How to Buy The Best Pool Heater

Why do you want to buy a pool heater? Do you hate swimming in a cold pool? Perhaps you just want to extend the pool season so you can swim a little early in April and keep it open until October…or even NOVEMBER!

Whatever your reasons, you’ve found the right guide to buying a pool heater. You’ll learn about the 3 major types of pool heaters including Solar Pool Heaters, Gas Pool Heaters, and Pool Heat Pumps. We’ll dive into how they work, how much they cost, how to find the right size for your pool, the pros and cons of each, and how much money you’ll save each year using a heater with a cover.

Before we begin, the only technical info you need to know is that all pool heaters are sized using BTUs, which stands for British thermal unit. A BTU is the measured amount of heat created by a pool heater. Outputs range from 75,000 Btu to 450,000 Btu. That’s it; that’s really all you need to know. On to the fun stuff!

Let’s start with the most expensive, but most sought after pool heating system.

1. Solar Pool Heaters

Solar pool heaters work by pumping the water from your swimming pool to your filter, and partially diverting it through a group of solar collectors that warms the water before it goes back into the pool.

Solar Pool Heating System

Types of Solar Pool Heaters

  1. Unglazed collectors are heavy-duty rubber or plastic panels with an ultraviolet (UV) light inhibitor.
  2. Glazed collectors are made with copper tubing on an aluminum plate with an iron-tempered glass covering.

Glazed collectors are more expensive, but are more durable than unglazed collectors. However, both include freeze protection to protect against colder weather areas.

Pool Solar Collectors Glazed and Unglazed

How Much Does a Solar Pool Heater Cost?

A solar pool heating system usually costs between $3,000 and $4,000 to buy and install.

How to Find The Right Size Solar Pool Heater

Solar pool heaters require a lot of space in your backyard. The surface area of your solar collector should equal around 75% (more if you keep your pool open year-round — up to 100%).

For example, if you have a 16’x32′ inground swimming pool in the southern United States, you would need a 100% equal surface area. So we multiply 16′ by 32′ to get the square footage of 512. This means you’ll need 512 square feet of solar collectors.

However, if the same size pool is located in the northern United States, which only has the pool open for 6 months out of the year (if you’re lucky), then you would only need about 75% of the surface area equaling 384 square feet of solar collectors.

You’ll need the right size pool pump for a solar heating system. If you’re replacing your current heater with a solar system, you could need a larger pump or a separate pump to help push the water through the solar collectors.



Final Thoughts On Solar Heaters

Before you run out and find an installer, make sure you have enough room in your yard or on your roof for a solar collector. Remember, for large pools, you’ll need a lot of square footage, and the further away the collectors are from your pool, the bigger your extra pump will have to be and the more horsepower you’ll need.

It also depends on the area you live, so make sure you do the math before reaching out to a professional. For more information on how to determine if your property is right for a solar pool heater, follow the section called “Determining the Efficiency of Solar Swimming Pool Heating System” in this article.

2. Gas Pool Heaters

Gas pool heaters use natural gas or propane. Water passes through while a combustion chamber burns and warms the water before returning to the pool. In other words, the water passes through a burning hot tube then back to your pool.

How a Gas Pool Heater Works

Natural Gas or Liquid Propane

The type of fuel you use will depend on the availability and the price of fuel in your area. The good news is both types of heaters are the same price.

If your home has Natural Gas you can also use it to heat your pool. If you don’t, you will have to buy a large, ugly propane tank and install in your backyard, which will need to be filled up regularly. On the other hand, propane is 2 1/2 times more expensive than natural gas, depending on supply and demand.

Millivolt or Electronic Ignition

Millivolt means you have a small amount of gas that keeps a pilot light lit so that it’s always available to fire up while an electronic ignition lights the burners with a spark just like a gas grill.

I recommend going with an electric ignition so you don’t risk a gas leak and you end up using less fuel.

Low NOx vs. Normal Emissions Pool Heaters

A “Low NOx” gas pool heater is designed to release low emissions, which also makes them more efficient than regular pool heaters. This also means your pool will heat faster.

If that wasn’t enough of a sell for Low NOx, they also meet the Nox Emission standards set by the California South Coast Quality Air Management Commission for 2001 and the Texas Natural Resource Conservation Commission Code. So if you live in those two states, you’re gonna need a Low NOx heater anyway.

