The Ultimate Guide to Choosing Mini Pool Heat Pump

Swimming pool heat pumps offer warm pool water at a fraction of the cost of gas pool heaters, and unlike solar heaters, continue to heat the pool during cloudy, rainy periods.

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Advantages of using a heat pump

Pool heat pumps work similar to a home heat pump. It acts like a reverse air conditioner, removing the ambient temperature in the air, with the use of an evaporator coil, liquid refrigerant and a compressor. The heat from the outside air is transferred to the pool water moving through the heat pump.

• No emissions and very low energy use
• Reliable heater, requires no maintenance
• No dangerous gas or flames used
• Easy to install, operate and troubleshoot
• Highly efficient, cheap to operate.

This blog will help you select the best pool heat pump for your pool size and usage patterns, and answer some questions about heat pumps along the way:

Sizing a heat pump

Pool heat pumps are typically matched to the number of gallons in your pool. If you don't know or aren't sure how many gallons you have, measure your pool, and use this pool volume calculator tool.

Some heat pump manufacturers don't list the gallons, but list their heaters in terms of the BTU output. Most models are in the range of 50K (50,000) BTU's - to 125K BTU's.

50K BTU heat pumps are meant for small pools, or aboveground pools, under 12,000 gallons. It will work on larger pools, but heating will be slow and total temperature rise may not be what you desire.

You'll need to consider pool size and the desired temperature change when selecting a heat pump for your swimming pool. Other factors, such as the average air temperature, humidity and wind speeds, will also influence a heat pump's ability to warm the pool water. Figuring on a temperature increase of 1-1.25 degrees per hour, you can use the following equation to get an approximate heat pump BTU requirement:

(Surface Area) x (Temperature Increase) x 12 = (Minimum BTU Needed)

For example, we'll use a rectangular pool 14 ft. wide by 28 ft. long. During the coldest month of use, the pool owner wants to increase the water temperature by around 20 degrees Fahrenheit.

(14 x 28) x 20 x 12 = 94,000+ BTU

BTU Guidelines

If you happen to know the volume of your pool in gallons, you can also follow this general guideline for heat pump BTUs:

Heat pumps max out around 135,000 to 150,000 BTU, so larger pools will take longer to heat. It's important to purchase a properly sized unit in order to maximize energy savings. Using a solar pool cover can also help reduce heat loss and boost efficiency.

The larger the BTU output, the faster the heating (still slow by gas pool heater standards) - and the greater temperature rise the pool heat pump can achieve. A nice sized heat pump can bring the pool up 30 degrees (or from 50 to 80 degrees).

Another factor that could affect the size of heat pump that you buy; if you have high winds and no pool cover, you will suffer from a great deal of heat loss off the top of the pool. If you do have wind blocks and/or an automatic pool cover, you could potentially buy a smaller heat pump.

Selecting a heat pump brand

With so many on the heat pump bandwagon, there are a lot of brands to choose from. Many of the names you may not recognize, like TropiCal and AquaCal. These companies are the originators of pool heat pumps, selling thousands throughout the  80's and 90's. As sales increased, big brands like Hayward and Pentair took notice, who are now making pool heat pumps as well.

To make it easier to choose from, we list 6 different pool heat pump models, from 4 manufacturers. Prices vary according to the features installed on these different models. Some of the most popular options out there that all models have is:

• Titanium Heat Exchanger
• Thermoplastic jacket or exterior
• Digital display, electronic controls
• Environmentally friendly R410A refrigerant

Some models will have more advanced diagnostic indicators (idiot lights), a super-quiet Scroll compressor, or a more compact design. Warranty is another point of differentiation between our 6 models of heat pumps. Finally, the high end pool heat pumps have the ability to also cool the pool, in the event that summer heat brings the pool water to unbearable temperatures!

Installing a heat pump

There's not much difference in installation methods among our pool heat pumps. There are some size considerations, so if you have a smaller space, look to the product dimensions in the brochure or the owner's manual (linked from our heat pump pages).

All heat pumps will need to be installed on a level platform or slab. You cut the pipe after the filter and any chlorinator, then connect the pool plumbing in and out of the heat pump. Heat pumps require a 30-60 amp breaker, depending on their BTU output size.

Your heat pump installation may require bringing more power to the equipment pad, or if you're lucky, you have enough room left to add the required breaker size to the panel. To be safe, use a qualified electrician to perform the electrical hook-up on your new heat pump.

Pool Heat Pump Buyer's Guide

Aqua Cal

One of the oldest and largest manufacturers of heat pumps. Aqua Cal does not make any other products besides heat pumps for pools in both residential and commercial applications. Their heat exchanger is titanium. Aqua Cal has an easy to read digital display, dual thermostat and whisper quiet fan motor. The thermostat has a lockout option, which prevents anyone from adjusting the pool temperature.

