How Does a Pool Heater Work?

Say goodbye to cool pools

Boy having fun in the backyard swimming pool
Photo: Belinda Howell / Moment / Getty Images
Boy having fun in the backyard swimming pool
Photo: Belinda Howell / Moment / Getty Images
Highlights
  • Pool heaters work by cycling water from the pool into a heating tank and then pumping the warm water back into the pool. 

  • Heat pumps, electric, gas, and solar are the main types of pool heaters.

  • A pool heater costs an average of $2,940.

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While you don’t need a pool heater, it's a welcome feature for many pool owners. Knowing how to heat a pool can mean the difference between taking full advantage of your personal splash zone and avoiding it when it's chilly. We’ve put together a guide on the ins and outs of pool heaters so you know what you’re getting into.

What Is a Pool Heater?

A pool heater—also known as a heat pump—is what it sounds like. It’s a device that maintains a warmer pool temperature by cycling water from the pool into a heating tank and then pumping the warm water back into the pool. Pool heaters can easily be installed by a pro to a new or existing pool.

How Does a Pool Heater Work?

When it comes to heat pumps—the most common kind of pool heater—the process begins when the water enters the heating tank. The pump uses a fan to draw in heat from the outside air warmed by the sun and circulates it through an evaporator coil. 

Liquid refrigerant within the coil absorbs the heat from the outside air, turning it into gas. The gas then passes through a compressor, increasing its heat. It then passes through a condenser, which transfers the gas heat to the cooler water circulating in the heater before it passes into the pool.

How a pool heater works illustrated, including the fan, evaporator coil, and compressor

Different Types of Pool Heaters and How They Work

Technician checking electric pool heater
Photo: welcomia / iStock / Getty Images Plus / Getty Images

While heat pump pool heaters are what pops into most people’s minds, there are a few other main types of pool heaters that function differently. 

Gas Pool Heaters

Gas pool heaters are powered either by propane or natural gas. They work by burning the gas in a combustion chamber and having the pool water go through another chamber, warming as it passes through.

Solar Pool Heaters

When it comes to solar pool heaters, you’ll need a lot of space and direct sunlight to make them work. With solar pool heaters, the pool water travels through a series of filters and pipes and warms up as it travels through. The warmth itself is generated by the energy accumulated from solar panels.

Electric Pool Heaters

With electric pool heaters, electricity heats a set of resistance coils, consequently warming the pool water that filters through the pool heater. This system avoids propane and gas emissions but can raise your energy bill.

Angi Tip

For most people, a comfortable swimming temperature ranges between 78 to 82 degrees Fahrenheit. If installing a heater, talk to your electrician or pool contractor about how this may impact your electrical bill.

Caroline Gilbert
Director, Content & Editorial, Angi

How Much Does a Pool Heater Cost?

On average, a pool heater costs $2,940, but costs can range from $300 to $5,600. The exact cost of a pool heater depends on factors such as pool size, type of pool heater, and location.

There are also various ongoing costs associated with pool heaters, including increased energy bills, winterization, and maintenance. For example, it costs around $120 to $200 to heat a pool with a heat pump every month. If you have a pool heater, you should also consider the pool heater repair cost should anything happen to it.

Can You Install a Pool Heater On Your Own?

Yes, you can install a pool heater on your own if you already have the necessary hookups. Doing it yourself could save you money, but it’s only smart if you know how to do it properly and safely.

If you don’t already have one and need to lay down a gas line, water line, or electrical circuit, it is best to hire a professional pool heater service near you to help you get the job done. A professional can also guide you in acquiring the necessary permits for installing a pool heater.

Frequently Asked Questions

When you first install a pool heater, it can take anywhere from eight to 48 hours for it to heat up the pool. But on average, it takes around 12 hours. The exact amount of time it takes for a pool heater to heat your pool ultimately depends on the pool’s size and the type of heater you have.

It depends. As long as you’re consistently using it, then leaving it on is best to maintain the temperature. However, if you know you’re not going to use a pool for a couple of days or are going out of town, you should turn off the pool heater to save on energy costs.

Water only runs through a pool heater when not in use if the heater doesn’t have a bypass system. A bypass system stops the flow of water through the heater when not in use. If you don’t have one, then yes, water will still run through the pool heater even when not in use. Not having a bypass system may increase the effects of wear and tear on your pool heater or disrupt the water’s chemical balance.

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