! Thanks for taking the time to post this.

User: 

Incredibly heplful Thank you!!!!!

User: Dott62

This info is so helpful, thank you! Now I know where to start on my heater hunt. I will be checking out your site for sure!

User: Inyopools

LRC - Most people use something like a Jandy diverter valve to control the water flow between the pool and spa. To do this "automatically", you would have to add a value actuator on top of the valve and wire it to a control box. See our guide on "How To Set Up In Ground Pool Equipment - Part 1 - Circulation" - Steps 9, 10 and 17 for examples. An Electric heater is an option and could be tied into the spa piping but it has a higher operational cost.

User: LRC

Question: I have a High Energy heater that theoretically can heat either a pool or spa. I say in theory, because I cannot find a good diverter valve that could automatically divert to either the pool or the spa. Is there in the market a reputable device that could achieve this. If no, what are the options without having to go the route of two heaters for stand alone purposes. Is electric heater pumps an option?

User: Inyopools

stacy - These heater are run with either natural gas (NG) or propane gas (LP). NG is usually piped to the house by the city/county. LP is generally supplied from a large tank that the owner has to install.

User: stacy

This may sound dumb...but to use the Hayward H series above ground heater, I had to have access to gas on my property??????? or is it a self-contained system?

User: Bette

Thank you for the complete look at heating options for the above ground pool. I hope I made the right decision as I weighed two different configurations of solar heating for supplemental heat on our pool. I've marked you as a favorite so I can buy supplies from knowledgeable people!

User: Foxwood27

This is the best collection of info on above ground heaters. Thank you for compiling it. I will certainly try and make my purchase through your site.

User: 

Thanks for the great information. I learned a lot and am going to do a lot more checking before I purchase.

User: mo

thanks for a the great dissemination of information - i learned a lot - if i decide to buy a heat pump, i'll probably order it from your company

User: Bobcat

I have been in the market. Thanks for the information. I will be buying my Pool Heater from you guys.

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Inyo Pool Products is not responsible for any injury or damaged equipment
while using our guides. Using our guides is doing so at your own risk.
These guides are suggested use of your pool or spa equipment and may vary
depending on which product you are using.