Aqua Pro

The AquaPro heat pump has a titanium heat exchanger with a 5 yr. warranty on the heat exchanger. Most of the units have a digital display with a dual thermostat. The housing on the heat pump is very durable and is weather resistant. Aqua Pro is one of the leaders in pool heat pumps, and one of the first manufacturers in Florida.

Pentair UltraTemp

The UltraTemp is Pentair's original heat pump with a titanium heat exchanger to help prevent and protect against chemical corrosion. The cabinet on the UltraTemp is weather resistant and will help ensure optimal performance during any climate. Available in three sizes, and comes in a heat/cool model to both heat and cool the pool, and comes with many advanced features and benefits.

Hayward HeatPro

Hayward purchased EUS in , and added the Heat Pro, which has a titanium heat exchanger to help prevent from chemical damage and also Hayward Quiet technology built into their heat pump. The compressor and fan blade helps reduce noise. Hayward Heat Pro has an Ultra Gold corrosion resistant evaporator coil which helps provide excellent durability even in coastal environments.

Raypak Classic Series

These heat pumps feature robust construction, and full featured design elements. Easy-to-use digital controller and simple water line hook ups make operation and installation a snap! ETL Listed and AHRI Certified. We also carry the Raypak Heat Cool Heat Pumps, to allow you to heat or cool the pool water, as needed.

TropiCal

An economical and environmentally-friendly way to heat your pool. Using titanium heat exchangers and TropiCal’s patented counter-flow water management system, this pump harnesses the power of its sealed ventilator motor. Microprocessor controlled auto defrost keeps the TropiCal running even when temps dip into the 40s.

Let’s face it, most backyard pools are only used for three or four months a year. The rest of the time, they’re either closed, ignored or become a habitat for aquatic birds! But just because the temperature drops, doesn’t mean you need to put your pool toys away. A swimming pool heat pump is the most energy-efficient way to extend your swimming season without skyrocketing energy bills.

If you’ve been thinking about getting a heat pump but don’t know where to start, you’ve come to the right place. In this article, we cover everything you need to know about heat pumps, like how they work, why they’re so popular and how to choose the right one for your pool. Then we finish with energy-saving tips and a handy troubleshooting guide. 

What is a Swimming Pool Heat Pump and How Does It Work?

A pool heat pump is a simple and energy-efficient way to keep your pool or spa water warm all year round. But unlike a gas or electric pool heater, it doesn’t actually generate heat. Instead, it pulls warmth from the air outside and uses it to heat your pool water.

 Here’s how it works. When your heat pump is on, a fan draws warm air into the heat pump’s evaporator coil. The air heats up the liquid refrigerant inside, turning it into a gas. The gas then passes through a compressor that heats it further. Once it reaches a certain temperature, it moves into the heat exchanger (a tube within a tube) and heats up your pool water. When this is done, the water returns to your pool and the gas goes back to liquid form and starts the process all over again. 

In general, heat pumps rely on warm ambient temperatures, which means they work more effectively in temperate or humid climates. For best results, the air temperature should be 10 degrees Celsius or higher. (Having said that, some units, like the Eco Inverter Heat Pump and Viron Heat Pump range, can perform in temperatures as low as 7 degrees Celsius.)

Unfortunately, if you live in a cold climate or experience cold winters, pool heat pumps may not be a suitable option (this also applies to solar pool heating). Instead, you’re better off with a gas pool heater. While it’s less energy efficient to run, you get the water temperature you desire – and a lot faster too. For a detailed comparison of pool heating systems, see this article.

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Advantages of a pool heat pump

While we’ve already touched on some of these, here are four reasons why many pool owners choose heat pumps over other pool heating systems:

1. Energy-efficient

One of the best things about pool heat pumps is their energy efficiency. While they still require electricity to run, they don’t need it to generate heat, which means they use far less power to heat your pool than gas heaters. A heat pump’s efficiency is usually measured by a Coefficient of Performance (COP) rating. As a rule, the higher the rating, the better the efficiency. 

So if you’ve got a heat pump with a COP of 8, you get 800 units of energy transferred to the pool, which is pretty good. If you get an inverter heat pump, you get even more efficiency. For example, the Eco Inverter Heat Pump has a COP of 10, making it 10–35 per cent more energy-efficient than non-inverter heat pumps. Additionally, if you want something even more efficient, the Viron Heat Pump range is a another great choice for your pool heating system, with a COP of up to 13. 

