Swimming Pool Heaters: Types, Costs, Pros & Cons
Picture this: It’s a beautiful, warm day. The sun is shining, your sparkling pool is open, and you’re ready for a swim.
You dip your toe in the water and jump back in horror.
Despite the warm weather, the water is ice cold.
Most of us have experienced this in our own pools (or in community pools) on days that otherwise seem like the perfect time to swim.
A pool heater is just what you need on deceptively warm days like these, but how much do they cost, which type is right for you, and do you really need one?
As fiberglass pool manufacturers and experienced pool installers, we’ll break down the types of inground pool heaters that you can choose from, how much they cost to buy and run, the pros and cons of having a pool heater, and a few alternatives for those on a tight budget.
Let’s start with the basics.
Swimming Pool Heater Types: Solar, Heat Pump, Gas
While there are a variety of ways to heat your pool, there are three main types of swimming pool heaters:
- Electric heat pump
Each of these works in unique ways and comes with their set of pros and cons. In the following sections, we’ll cover how each pool heater type works, how much it costs on average, and how much it may cost to run.
Note: There are other types of pool heating systems, like wood burning stoves and electric resistance heaters. These aren’t very common in residential inground pools, so for now, we’re going to stick with explaining solar, heat pump, and gas heaters.
Solar Pool Heater
Solar pool heaters use solar panels to heat the pool water. As the solar panels absorb heat and energy from the sun, they can transfer that heat into the pool water through a circulation system. Right off the bat, you can probably guess that you need to live somewhere that gets plenty of sunshine for a solar heater to be effective.
You’ll also need to have an abundance of space, but this is usually not a problem given that solar panels are typically installed on the roof. How much space do you need? The system needs to be at least half the size of the pool’s surface (but they are often more than the full size of the pool), so consider this if you want a solar pool heater and are still in the process of choosing your inground pool design.
Solar Pool Heater Cost
The beauty of a solar heating system is that solar energy is free. Unfortunately, you will also have to pay for the electricity to run the electric pump that circulates the pool’s water through the system.
To give you a ballpark estimate, you might expect to pay an additional $300 to $950 per year to run your solar pool heater (depending on where you live and your utility rates).
Solar Pool Heater Installation
So, how much does it cost to install a solar heating system? You can expect to pay anywhere between $2,500 and $9,000 and up to install your solar pool heater. Remember, you’ll need an area of solar panels that spans at least half the surface area of your pool, so it’s not going to be the cheapest option upfront.
Keep in mind that solar panels require permits and inspections before they can be used. They also typically take 1-3 days for the actual installation, though they can take longer for a number of reasons, including:
- Your solar panels are ground mounted
- You need to repair or reinforce your roof first
Solar Pool Heater Pros and Cons
Now that you know how much your solar pool heater might cost, let’s dive into some of the pros and cons of going with this type of pool heater.
- Environmentally friendly
- Relatively inexpensive to run
- Long lifespan (typically 15-20 years)
- Can extend swim season by several weeks
- May be eligible for a solar tax credit
Solar panels largely operate on free heat and energy from the sun, making them environmentally friendly and cheaper to run than other pool heater types. They can last several decades with proper care and maintenance and can potentially extend each swim season by at least a few weeks. Finally, installing a solar heating system may make you eligible for a solar tax credit. This means that as of 2020, you can get 26% of your solar installation costs back in credits on your federal taxes.
Note: The credit will not be offered after 2022.
- Expensive to install
- May take longer to install than other heaters
- Dependent upon the sun
- May heat water slowly
- Uses an area the size of 50% to 120% of the pool's surface
One of the biggest drawbacks of choosing a solar pool heater is the cost. Even with a tax credit, you’ll still be paying thousands of dollars to install one. If your roof needs work or you decide to mount your heating system on the ground, the installation timeline can be extended by several days or even weeks. Solar heaters are also dependent upon sunlight, which means they don’t work well in cloudy weather and they don’t work at night. Solar pool heaters may also take longer to heat the pool water, especially unglazed (cheaper than glazed) solar panels. Finally, your solar pool heater will require a lot of space, particularly if you have a large pool.
Electric Heat Pump
Electric heat pumps for pools work by pulling heat from the air and transferring it into the pool water. This technically makes it a form of solar energy since it depends on the surrounding air temperature to work. Typically, the air temperature should be at least 55 degrees Fahrenheit for the heat pump to effectively heat the pool water.
