How Does A Pool Heater Work?

Pool heaters can be handy if someone wants to enjoy the fun of swimming in the pool throughout all seasons. 

A pool heater works by circulating water from the source into the heater and then back to the pool via a pump. That is the oversimplified version of what generally happens. 

But don’t think that a pool heater will make your pool into a Jacuzzi. It won’t be as fancy. But it will keep your pool water’s temperature at a comfortably warm level so that it feels relaxing while you bathe.

How Does A Pool Heater Work

Variety of Pool Heater

When it comes to pool heaters, there are several options to choose from. Mainly, there are three variants of pool heaters in the market, and they vary slightly in terms of mechanism. 

Solar Heaters

If you want a heater that is energy efficient and eco-friendly, you might opt for a solar pool heater. It has zero operational cost as the sunlight is free of charge. 

This type of system needs a pump and a solar collector, which stores the heat from sunlight. The machine then uses that heat to warm up the circulating water. 

Electric Heaters

Electric heaters are more common in warming up the pool water. It may not be the fastest method, but it gives a consistent result and can keep the water warm for a more extended period. Nevertheless, it requires much more equipment and needs more maintenance. 

Gas Heaters

The primary power source of gas heaters is natural gas. First, the pump circulates running water through its system. The heater runs the water through a filter to get it to the heating unit. 

When the water reaches the heating unit,  it burns the gas to generate heat and then transfers it to the water. And finally, the heater sends the water back into the pool.

How Does A Solar Heater For Pool Work?

A solar heater’s primary components are a solar collector, a pump, a filter, and a control valve. The pump sends the pool water into the solar collector. 

Before going to the collector, the water runs through a filter to remove any dirt, leaves, or other objects. After the water reaches the solar collector, it gets heated by the sunlight, and then it goes back into the pool. 

But if the solar collector’s temperature is the same as the pool water, the valve to control the water flow allows the water to go back to the pool directly, rather than going up to the solar collector on the roof. 

The primary function that a flow control valve serves is to check the temperature of both sides and decide whether to bypass the collector or let the water go through the collector.

How Does An Electric Pool Heater Work?

An electric pool heater or heat pump pulls the water to a heating tank, and the pump then pushes the warm water back to the pool. You can find two variants of heat pumps or electric pool heaters for the pool – one being a water-sourced pool heater and another being an air-sourced electric heater or heat pump.


This type of heat pump works by moving the heat from a separate water source. It contains Freon-filled evaporator coils, and the pool water runs over this coil. 

As the water runs over the coil of the evaporator, the Freon gas becomes heated. The heated Freon gas runs through the compressor, and then it is compressed into hotter Freon gas. 

A condenser contains enough heated gas that produces external heat. Pool water passes over the heated condenser coil and raises the overall temperature. As a result, the heated water re-enters the pool. 


Rather than generating heat, air-source heat pumps use electricity to obtain the temperature from the surrounding air and transfer the heat into the water. 

The air-source heat pumps’ mechanism is almost like water-source heat pumps. Air-source electric heaters are like air conditioners but in reverse.

The heating unit puts liquid refrigerant inside coils, turning liquid into gas when the heat pulled from the air is passed over the coils. It then runs through and then the condenser, which heats the pool water.

How Does A Gas Heater Work?

This kind of heater burns natural gas inside a combustion chamber. Copper coils, which carry the pool water, run into the chamber for combustion. The gas burns and heats the copper coils which carry the pool water. The hot water then cycles back to the pool. Exhaust created by burning the gas leaves the chamber through a flue. 

Which One Is Better?

The main advantage of gas heaters over electric ones is that they can operate independently of air temperature. It also needs less time to warm up the pool than electric heat pumps. 

Whereas electric pool heaters generate noise, a gas pool heater operates quietly. If your home is in an icy climate, gas heaters are a better choice as they can efficiently work in cold temperatures.

An electric heater operates more efficiently than a gas heater. Electricity is easy to get in most parts of the world, which is why people use electric pool heaters more. Also, unlike gas heaters, electric heaters don’t produce harmful byproducts in the exhaust. 

The increasing price of gas has made gas heaters more inefficient than electric heaters. If you live in warmer weather, then an electric heater is more efficient for you.

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Frequently Asked Questions (FAQs)

Why do you need a pool heater?

Ice cold water won’t make you feel refreshed when it’s winter. You don’t want to catch a cold while swimming in the pool. To make the swimming comfortable, you need a pool heater.

Which pool heater has the fastest heating operation?

A gas heater can warm the water up faster than any other type of pool heater as it involves direct heating by burning natural gas.

How efficient is a solar heater for pools?

It is very efficient due to the usage of renewable energy. And it is the most eco-friendly option to warm your pool water.

Which type of pool heater is the cheapest?

Gas heaters are relatively cheaper options among the three types, but they tend to have a shorter lifespan and are not much energy efficient.

Can I run a pool heater all the time?

You can run an electric heater or gas heater all the time if you want. But a solar heater depends on the sunlight and can’t be used at night. Running a pool heater all the time will raise the cost of using it. It will use more electricity or gas, and the bills will be huge.

How hard is it to install a pool heater?

Installing a gas heater is the easiest option than the other two types. Solar heaters are especially tough to install as the solar collector on the roof can cover 50 to 120% of the pool area. If you’re looking to do the work yourself and not sure about your mechanical skills, get a gas heater. But it’s best to get professional help for the installation process.

How do you differentiate between a heat pump and a heater?

Both the pool heater and pool pump run on electricity. The main point to differentiate is that heat pumps will not use any heating mechanism that uses electricity. Instead, it uses the temperature of the air and transfers the heat into the pool water. So, it is not a direct heating mechanism.

Bottom Line

As a pool owner, you don’t want your pool to remain unused. Nothing beats a swim dunk, especially if you have your own pool. To ensure that you can take a dip whenever you want around the year, get a pool heater during the winter seasons. 

Make sure to do your own research before investing in one. Besides, you already have this article as a guideline. After knowing the essentials, you can choose which type of pool heating technique you prefer. Make sure you settle on your needs and then get whichever suits your preference and climate. Happy swimming!

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