2. Durable

Heat pumps usually have a longer lifespan than other heating systems. The average lifespan of a gas heater is 5–10 years and a solar pool heater is 15 years. A pool heat pump, on the other hand, can last 10–20 years. This is because it doesn’t actively produce heat; it transfers it, which means it doesn’t have to work as hard. 

Gas heaters, however, actively produce heat and wear out faster. As for solar panels, exposure to the elements can cause denting, rust or cockatoo damage (they love chewing on solar strips and manifolds!), so they may need regular servicing or replacement. 

3. Economical

While pool heat pumps can cost anywhere between $3,600 and $6,900, they tend to be more affordable than other options. Solar heating can cost about $2,750–$6,350, but installation can push these costs higher, depending on the size of your pool and the complexity of the set-up (some installations can be as much as $8,500!). Gas heating can be anywhere between $3,000 and $10,000, and installation can cost $1,500–$6,000.

Running costs for pool heat pumps are also lower than they would be for electric or gas heaters. For example, an electric heat pump can cost $250–$750 per year, while gas heating can cost $500–$1,500 per year. Solar heating, on the other hand, is economical and can run for as little as $1 a day. But as mentioned earlier, installation and maintenance costs can be high, and not all homes or climates are suited to this heating system. 

4. Easy maintenance

Compared to other heating systems, heat pumps are relatively easy to maintain. When something goes wrong, you turn them off, remove any clogging, check for leaks and adjust the thermostat. Solar panels, on the other hand, are less accessible, and due to the technology, can be harder to troubleshoot yourself. Similarly, a gas pool heater may require a plumber to check for damage, low/high pressure or gas leaks. 

How to Choose the Best Pool Heat Pump – Cost & Features

There are a few factors to consider when you’re buying a pool heat pump. These include the size of your pool, where it’s located, your local climate, frequency of use and your preferred water temperature. Once you know these things, you can use our online heat pump calculator to find the right-sized heat pump for your pool. Alternatively, you can contact your pool shop for advice. For more information on sizing a pool pump, see this article.

Once you’ve got a shortlist, it’s time to look at the COP rating. A higher rating means faster heating times, less energy consumption and lower running costs. Typically, COPs for standard heat pumps range from 3 to 7, while inverter heat pumps can be 10 or more. 

Other heat pump features to consider are noise levels (inverter models tend to be quieter), heating times (some can take as little as 12 hours, while others can be as long as 72 hours), frost protection, warranty and price. 

Top tip: It’s more energy-efficient to run a large heat pump at half capacity than a small one at full capacity!

Installing a pool heat pump

The best time to install a heat pump is when you first get a pool. However, it can still be retrofitted by an electrician or pool technician, even if you’ve got a different heating system. Here are some points to keep in mind:

• Ensure there’s enough power to run the heat pump. 
• Position the heat pump in a well-ventilated area (see your manual for clearance requirements). 
• Keep the heat pump close to the pool (long pipes can slow down circulation).
• To avoid water damage, keep the unit away from leaky gutters or sprinklers.
• Use a level concrete base to minimise vibration.
• Ensure the heat pump is placed last in your flow system (except when you’ve got a chlorinator; this can corrode the heat exchanger).
• Insulate the pipes to reduce heat loss.

How to maintain a pool heat pump

Once it’s up and running, a pool heat pump is easy to maintain. Just check it regularly for blockages, leaks and loose connections, and remove any debris clogging the air inlet. To avoid circulation issues that could stop your heater from working, run your pump for at least 8–10 hours a day and keep your filter, skimmers and pool pump basket free of debris. 

An important thing to remember is that heat pumps can corrode if your pool water isn’t balanced. To prevent this, check your water chemistry weekly and adjust accordingly. Last, get an annual service to check electrical components and switches, test water flow, test the compressor, measure voltage, identify leaks and clean the inside of the unit. 

Energy-saving tips for pool heat pumps

There’s no doubt that pool heating – even when it’s energy-efficient – can hike up your energy bills. Here are some ways you can lower the costs:

• Use a pool cover. Not only do pool covers help retain heat and avoid overworking your heater, but they also keep out environmental debris, minimise evaporation and reduce running costs. What’s more, if you use a solar pool cover, it can harness heat from the sun to minimise the use of your heating system. 
• Turn your heater off during the off-season. If you’re going on holiday or closing your pool for winter, turn the heater off and keep the valves open. However, if there’s a risk of overnight freezing, drain the water from the heat pump and shut off the valves. 
• Keep the water temperature below 28 degrees Celsius. It’s best to keep your water temperature below 28 degrees Celsius. If it’s higher, not only will it increase your energy consumption, but it’ll also cause algae and bacteria to multiply (they thrive in warm water!). The last thing you want to do is keep shocking your pool or running the automatic cleaner!  
• Use an automatic timer. If your model can be programmed, allow the pool heat pump to run for a set number of hours, ideally during the warmest part of the day. This prevents your unit from running unnecessarily and wasting more energy. 