Note: Some electric heat pumps using newer technology have scroll compressors that heat the pool even with lower outdoor air temperatures.
Electric Heat Pump Cost
Electric heat pumps typically cost around $50 to $100 or more per month to operate, making them one of the most cost-effective pool heating systems available. They’re also known to be energy efficient and make another good choice for environmentally conscientious shoppers.
Electric Heat Pump Installation
Electric heat pumps don’t take very long to install, but they can be on the pricey side. Typically, an electric heat pump can cost between $2,000 and $7,000 and up. However, you’ll save a lot of money long-term with the lower monthly operating costs.
Electric Heat Pump Pros and Cons
Now that you have a rough idea of how electric heat pump pool heaters work and how much they cost, let’s dive deeper into some of the pros and cons of owning one.
- Energy efficient
- More environmentally friendly than gas heaters
- Long lifespan (around 10-20 years)
- Lower monthly costs
- Can extend swim season by several weeks
Because electric heat pumps rely on the warmth of the surrounding air, they are more energy efficient and environmentally friendly than gas heaters. They also have a long lifespan ranging from about 10 to 20 years and guarantee relatively low monthly operating costs. Like other pool heaters, they can extend the swimming season by several weeks to several months, depending on the area.
- Expensive to purchase and install
- May heat the pool slowly
- Typically requires air temperature to be 55 degrees Fahrenheit
In addition to being on the expensive side, electric heat pumps can also take longer to heat the swimming pool than a gas heater would. They also usually require the air temperature to be at least 55 degrees Fahrenheit and don't typically operate effectively in colder weather. This minimum outdoor temperature also dictates how long this type of pool heater can extend your swimming season, depending on where you live.
Gas Pool Heater
A typical gas pool heater burns either natural gas or propane in a combustion chamber. This heats the copper coils that circulate the pool water, warming it as it returns to the pool. Unlike solar pool heaters and heat pumps, they don’t rely on the sunlight or air temperature to operate, which can make them more appealing to people living in colder climates.
Gas Pool Heater Cost
Let’s not sugar coat it: gas pool heaters are expensive to operate. On average, it can cost anywhere from $300 to $500 per month to run. Of course, you don’t have to run your pool heater all swim season, especially when the weather is hot in the peak of summer. When you do run it, however, it will cost more than a solar or heat pump pool heater.
Keep in mind that propane costs twice as much as natural gas and will increase your costs accordingly.
Gas Pool Heater Installation
The good news is that gas pool heaters are relatively inexpensive to install, starting at $1,500. Prices for gas pool heaters can range from $1,500 to $6,000 on average, with larger pools requiring more expensive heaters.
Gas Pool Heater Pros and Cons
Gas pool heaters may not be quite as popular as they once were, but they still come with their set of advantages. Let’s explore the gas pool heater pros and cons in more detail.
- May be inexpensive to purchase
- Doesn’t require sunlight or warm air to operate
- Heats the pool quickly
One of the top benefits of choosing a gas pool heater is the relatively low upfront installation cost. For example, pool owners can save thousands by installing a gas pool heater rather than a solar heater. Gas pool heaters will also operate regardless of air temperature, season, cloud cover, or time of day, making them perfect for cold weather and night swimmers. They also heat the pool quicker than a solar or heat pump heater.
- Less energy efficient
- Not environmentally friendly
- Expensive to run
- Shorter lifespan
Needless to say, a gas pool heater is less energy efficient than a solar heating system, and their fuel emissions make them less environmentally friendly. They also have high operating costs compared to other pool heater types, and they have a much shorter lifespan, lasting only around five years.
What size pool heater do I need?
Pool heaters are sized using BTUs, or British Thermal Units. The more BTUs your heater is rated for, the quicker it can heat your pool. The larger your pool is, the higher the BTU rating should be on your pool heater as well. The thing to keep in mind is the temperature that you’d like to achieve and the amount of time that it will take to achieve it.
As a general rule, your pool heater’s output should be rated for 50,000 BTUs for every 10,000 gallons of water that it holds. For example, if your swimming pool holds 20,000 gallons of water, your heater’s BTU output should be at least 100,000.
Do I Really Need a Pool Heater?
Given the opportunity, we find that most pool shoppers would prefer to have a pool heater installed, but many shy away because of the costs. So, the question we often hear is, do I need a pool heater?
Generally, most people with outdoor pools don’t need a pool heater, especially if they live in an area with high average temperatures. In some northern areas, however, a pool heater is virtually required to make the water comfortable enough for swimming.
