Pros and Cons of Solar Pool Heaters

Rooftop Solar Pool Heating Panel

Are you planning to install or upgrade a pool heating system? If you’re looking to extend your swimming season, adding a heater to your pool is a great option. And an even smarter option is to go solar. But to know if solar is right for you, weigh the pros and cons of solar pool heaters.

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What is a Solar Pool Heater?

Solar pool heaters are devices that use thermal collectors to heat water with sunlight. They are widely used for residential and sometimes commercial pools. A solar pool heater consist of four main parts: 

  • Solar collectors: devices that heat the pool water by the sun.
  • Filter: removes the dirt and debris from the water before it pumps into the collectors.
  • Pump: continuously moves the water from the solar collectors to the pool.
  • Flow control valve: device that controls the flow of the pool water through the solar collector. It can be either automatic or manual.

How Does a Solar Pool Heater Work?

Solar pool heaters are typically mounted on your roof to use the sun’s thermal energy to heat your pool water. The water from your pool is pumped through a filter and up to the solar collectors on your roof.

There are different types of solar collectors, made with different materials, but the three types of solar collectors used for pools are:

  • Flat-plate: Typically mounted on the roof or a rack on the ground, these collectors consist of a large flat sheet of polypropylene or hard plastic. Some flat-plate collectors are available as freestanding units supported by a frame with legs to adjust the angle. The panels are connected to the pool’s pump through plumbing and tubes and heat the water as its pumped through channels that run through each panel.
  • Evacuated tube: This type of collector is a vacuum collector and consists of parallel rows of glass tubes containing a metal heat pipe attached to a fin that absorbs and transfers heat from the sun in a metal collection tube. The heat pipe collector uses a special fluid that evaporates so the steam rises in the individual heat pipes and warms the fluid in the main pipe, generating heat. The vacuum that surrounds the outside of the tubes greatly reduces the risk of heat loss. These types of collectors can be mounted on the ground or the roof.
  • Batch collectors: Batch collectors are composed of a water tank or tubes placed inside an insulated box. Water in the tank or tubes is heated by the sun before returning to the pool. Batch collectors can be mounted on the ground of the roof.

These solar collectors look similar to photovoltaic (PV) panels but include tubes inside so pool water can absorb heat and make the water your desired temperature. The water enters through the bottom of the collectors and as the water gradually rises to the top, it’s heated by the sun with solar energy.

Many solar pool heaters also include flow control valves and automated sensors to detect the temperature of the water. The flow control valve diverts water through the solar collectors, which will heat the water if your pool is too cold. If the pool is too hot, the control valves stop more hot water from entering your pool.

Pros of a Solar Pool Heater

Pool solar panels
Photo Credit: Brandon Shaw / Flickr / CC BY-SA 2.0

Saves on Energy Bills

The most significant advantage of using solar pool heaters is that sunlight is free. Since there’s no energy cost, solar pool heaters cut down on the cost of your utilities. Replacing your current traditional electric or gas pool heater with solar will quickly pay back the initial investment by what you save on energy bills.

Renewable energy from the sun heats your pool, so your energy bill is reduced by 50% to 80% compared to gas or electric heating methods. Also, you won’t be faced with consistent increases in gas and electricity costs.

To heat an outdoor swimming pool during the swimming season with a gas pump costs roughly $1,700. To heat that same pool with a solar pool heating system can be as little as $30 to $74 per swimming season.

Reliable

You can rely on solar-powered pool heaters to provide consistent heating year-round. Even if it’s cold outside, you will be able to enjoy your swimming pool. Depending on the weather, solar pool heaters increase an unheated pool by 8 to 12 degrees, reaching between 78 and 85 degrees. Most people don’t use their heaters during the summer months since the water can reach over 80 degrees on its own.

Solar pool heaters automatically operate whenever the sun is out so that your pool is ready when you are. Although gas heaters might seem better for faster heating at a higher temperature, they provide that comfort at a much higher cost than a solar pool heater.

Long Lifespan

Solar pool heaters are low maintenance compared to other types of pool heaters. When you properly maintain your solar panels, they last 25 to 30 years and typically come with a 12-year warranty. Gas and electric heaters generally only last five to 10 years.

Compatible with Any Home and Pool

Just like gas and electric pool heaters, solar pool heaters are compatible with any size or shape pool. Solar pool heaters are typically mounted on the roof since there is plenty of space and sunlight. They can be mounted on flat, tile, and metal roofs and can also be mounted a few inches to several feet above the ground on an adjustable rack.

Eco-friendly

All forms of electricity have an environmental impact on the air, water and land. Using electricity more efficiently reduces both the amount of fuel and the amount of greenhouse gasses and air pollution.