Troubleshooting your pool heat pump

Every pool heater has its problems – and pool heat pumps are no exception. If your heat pump isn’t heating, heats too slowly or leaves cold spots, below are some common causes and how to fix them:

Low water flow

Low water flow is a common cause of heat pump issues – and it’s usually because of a clogged pool filter. Heat pumps need good water circulation to work properly, so if you don’t have enough flow, your pool may take ages to heat up or not heat up at all. If this happens, check your filter pressure gauge to see if it’s time for a clean or backwash. If this doesn’t solve the problem, check your skimmer and pool pump baskets for debris. Once your filter and baskets are clear, it should improve circulation and get your heat pump working again.

Clogged evaporator coil

When your evaporator coil draws heat from the air, it can also pull in dust, dirt, leaves or grass clippings. This can clog the coil and make it difficult for your heat pump to work properly. To check for debris, turn off the unit and inspect the coils. If they look dirty, remove any surface dirt with gloves and hose the coils with water. Make sure the jet isn’t too strong or it could damage the unit. Avoid detergents or cleaners. 

Note: Don’t clean the interior of the unit yourself. This should be done by a trained technician, usually during your annual service.  

Low ambient temperature 

If you live in a cool or cold climate, it can be difficult for your unit to extract enough warm air to heat your pool. One way to counteract this is to place your heat pump in a sunny spot so it can heat water more quickly. However, if this doesn’t work or temperatures dip below zero at night (hello, Tasmanians!), consider an instant heating system, like a gas pool heater. 

Top tip: If you’ve got a gas heater but want to save money, consider adding a heat pump. This allows you to use the heat pump when the temperature is above 10 degrees (to save energy) and the gas heater on brisk winter days (for reliable heat). 

Water leaks

Water leaks in your pool heat pump are a common cause of heating problems. These can be caused by corrosion, broken gaskets or cracked fittings. Before you call a pool technician, though, check to see if it’s condensation or a genuine leak. Place a test strip in the puddle and see if it contains any chlorine. If it does, then it’s a bona fide leak. If it doesn’t, it’s just condensation and nothing to worry about.  

Note: Leaking refrigerant may also affect how your heat pump works. Check to see if you’ve got an error code on your digital display. If it matches up with a refrigerant leak, contact a heating, ventilation and air conditioning (HVAC) professional for service and advice.  

Wrong setting on the thermostat

Make sure the setting on the thermostat is higher than the desired temperature of the water. In general, if the pool’s temperature is higher than the thermostat, the unit won’t operate. If you adjust the thermostat to the right temperature and it still doesn’t heat the water, you may have a faulty thermostat. In that case, contact a pool heat pump technician.

Your heat pump is too small for the pool

When your pool takes longer than 48 hours to heat up, your pool heat pump may be too small for your pool. To find the right size, see our guide on sizing and choosing a pool heat pump. Getting a heat pump that’s correctly sized can help your pool heat up faster and more effectively – and save on running costs too.

Low speed on your variable speed pump

Variable speed pumps are a great way to lower energy bills and make pool circulation more efficient. However, when you use the lowest setting, there isn’t always enough water flow to trigger the heater. Try raising the speed and see if the heater kicks in. 

Connection issues

Check to see if the heat pump has been disconnected or if the circuit breaker was activated. It’s not unusual for pets, children or bad weather to loosen these connections. If your heat pump still won’t start, call a pool technician.

Your heat pump is too old

When pool heat pumps are at the end of their life, they don’t work as effectively anymore. If your unit is more than 15 years old, it could be time for an upgrade. Before you do this, though, arrange for an inspection. Who knows? A minor repair could give it a few more years of life. But even if you upgrade, newer models are faster and more energy-efficient, which could save time and money in the long run. 

Summing up

Compared to gas and solar pool heating, pool heat pumps are a reliable, easy and energy-efficient option for your backyard pool. As long as you position them close to the pool, provide good ventilation and keep the vents clean, you’ll have toasty pool water all year round.

If you live in a cold climate, pool heat pumps (or solar heaters, for that matter) might not work as effectively. If that’s the case, consider using a gas heater. While it’s more expensive to run, it provides instant and reliable heat for your pool.

But whatever heating system you use, here are these four energy-saving tips you should remember: cover your pool at night (or when it’s not being used), turn off the heater during non-swimming periods, keep the temperature below 28 degrees Celsius and use an automatic timer. 

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