9 Ways to Heat a Pool


Considering how popular they are, one might think that electric heat pump pool heaters, electric resistance heaters, and gas pool heaters are the only ways to heat a pool. However, one can heat a pool through many other means, including:

  1. Electric heat pump
  2. Electric resistance pool heater
  3. Gas pool heater
  4. Solar panels
  5. Solar pool cover
  6. Using a solar heater
  7. Black hose
  8. Liquid solar pool cover
  9. Solar rings

One thing to note is that all the heating methods we have mentioned so far do not offer the same pool heating experience.

For one, electric resistance heaters and gas pool heaters offer higher and faster temperature rise than every other method. Heating with solar panels can help you cut down on the electricity/gas costs that come with heating with electric heat pumps, electric resistance heaters, and gas swimming pool heaters.

Solar rings and solar pool covers do not necessarily heat pools. Most of their function comes from retaining heat in a swimming pool that has already been heated. Then black hoses work pretty much like solar water heaters; they absorb solar heat and transfer the heat to the water within them, raising the water temperature.

9 Ways to Heat a Swimming Pool

1. Electric Heat Pump Pool Heater

Electric pool heating pumps draw their heat from the atmosphere. The pump is fitted with a fan that pulls in warm air from the environment. Once inside the pump, the warm air is directed to an evaporator coil, absorbing heat from it and transferring it to a liquid refrigerant.

When heated, the liquid refrigerant gasifies and travels to the compressor. In the electric pool heat pump compressor, the gasified refrigerant gets hotter as it is compressed. Then the compressed gasified refrigerant is transferred to the condenser, where it transfers heat to the pool water and becomes cool. The heated water then returns to the swimming pool, raising the temperature and heating your pool.

Electric heat pumps work effectively at average air temperatures above 45℉. At lower temperatures, you will not get a substantial change in pool temperature.

Compared to solar heaters, which are a close alternative, electric heat pumps are expensive to run. On average, an electric pool heat pump will accrue a monthly running cost of about $100. But a solar heater rarely ever costs you anything to run.

2. Electric Resistance Pool Heater

Unlike an electric heat pump, an electric resistance heater does not absorb heat from surrounding air. Instead, it generates heat from electrical energy. This pool heater creates heat as electricity runs through a heating element (typically a metal resistor).

One of the advantages of electric resistance pool heaters is that, unlike electric heat pumps & solar pool heating options, they do not depend on air temperature or solar energy. They only depend on the availability of electricity. So, even in colder seasons, you can heat your pool with an electric resistance heater.

Beyond extending your swimming pool season, electric resistance heaters can raise the temperature of your pool to higher temperatures within a short time. They are also one of the most compact swimming pool heating options you will come across.

While electric resistance heaters are pretty effective at swimming pool heating, they are not as efficient as electric heating pumps. In other words, an electric resistance heater needs larger amounts of electricity to achieve the same level of heating as an electric pool heat pump.

Apart from not being very efficient, electric resistance heaters attract high operation costs. On average, you may spend as much as $500 per month while using an electric resistance pool heater.

3. Gas Pool Heater

Gas swimming pool heaters are typically fueled using natural gas, but they may also run on propane. They are perhaps the most popular pool heating option.

Gast pool heaters work by generating heat from natural gas or propane combustion and transferring the generated heat to pool water.

As the pool pump drives the water flow through the system, the water passes through the pool filtration system then enters the heater. In the heater, the heat of combustion of the gas is transferred to the water, and the heated water returns to the main water body to heat your pool.

Like electric resistance heaters, a gas heater does not depend on air temperature or the sun for heating. This means you can use this method to heat your pool even in cooler seasons.

But while gas heaters are pretty effective, you best use them for irregular pool heating. Unlike solar pool heating options, gas heaters are expensive to operate, and they do not last long.

4. Solar Panels

In place of electricity from an electrical grid, you can power heat pumps or electrical resistance heaters with solar panels. Doing this will reduce pool heating costs that come with using power from an electrical grid.

Using solar panels as the source of electricity for an electric pool heat pump or an electric resistance heater will certainly reduce running costs. However, the initial cost of installation might be very steep.

To generate the same amount of power needed by an electric pool heat pump or an electric resistance heater, you will need a solar panel with a huge surface area. Of course, the larger the surface area of a solar panel, the more expensive it would be.

5. Using a Solar Pool Cover

Using a Solar Pool CoverUsing solar covers is one of the most common ways to reduce pool heating costs. According to data released by energy.gov, using a solar cover alongside an electric heat pump can reduce pool heating costs by over 80%. A similar estimation applies when you use solar cover alongside gas pool heaters.

While solar covers can heat your pool water to an extent, their primary function when used on pools is heat retention. A solar cover typically preserves the warmth in a warm pool by reducing the rate of evaporation. Once evaporation is reduced, the rate of heat loss will drop. And since solar covers reduce the evaporation rate, you also get to reduce the rate of water loss from your swimming pool.

Besides reducing evaporation rate, solar covers promote heat retention by reflecting escaping heat back into the pool or insulation.

However, beyond heat retention, solar covers can also give you a warm pool by transferring heat from the sun. Solar covers can heat a swimming pool by radiation, conduction, and convection. It all depends on the color of the pool cover.

Solar covers are available in many colors, but clear and blue solar covers are the most common types. When buying a solar cover, you should note the color because the heat retention and pool heating experience of solar covers differ with their colors. For one, clear solar covers heat your pool faster and more efficiently than blue solar covers. However, a blue solar cover will retain heat for longer periods than a clear solar cover, so they offer prolonged heat loss prevention.