Other Features

What’s The Average Price of a Gas Pool Heater?

So how much does a pool heater Cost? On average, the cost to run a natural gas pool heater is $300-$600 per month and even more for a propane heater.

New inground gas pool heaters can cost between $1500-$3500, depending on the size, type, and brand.

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How to Find The Right Size Gas Pool Heater

Just like any pool heater, you need to first know the surface area of your pool in square feet. You’ll also need to figure out the average air temperature in your area.

  1. Decide what you roughly want your pool water temperature to be and what the average temperature outside will be during the coldest month.
  2. Subtract the average temperature for the coldest month from the temperature you want your water to be to figure out the temperature rise needed.
  3. Calculate the pool surface area in square feet by multiplying the length and the width of your pool.
  4. Then, use this formula to figure out the BTUs you’ll need your heater to output: Pool Area (Sq. Ft.) x Temperature Rise x 12.

For example, if you own a 16’x32′ inground pool in New Jersey, you can use the US Climate Data website to find the average temperature in your area. The average temperature in NJ during the month of October is 65 degrees Fahrenheit.

If I want the temperature of my pool to be 80 degrees all the time, then my Temperature Rise calculation is:

80 (degrees) – 65 (degrees) = 15 degrees in Temperature Rise.

Using the BTU formula my calculation would be:

512 (pool surface area in square feet) x 15 (Temperature Rise) x 12 = 92,160 BTUs of heat needed to be generated by my new pool heater.



A Quick Note About Gas Lines

Before you buy a gas heater, it’s good to know the distance from the gas meter to where the heater will be installed. Even if you’ve sized the heater correctly, the distance from the meter their gas line size may not support the heater. Simply stated: the heater won’t fire.

By the time you have spent up to $2000 for a heater and then to learn its going to cost $500-1000 to run a new gas line; the additional investment generally ends with frustration.

What land minds to avoid:

Knowing the correct size of the heater to purchase, distance, and gas size beforehand will save time and trouble.

I have to thank Leslie’s Pool Supplies for emailing me about this update. Thanks, guys!

Final Thoughts on Gas Pool Heaters

Gas heaters will get the job done quickly. That’s the reason I like them. I’m a pretty Eco-friendly guy, so I would never buy one. But if you REALLY hate a cold pool and want to extend your pool season, you might want to think about getting one.

I would recommend them if you live up north where outside temperatures are cooler. You can heat the pool up quickly and use a solar cover to maintain the heat so you can cut down on operating costs.

For more info on determining “Efficiency of a Gas Pool Heater,” read this.

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3. Pool Heat Pumps

Water from your pool passes through your heat pump, just like a gas or solar heater. The heat is created by a fan that takes the outside air and directs it over an evaporator coil. There is liquid refrigerant inside the coil that absorbs the heat from the air and turns into a gas.

The warm gas heads over to a compressor which increases the heat, then make its way through a condenser. The condenser is what takes that hot gas and adds it to your pool water.

As the hot gas passes back through the condenser, it transforms back into a liquid and heads back to the evaporator to start the whole process again. Pretty cool, eh?

How a Pool Heat Pump Works

How Much Does a Pool Heat Pump Cost?

Pool heat pumps cost more than gas pool heaters up front, but they cost less to run over the pool season because of their unique heat generating ability. They also last longer than gas heaters, too.

Pool heat pump prices start at $2,000 – $3,000 and go as high as $4,000 – $5,000.

Of course, the cost to run it will depend on where you live. For example, if you live in a warmer climate, it will cost less to run.

Maintaining an outdoor pool in Florida at 80 degrees year-round costs about $1,400 annually, and only $300 if you use a solar cover.

In the Northeast United States, maintaining an outdoor pool at 80 degrees from May to August costs about $1,100 annually and only $120 with a solar cover.

Here is the source of these average pool heat pump prices.

How to Find The Right Size Pool Heat Pump

Just like a gas pool heater, Heat pump pool heaters are rated by Btu output. However, they’re also rated by horsepower (hp). Standard sizes include 3.5 hp/75,000 Btu, 5 hp/100,000 Btu, and 6 hp/125,000 Btu.