Using energy sources that rely on gas or electricity can add to the greenhouse effect. Installing a solar system to heat your pool is an easy way to make a genuine effort to protect the planet. Homeowners who are concerned about the impact they have on the environment often turn to solar heating to cut their carbon footprint.

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Cons of a Solar Pool Heater

Side Solar PV Pool Heater
Photo Credit: Noya Fields / Flickr / CC BY-SA 2.0

Pool Takes Longer to Heat Initially

In most cases, solar pool heaters need several days to warm the pool to your preferred temperature after the initial installation before they maintain the optimal temperature. However, they usually maintain your preferred temperature for much longer than traditional gas or electric heaters after they reach the required temperature.

Expensive to Install

Although solar systems will save you money in the long run, they’re pricy upfront. A solar pool heater costs anywhere between $2,835 to $7,335.

The cost is why most people choose to forego solar-powered pool heating systems in favor of gas heaters or heat pumps which generally cost around $2,000-$4,500.

Weather Determines Effectiveness

Solar pool heaters are designed to operate from the sun’s heat, so they will not efficiently heat your pool during overcast days, during the night, or in regions of the country that are not as sunny. This means you’ll have to expect any night swims to be on the nippy side.

How to Select a Solar Pool Heater

You should do the following before you purchase and install your solar pool heating system:

  • Determine size: Your solar collector’s surface area should be 50% to 100% of the pool’s surface area. If you live in cooler or cloudy areas, you will want to be closer to 100%. You’ll also need a properly sized pool pump.
  • Determine sun exposure: A solar pool heater depends on the sun’s energy. But, even if you don’t live in a climate that’s sunny, the panels should still receive enough solar energy if they’re placed in an area that faces south and is not shady.
  • Determine placement and angle: The system’s performance is affected by both the placement and angle of the collector. Collectors should be mounted somewhere that provides enough sun exposure either on the roof or anywhere near the swimming pool.
  • Determine efficiency: Solar pool heating system efficiency is determined by its thermal performance rating. The higher the number, the greater the efficiency. This rating is measured by British thermal units per square foot per day: Btu/(ft2day) or by kilowatt hours per square meter per day: kWh/(m2day).
  • Compare prices: When choosing your solar pool heater, consider all of the factors involved. To estimate and compare costs, you need to know the collector’s thermal performance rating, the total number of collectors for the area, and the total cost of installation. 

How to Determine the Size of your Solar Pool Heater

There are a few things you need to know to determine what size solar pool heating system you need:

  • The Size of Your Pool: The surface area of your solar pool heater should equal half or all of your pool’s surface area.
  • Your Regional Temperature: If you live in a cold or cloudy climate, you will probably need to increase the ratio of solar collectors to pool surface area.
  • Length of the Swimming Season: Adding more square footage of collectors will increase your swimming season. Homeowners who live somewhere like California or Florida typically size their pool heaters at 60% to 70% of the pool’s surface area.  
  • Your Preferred Pool Temperature: If it boils down to your heating preference, you may decide you want less or more solar collectors than calculated. You can always consult your installer for help deciding the best course of action.

Cost of a Solar Pool Heater

The national average cost to install a solar pool heating system is roughly $5,085. You should expect to pay at least $2,000 and up to $7,500 for the unit itself, with another $500 to $2,000 added in labor costs for installation. It could take up to seven years for the system to pay for itself.

FAQ About Solar Pool Heaters

How warm does a solar-heated pool get?

Solar heating systems can maintain a comfortable swimming temperature by raising the pool temperature by at least 8 to 12 degrees Fahrenheit above the normal water temperature.

How many solar panels do I need for my pool?

The average pool has 600 square feet of surface area and will need a total of 300 square feet of solar panels to heat it properly. A single solar panel has a surface area of 50 square feet, so six solar panels will have a total surface area of 300 square feet.

Can you DIY install a solar pool heater?

No. Only someone who is an experienced professional with plumbing and electrical wiring should install a solar pool heating system.

When to Hire a Pro

Clean energy is the way of the future, so don’t get stuck in the past heating water with your old pool heater. Enjoy your pool all year without concern about emissions.

If you are in the market for a solar pool heating system and want to reduce your carbon footprint, contact a solar roofing professional in your area.

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Main Image Credit: Brandon Shaw / Flickr / CC BY-SA 2.0

Lydian Pine

Lydian Pine is a creative writer and studio artist whose work first debuted in a short story anthology. She graduated from the University of North Texas in 2020 and enjoys video games, theatre, and swimming. Lately, she has started to study entomology as a hobby.