Last Updated: June 29, 2022

What Type of Pool Heater Is Best? Pros, Cons, and Costs

Written By: Pool Care Guide

Gas heaters are the best at rapidly heating your pool. Heat pumps are the most efficient and have reliable longevity. Solar pool heaters have the lowest monthly operating costs and are the most environmentally friendly. Electric heaters are inefficient but are otherwise a middle-ground option.

As you probably can tell, “the best” pool heater will ultimately be determined by what you value most. Before we talk about each type of pool heater, you might want to take a look at this chart. It’s a quick breakdown that covers a significant portion of what we will discuss throughout this article.

Pool Heaters Comparison

Heater FeaturesHeat PumpGasSolar HeaterElectric
Purchase Price$2,000 to $5,000$1,000 to $4,000$400 to $3,000$750 to $3,500
Installation Cost$400$250 to $400$100 to $2,000$400 to $750
Operating Cost
(Excluding Pool Pump Costs)
$25 to $200
(Per Month)
$200 to $600
(Per Month)
$0
(Per Month)
$200 to $500
(Per Month)
Heating SpeedSlowFastSlowFast
Energy EfficiencyHigh (6)Low (1)N/ALow (1)
Lifespan20+ Years5 to 10 Years20 to 30 Years5 to 10 Years

Solar Pool Heater

Positives

  • Lowest operating cost
  • Environmentally friendly
  • Longest lifespan of all heaters

Negatives

  • Slowest to heat the pool
  • Ineffective on cloudy days - not useful in wintery weather

Solar Pool Heaters Are Not Solar Powered Pool Heaters

We don’t want to confuse anyone, so we need to make a quick distinction between two easily confused forms of solar-based heating. Solar pool heaters are not the same thing as solar-powered pool heaters. 

Solar-powered water heaters use electricity collected from sunlight (electromagnetic radiation), and the electricity is used to power the pool’s water heater. 

Solar water heaters absorb sunlight and directly use that absorbed energy as heat that warms up the pool. Solar pool heaters are very simple, but there are a few components you will need to make it work:

  • Filter - Removes debris and pollutants from the water
  • Flow Control Valve - Controls the flow of water, and it is used to divert some of the water into the solar collector
  • Pump - The heart of the system that pushes the water through the pipework. You might need an auxiliary pump if the current pump cannot handle the increased load.
  • Solar Collector - Where heat is collected and passed into the water.

What is the Solar Collector?

The visible light spectrum is electromagnetic energy. When that light is absorbed, the energy from that light is felt as heat.

The sun will naturally heat up the water in your pool, but the water can only absorb some of the energy from the light. Water has a large heat capacity, but it can use some help absorbing it. Water absorbs the red and green spectrums of light, but it reflects the blue. That’s why we see blue when we look that the water. 

If we increase the range of light the water can absorb, we will also increase how much energy the water absorbs. More energy means more heat. That’s where the solar collector comes into play.

We can increase light absorption and ultimately heat absorption by using the color black. Black absorbs all of the visible light spectra so anything colored black will absorb that light and release it as heat

If we want to take advantage of this, the easy solution would be to paint the pool black. That is certainly an option. However, most prefer a balance of form and function. The uninviting aesthetic of a dark murky pool is usually enough to deter most pool owners from using it.

Solar collectors are usually colored black and face toward the noon-day sun. Those tubes are sometimes placed within a box with a clear glass top. Since the glass is clear, the light can pass right through that glass and be absorbed by the black tubing. However, any heat radiated from the tubing will be trapped within the box. As water runs through that warmed tubing, the colder water absorbs some of the heat before making its way back into the pool.

What Are the Advantages of Solar Pool Heaters?

Might Extend the Swimming Season

As temperatures drop, pools become increasingly expensive to heat. While solar heaters become increasingly ineffective as the temperature drops. While solar pool heaters are less effective in cold weather, keep the pool warm for longer into the colder seasons.

Low Operating Cost

Solar Pool Heaters certainly have the cheapest ongoing costs. Since the heating requires zero power, the only ongoing costs are associated with the pool pump. 