To calculate an approximate heater size for an outdoor swimming pool, follow the same steps above for finding a gas pool heater.



Final Thoughts

I really like heat pumps. If you don’t want to invest in a solar pool heater, this is the next best thing to be more environmentally friendly with your pool. Sure, it costs more up front, but you’ll make that back in operating cost savings in about a year or two.

You can also get heat pumps to heat the water in your home. There is a lot of benefits and you can find out more about the cost savings here.

Add a Solar Cover and Digital Thermometer for Efficiency

If you invest in any pool heating system, you must invest in a solar cover or liquid solar cover. In my book, The Art of Pool Care, I mention and illustrate how this can drastically reduce your heating bill.

If you imagine your pool as a giant cup of coffee that is heated up once by your pool heater, then a solar cover would act as the lid to your cup.

A digital thermometer is another good investment so you can keep an eye on your water temperature to help you maintain the heat. It will also help you determine what your preferred water temperature is.

While you may assume 80 degrees is right for you, your digital thermometer might advise otherwise. Which could also save you money when heating your swimming pool.

What is The Best Pool Heater For Your Swimming Pool?

Choosing the perfect pool heater will depend on where you live in the world and what type of heat source is available to your home.

Of course, you can buy any of the three pool heating systems on the market no matter where you live, but this is just a recommendation.

If you’re worried about your budget, I would recommend a pool heat pump with a solar cover all around. It may be a heavy investment up front, but it will pay for itself in the long run. It’s the best economical investment for heating a swimming pool.

That’s it! Wasn’t that easy? If you have any more questions about heating your swimming pool, you can ask them in the comments below or on our Facebook page. I’ve also provided some additional reading if you want to dive a little deeper, but hopefully, this post covered most of it.

Best Swimming Pool Heaters

We have put together a list of some of our favorite pool heaters to help you find the perfect heater for your backyard water playground. These pool heaters range from the most affordable options available to the more expensive options. We believe this list will give you just the right information you need to find the swimming pool heater that is right for you.

1. Hayward H400FDN Universal H-Series

The one heater for anyone with a large pool, the Hayward H400FDN features 400,000 BTU’s of heating power designed to take care of the heating needs of almost any residential pool available today. Designed in much the same way as all Hayward products, you can easily connect to your system to replace an aging Hayward and you will never have to worry about compatibility in the future. The system itself is designed for very low emissions and efficient running so while your heating bills will go up, they will still be lower compared to other heating systems. It features easy to use digital panels to adjust any setting you need quickly so you can heat your pool to just the right temperature that you want.

Hayward H400FDN Universal H-Series 400,000 BTU Pool and Spa Heater Price: $2,700.00 Hayward H400FDN Universal H-Series 400,000 BTU Pool and Spa Heater If you click this link and make a purchase, we earn a commission at no additional cost to you. Last Updated: 09/16/2019

2. Pentair MasterTemp

The Pentair MasterTemp provides you with 40,000 BTU’s of gas heat making it the perfect heater for many inground pools. With no pilot light and fast startup, it will begin heating fast so you can start warming your water for a nice dip when it is starting to get cold outside. It features easy to read indicator lights and a digital display that makes it easy to check on and adjust the settings for the perfect operating temperature. This unit is also one of the quietest on the list, so if noise is an issue for you, this heater is definitely worth a closer look.

Pentair Mastertemp 300K BTU Pool Heater Price: Pentair Mastertemp 300K BTU Pool Heater If you click this link and make a purchase, we earn a commission at no additional cost to you. Last Updated: 09/16/2019

The list above represents some of the best and our favorite swimming pool heaters on the market. But it is by no means the be all end all for swimming pool heaters. There are many options out there for you to choose from. While each of these will do a great job, you need to make sure they are right for your pool before you make your purchase.

Just because the temperatures are getting colder doesn’t mean you have to close your pool for the season. By using a swimming pool heater, you can enjoy your pool and swim comfortably regardless of the temperature outside.

Who says winter can’t be swimming season?

Happy Swimming!

Frustrated by adding chemicals and trying to keep your pool clear all the time?

We cut out all the confusion of pool maintenance in this easy-to-read illustrated ebook and video course. It'll help you save $100 right away on pool care!

Click here to learn more
The Pool Care Handbook


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