A solar cover is not all perfect. Depending on the color of the solar cover you opt for, you may have to spend more on pool chemicals.

6. Using a Solar Pool Heater

Solar pool heaters and electric pool heat pumps are top among the most efficient pool heating options. But compared to each other, a solar heater is the more energy-efficient pool heater.

Solar pool heaters heat a swimming pool in an uncomplicated way. These heaters come as solar collectors (they may also be called solar panels or solar mats). These collectors work alongside pool pumps, and they come with inlet and outlet pipes.

The pool pump facilitates the circulation of water through the whole system. It will pass through a filter before entering the solar collector through the collector’s inlet pipe as the water travels.

As the sun shines on a solar collector, the collector collects and retains solar heat. The retained heat is then transferred to the water circulating through it. Once heated, the water returns to the swimming pool and raises the overall temperature.

This heating cycle continues except the pump is turned off or the sunsets.

As we mentioned earlier, a solar heater is inexpensive to operate compared to an electric heat pump. However, the cost of installing a solar heater is pretty steep compared to that of an electric heat pump pool heater.

7. Black Hose

Black HoseOne factor determining the initial cost of installing a solar heater is the type of solar pool heater one chooses to buy. Of the 4 main types of solar pool heaters, propylene mats are the least inexpensive, and they go for around $500 to $3000, which is still a bit expensive. The good news is, that you can create a DIY solar pool heater for yourself for less.

The main material you need to create your DIY solar pool heater is a black hose. You coil the hose and place in it a black insulated box. Then you create an exit path for the inlet and outlet tubing of the hose. Now, this description simplifies the whole process of creating a solar pool heater with a black hose. But there are a few more steps that you must take to get the best outcome from your project.

8. Liquid Solar Pool Cover

A liquid solar cover works in pretty much the same way as a regular solar cover. It promotes heat retention by reducing heat loss through evaporation.

Liquid solar pool covers are made from fatty alcohol. When added to water, they form an invisibly thin layer at the top. Liquid solar covers remain atop water because they are lighter than water.

Interestingly, the liquid solar cover layer formed on the top of the water is only about 1-molecule thick, yet it is pretty effective. However, to get the full effectiveness of a liquid pool cover, you must regularly add it to your pool.

Beyond being almost imperceptible to swimmers or pool owners, liquid solar pool covers are non-toxic and eco-friendly. So, one can swim with them in the swimming pool without any inconvenience.

The downside to using liquid pool covers is that they can be broken with agitation. So, if your pool is exposed to wind, the liquid seal will break. Also, if you take vigorous strokes while swimming, the seal may break.

You may get a windproof pool enclosure if you live in a windy and would like to use a liquid pool cover.

One advantage liquid pool covers have over regular solar pool covers is the portability. You do not have to struggle to spread a liquid cover over a pool, unlike regular solar pool covers.

9. Solar Rings

Solar RingsSolar rings act pretty much like solar pool covers. They prevent heat loss by reducing the rate of evaporation of the pool.

The primary difference between solar rings and solar covers is their size. While solar pool covers typically cover larger areas, solar rings cover smaller pool areas, and they are easy to move around. This makes them easier to install and use than solar pool covers.

Beyond reducing heat loss, solar rings may also heat the pool the same way solar pool covers do. Solar rings typically come as a bilayer of heavyweight UV-resistant vinyl with a clear upper layer and a blue lower layer.

The clear layer focuses solar energy from the sun to the blue layer, and the blue layer absorbs the energy and converts it to heat. This heat is then transferred to the water below the ring to heat your pool.

Then when night falls and the sun is no longer out, the insulating air in the clear layer keeps the heat in the pool from escaping.

Since solar rings are smaller than solar pool covers, you can use multiple units in one pool. Some rings even come with magnets to facilitate attachment of the rings to each other.

Overall, solar sun rings are pretty effective – in fact, it is estimated that they can generate as much as 21,000 BTUs of heat in a day. Nonetheless, they come with some of the same downsides as solar pool covers.

Do Garbage Bags Really Heat a Swimming Pool?

Garbage BagsIt is quite possible to heat your pool with garbage bags. However, the bags must be of a dark color – preferably black. Brightly colored garbage bags may reflect the heat coming from the sun away from the pool.

When you place them in your pool, black garbage bags will absorb heat from the sun and transfer it to the water at the surface of the pool, raising the pool temperature. But while they can heat your pool in this way, the rate of heating with and without garbage bags on the pool is not very significant.

While garbage bags may not heat your pool significantly, they do help reduce the rate of evaporation. Of course, a lower evaporation rate will come with less heat loss, which will keep your pool warm.

You can even promote heat retention in the pool by filling the garbage bags with air. Since air is an insulator, it will keep heat from escaping.

Will a Black Tarp Heat a Pool?

Just like black garbage bags, a black tarp may heat a pool. However, it may not be much faster or more effective than when direct sunlight heats the pool.

A black tarp will be more useful in retaining heat in your pool since it can also reduce the rate of evaporation of water from the swimming pool.


As you may have seen, somehow, virtually every one of the pool heating options we discussed relies on natural energy for heating. While each one offers different heating efficiency, the best way to heat your pool is to combine a method with high heating efficiency with a method that reduces heat loss. With this combination, you will not have to heat the pool frequently. Consequently, you will be able to cut down on your pool heating costs.

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