In many cases, a secondary pool pump is not required. However, if you require a second pool pump, you can use the chart below to get an idea of how much heating your pool will cost annually.

At the time of this article, the national average cost for electricity is $.1331 per kWh. Electricity costs are constantly changing, so adjust your expectations with the current cost.

Peripheral Pump Operating Costs

Peripheral Pump WattageHourly Cost3 to 5 Hours (Peak Hours)5 to 6 Hours(Heavy Sun)12 Hours(Daylight Hours)
180 Watts$.024$26.25 to $43.75$43.75 to $52.50$105.01
370 Watts$.049$53.96 to $89.94$89.94 to $107.92$215.85
550 Watts$.073$80.21 to $133.69$133.69 to $160.43$320.86

Environmentally Friendly

Solar heaters are the most environmentally friendly of the pool heaters. The zero-energy heating that warms your pool requires less electricity and less gas, so the environmental effects can be reduced by 50% or more. 

Longest Lifespan

Since there are no moving parts in solar heaters, they can work for 20 to 30 years before they need to be replaced. Consistent savings for a few decades will put quite a bit of money back into your pocket.

What Are the Disadvantages of Solar Pool Heaters?

It’s not all roses and sunshine. Here’s the negative side of using a solar pool heater.

Slowest to Heat

Energy in, energy out - Other heaters can heat the pool faster because they can pull energy from the electrical grid that they need to heat up the pool. Solar heaters, not having access to that grid, completely rely upon sunlight to warm the water and a pool pump to circulate that water. With that in mind, it isn’t surprising that they heat the pool at a slower rate than the other options.

Solar Pool Heaters Might Need Help to Heat Your Pool

Solar pool heaters are reliant upon heat from the sun. For this reason, solar pool heaters aren’t good for nighttime, cloudy weather, and temperatures below 50°F. If you live in a temperature or colder climate and plan on swimming in your pool throughout the year, you should install another water heater as the primary system.

Gas Pool Heater

Positives

  • Rapid heating
  • Low installation costs
  • Effective in all weather conditions

Negatives

  • High operating costs
  • Not energy efficient
  • Lower lifespan than other heaters
  • Not environmentally friendly (emissions)

How Do Gas Heaters Work?

A pool heater will not function without a running pool pump. The pool pump pulls water out of the pool and pushes it through a filter, through copper piping inside the water heater, and back into the pool. 

Without running water, an operating water heater would almost instantly overheat and break itself. That’s why there is an internal pressure switch that detects flowing water, and that switch turns off the heater if the pool pump isn’t running.

When the pool pump and heater are set to “on,” a gas burner heats up its combustion chamber, and the heat is passed into copper piping via a heat exchanger. As the pool water travels through the copper piping, the heat is transferred into the water. That water returns to the pool a bit warmer than when it left. 

Propane vs Natural Gas 

There are benefits and disadvantages to each type of gas. Let’s look at how propane and natural gas differ, so you can get a clearer understanding of what a gas pool heater offers versus the other pool heater types.

Natural gas can be sent through a pipeline, but propane needs to be picked up from the store or gas station. On one hand, natural gas is incredibly convenient. On the other, since propane can be delivered anywhere and stored, you can deliver it to a home that’s nowhere near any utility lines. 

Storing propane can be a boon in times of emergency. If the power goes out and the roads are covered in snow, as long as there is propane, propane devices will be unaffected.

Natural gas cannot be stored in most homes because natural gas needs to be stored below the maximum temperature of -177°F (-83°C). That’s pretty cold. The associated cooling costs would be too much for the average household. Propane is much easier to store since it can be stored anywhere between the temperatures of -40°F (-40°C) and 120°F (49°C).

If your location has the pipeline infrastructure necessary to deliver natural gas to your location, that natural gas will likely be your best option. It is much cheaper in almost all situations since propane will cost an average of 2.5 to 3 times more. It’s probably pretty obvious, but most homeowners choose natural gas. 

If you decide upon a gas pool heater, you’ll still need to decide whether to use propane or natural gas. In most cases, pool heaters can use both types. Most of the time, devices that only use one type of gas can be converted to use the other.