Have an indoor swimming pool? A heater is necessary if you are building an indoor pool because you can’t rely on the warmth of the sun to heat the water, and you’ll need to be able to regulate the temperature to control the humidity of the indoor environment.
To help you decide if a pool heater is right for you, here are a few questions to ask yourself:
- Is my pool indoors, or am I planning to close it in?
- Do I prefer to swim in warmer water?
- Will children or older adults be using the pool?
- Do I want to extend my swim season by a few weeks to a few months?
- Can I afford thousands of dollars in upfront costs and hundreds in monthly or yearly costs?
If you answered “yes” to all or most of these, you might want to explore your options and start shopping around for a pool heater.
If, however, you wouldn’t mind sometimes swimming in chilly water or closing your pool a bit sooner, you can skip the pool heater and put one in later if you find that your pool is too cold for your liking.
Pool Heater Alternatives
Not ready to get a pool heater but looking for ways to heat your swimming pool? First of all, don’t throw boiling water into your pool. It won’t work, and it can be dangerous. Now that we’ve got that cleared up, here are some safe and effective ways to raise the temperature of your pool water.
How to Warm Up Your Pool Water
- Make sure your pool gets plenty of sunshine. Try removing trees and any plants or structures that cast too much shade over your pool.
- Try using a solar cover. Covering your pool with a solar pool cover will help absorb the warmth of the sun and prevent heat from escaping.
- Use solar rings. If you don’t want to get a solar cover, you can place solar rings over the top of the pool to help absorb some warmth into the water.
- Shield your pool from the wind. Wind can cool your pool water as it blows over the surface, so installing a wind blocker can help if you live in a windy area.
- Try heating mats. These circulate your water through mats warmed by the sun and work best with small-volume pools.
Solar pool cover
Pool Heater FAQ
How hot does the water need to be?
This depends on your preferences and how you will be using the pool. Generally, the pool water should be around a minimum of 75 degrees Fahrenheit to be considered comfortable. However, young children and older adults may require the water to be at least 80 degrees Fahrenheit (26.7 Celsius) to swim comfortably. According to the National Swimming Pool Foundation, the official recommended pool water temperatures are 82 degrees Fahrenheit for recreational swimming and 90-93 degrees Fahrenheit (32.2-33.9 Celsius) for children ages four and younger.
Can I use any pool heater on any pool type?
Yes. Solar pool heaters, heat pumps, and gas heaters will all work with vinyl liner, fiberglass, and concrete swimming pools.
Can I install a pool heater later?
Absolutely! In fact, skipping the heater and installing it later is one easy and common way that people save on upfront costs when buying an inground pool. If you’re interested in getting a pool quickly and on a low budget, here are some more tips on how to get an affordable pool fast.
What causes heat loss in pool water?
According to the National Swimming Pool Foundation, the main reasons your pool water loses heat are evaporation, convection, thermal radiation, and conduction. Water at the surface of the pool is continually turning to water vapor, making evaporation one of the primary causes of heat and energy loss. This is why a pool cover can help to maintain a warmer pool water temperature.
Convection losses occur when heat from the surface of the water dissipates into the surrounding air, and thermal radiation occurs as the pool radiates heat to a cooler sky. Conduction losses occur as the movement of heat through the inground pool's structural components cool down the pool water.
How do I calculate pool volume in gallons?
If you want to size your pool heater and you’re not sure what your pool’s volume is in gallons, an easy way to calculate it is to multiply the length by the width to get the area, then multiply the area by the average depth. Finally, multiply that number by 7.5. Here’s how the formula looks:
Pool volume (gallons) = (LxW) x average depth x 7.5
To get the average depth, you can add the shallowest depth in your pool to the deepest depth and divide that by two. Let’s say your pool is 3 feet at the shallow end and 6 feet at the deep end. Your average depth would be (3+6) ÷ 2 = 4.5 average depth. This formula works best with pools that have a constant slope. If your pool has a hopper bottom or varying depths throughout, you can divide your pool into sections to make calculating the volume easier.
Dividing the pool into sections also works well for freeform and irregular shaped pools.
Have more questions about pool heaters? Leave them for us in the comments and we will answer them as soon as possible!
At River Pools, we manufacture world-class fiberglass swimming pools for customers across North America. If you're interested in getting a fiberglass pool for your home, feel free to browse our catalog of models, try out our pool pricing calculator, or request custom pricing using the button below!