Convenience

When it comes to convenience, natural gas is the clear winner. Unlike propane, natural gas lines can send fuel directly to your home appliances. With very little work, you can hook up your gas pool heater to those same lines.

In contrast, propane tanks need to be exchanged or refilled. Fortunately, grocery stores, gas stations, U-hauls, and many other propane exchanges and refill stations are scattered across the map like Starbucks. Unless you live in the wilderness, you are never too far from a propane source. Even if you do live in the wilderness, you can opt to subscribe to a propane delivery service.

Heating Efficiency and Costs

Natural gas is sold in cubic feet while propane is sold in gallons. To produce just over 1,000,000 BTUs of heat, natural gas will require just under 1,000 cubic feet of gas. Currently, the 1,000 cubic feet of natural gas will cost United States homeowners an average of $10.03. 

To produce an equivalent amount of heat, propane will require 11.2 gallons. At the moment, propane costs $2.98. If we times the 11.2 gallons by $2.98, we come to a cost of $33.38

Propane and Natural gas are constantly fluctuating in price, and the location has a significant effect on the cost of these gases. At the moment, the same 1,000 cubic feet of natural gas will cost $25.83 in Hawaii, $16.77 in Florida, and $7.65 in Washington. If you look, you’ll find parallels in propane pricing. Here are links to the current prices of natural gas and propane.

Advantages

Rapid Heating

Gas pool heaters are the best choice if you want to heat your pool as fast as possible. Gas pool heaters provide the most BTUs per buck out of all of the pool heaters.

Purchase Prices That Fit a Range of Budgets

Most of the time, gas heaters are not cheap, but they can range anywhere from  $1,000 to $6,000. 

Effective in All Weather Conditions

Because gas heaters are so effective at heating, they can be used to heat pools throughout the whole year.

Gas heaters are also perfect for extreme weather conditions. Those who live in areas with lots of stormy weather know that windy and snowy weather constantly knocks out power to nearby homes. When power to those homes goes out, the gas-powered stoves still work. If gas powers a pool and hot tub, they will be just as reliable in those extreme weather conditions.

Disadvantages

High Operating Costs

Typically, gas heaters cost significantly more than other heaters. They are usually more expensive to purchase and almost always more expensive to power. You can check out the comparison chart at the top of the page for more details.

Not Energy Efficient

Gas heaters lose much of their heat to radiation. You’re paying for that energy too, and that wasted energy is rather costly. Other heaters naturally generate the heat, or in the case of electrical heaters are extremely efficient.

Lower Lifespan Than Other Heaters

When it comes to heater lifespans, gas heaters and electric heaters are tied in last place with 5 to 10 years. Heat pumps and solar heaters last 20+ years, so they are the clear winners in this regard.

Not Environmentally Friendly

Burning fuels cause emissions that add to the greenhouse gases in the atmosphere. Natural gas isn’t environmentally friendly. However, it is better than propane because natural gas companies cancel out half of the emissions released during production. It isn’t perfect, but it's an improvement over propane.

Heat Pump (Electric Heater)

Air-sourced heat pumps do not generate any heat, which is an uncommon benefit that separates them from most of the other heaters. These heaters offer benefits and disadvantages unique from each other, so let’s spend a little time understanding their differences.

How Heat Pumps Work

Air-sourced heat pumps utilize the heat from the ambient temperature of the air that surrounds them. What is great about these devices is the weather doesn’t need to be particularly warm to heat up the pool. With them, your pool's water temperature can be higher than the temperature of the air around it.

Admittedly, it sounds a bit illogical on its face, but here is how it works.

Assuming we are starting at the same temperature and all other factors are the same, the amount of energy (heat) required to warm one square inch of space to 80 degrees will be less than the amount of energy required to warm an entire room to 80 degrees. If we take the heat energy required to heat a room to 80 degrees and compress the heat energy into one inch of space, that one inch of space would become incredibly hot. 

Air-sourced heat pumps use this trick to warm pools to temperatures higher than the temperature of the air surrounding them. They take the heat from the air by using a refrigerant, they compress that refrigerant and transfer the condensed heat energy into the water.

Advantages

Safer Than other Heaters

Heat pumps do not generate heat. You do not have the same dangers that are associated with gas heaters. There isn’t a fire or a powerful electrical current. These low-energy using heat pumps just use the heat that is already there.

Very Low Maintenance

Heat pumps rarely break down. If there is a problem, it is usually a simple fix. You’ll need to top off some 

Operating Costs Are Low

Because they don’t generate heat, heat pumps also don’t use much electricity. To heat most pools, these heat pumps usually cost between $25 to $200 each month versus the $200 to $600 for gas pool heaters and the $200 to $500 for electric pool heaters.

Environmentally friendly - Reduces carbon emissions

The low-electricity requirements reduce the environmental impact. Recently, this impact was further reduced when freon gas was outlawed. Refrigerants, especially freon gas, are the worst greenhouse gases that can be released into the environment. They are hundreds and sometimes thousands of times more damaging than carbon dioxide. Now, less environmentally harmful refrigerants are used which is a major plus in efforts to reduce greenhouse gas emissions.

Provides Cooling

Many heat pumps can perform their functions in reverse. When they can, we call them reverse cycle heat pumps. When heat pumps work in reverse, they chill the water instead of warming it. You'll be thankful for this feature on the hottest days when a pool would otherwise start to feel like a hot bath.

High Durability

Since heat pumps don’t generate extreme heat, use minimal electricity, and don’t require moving parts, they last a very long time. On average, they last between 20 to 30 years.

Environmentally Friendly

Heat pumps were already environmentally-friendly because the low electricity demands reduced the carbon dioxide emissions used to generate the electricity. Until recent years, these heat pumps contained freon gas. Heat pumps are not perfect containers, so these freon gases would slowly escape over time. Fortunately, today, the refrigerants used in heat pumps are more environmentally friendly.

Disadvantages

High Upfront Costs

Heat pumps cost between $2,000 and $6,500 to purchase and $500 to $1,000 to install. 

Ineffective at Low Temperatures

Heat pumps do not generate heat. They absorb the heat from the air that surrounds them. When there isn’t much heat in the air, the heat pumps become ineffective. When temperatures are below 50°F (10°C), heat pumps become ineffective

A Bit Difficult to Install

Heat pumps might be a bit difficult for a layman to install. It is certainly possible, but you’ll want to study up on the absolute basics of electrical work. You’ll also need to do a small bit of plumbing. However, that part is super easy and is almost as intuitive as playing with a box of legos. 

Positives

  • Safer than other heaters
  • Very low maintenance
  • Operating costs are low
  • Environmentally friendly - Reduces carbon emissions
  • Provides cooling
  • High durability

Negatives

  • Slow to heat the pool
  • Less effective as temperatures drop
  • Ineffective at mid-50s and below

Electric Resistance Heater (Electric Heater)

How Electric Water Heaters Work

There are two types of electric heaters and each of them produces heat in different ways. The first type is heat pumps which we have already discussed. The second type of heater is the electric resistance heater. The electric resistance heater is the type of heater most people refer to when discussing electric heaters.

Electric resistance heaters use a heating element that generates heat by pushing an electrical current through a metallic resistor. At a basic level, whether heat or electricity, all energy is vibration.  When the electrons from the electrical current smash into the atoms of the resistor, the vibrational motion of the current is passed into the metal. As the metal absorbs the vibration, it heats up. That heat warms up the water pipes which pass that heat into the water.

Advantages

Variable purchase prices accommodate most budgets

Electric heaters won’t be the cheapest option, but the prices and capabilities of these units can range enough to fit most budgets and needs.

Medium to fast heating speed

Electric heaters (Not heat pumps) heat pools faster than heat pumps and solar heaters, but they are generally slower than gas heaters. That said, there are units capable of competing with gas heaters, but they will generally be a bit on the pricey side.

Compact Size

Electric pool water heaters are tankless, and that makes them super compact. If you don’t have a lot of space, this could be a great option.

Works in all weather types

Most electric pool water heaters are powerful enough to be used year-round.

Disadvantages

Medium to high operating costs

On average, pool heaters will have an operating cost between $400 to $750. Those costs will change with pool size.

High electricity demand

You’ve probably already realized this point by the name. Relative to the alternative options of heat pumps and solar heaters, electric heaters require lots of electricity.

Low lifespan compared to other heaters

The effective heaters, gas, and electric wear themselves out faster than the less effective heaters, heat pumps, and solar. Gas and electricity are only expected to last between 5 to 10 years. While heat pumps are expected to last 20+ years and solar heaters are expected to last 20 to 30 years.

Positives

  • Variable purchase prices to fit most budgets
  • Medium to fast heating speed
  • Compact size
  • Works in all weather types

Negatives

  • Medium to high operating costs
  • Poor energy efficiency
  • Low lifespan compared to other heaters

Questions and Answers

What is the most efficient type of pool heater?

If you want the most efficient heater, in a warmer climate, a solar heater will give you the most heat for the least amount of cost. If you want the most efficient heater that runs on electricity, you should buy a heat pump.

Which is better, a heat pump or a gas heater for a pool?

The best heater depends on your individual needs. A heat pump can heat your pool cheaper than a gas heater, but it will not work well in cold climates. A gas heater is more expensive to use, but it will allow you to use a pool even if it’s cold outside.

How do I choose a heater for my pool?

Decide features are most important to you. If you prefer to save money, solar heaters and heat pumps are very energy efficient. If you want to heat your pool fast and use it in the winter, a gas heater is probably what you need. If you want a middle-ground option, electric resistance heaters are a good choice.

What is the difference between a heat pump and a pool heater?

A heat pump is a pool heater. That said, what makes heat pumps unique is their method of heating up pools. Most other pool heaters generate their heat by using electric resistance, burning fuel, or warming pipes in the sun. Heat pumps pull the warmth from the air, compress it, and direct it into the water.

How much does it cost to add a heater to a pool?

Heat pumps roughly cost $2,000 to $5,000 to buy, $400 to install, and $25 to $200 to operate. Gas heaters roughly cost $1,000 to $4,000 to buy, $250 to $400 to install, and $200 to $600 to operate. Electric resistance heaters roughly cost $750 to $3,500 to buy, $400 to $750 to install, and $200 to $500 to operate.

Are pool heaters expensive to run?

Solar heaters don’t directly cost anything to warm the water, but they do rely on a running pool pump.On average, heat pumps cost $25 to $200 per month, electric resistance heaters cost $200 to $500 per month, and gas heaters cost $200 to $600 per month.

How much does a gas heater for a pool cost?

On average, solar heaters cost $400 to $3,000, electric resistance heaters cost $750 to $3,500, gas heaters cost $1,000 to $4,000, and heat pumps cost $2,000 to $5,000.

Should I put a heater in my pool?

Most consider the ideal water temperature to be between 78°F and 86°F. Pools take on the temperature of the ambient air. Most places in the United States will require a heater for water to ever reach ideal temperatures. Arizona and Florida will have between 2 to 6 months of ideal temperatures.

How can I heat my pool cheaply?

If you live in an area with a lot of sun, a solar heater can absorb the sunlight and warm the water for the cost of running your pool pump. If you live in a climate that averages in the high 50s or warmer, a heat pump will typically cost $25 to $200 to heat your pool.

Will a pool heat pump work in the winter?

Heat pumps rely on ambient temperature to warm the pool, so it won’t work well at mid-50s and below. Solar heaters require sunlight, so it won’t work well in cloudy weather. Electric resistance and especially gas heaters are great for the colder seasons.

Are propane pool heaters safe?

Propane heaters rarely cause any deaths. That said, there are dangers. Pool heaters need to be ventilated and away from windows to prevent carbon monoxide poisoning. Sometimes ventilation components can be broken or blocked. There is also the possibility of flame rollouts and even explosions.

How warm can a pool heater get a pool?

Your pool’s heating capabilities are effectively only limited by your budget. That said, if we use a normal budget, gas heaters can generally raise temperatures by around 30°F to 40°F. The temperature increase will vary for reasons such as pool size, local weather, and heater BTU capabilities.

What kind of pool heaters are there?

There are solar heaters, electric resistance heaters, gas heaters, and heat pumps.

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