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. With an energy-efficient heat pump, you can extend your swimming season well beyond summer – without breaking the bank.
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.
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.
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:
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.
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.
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.
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.
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!
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:
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.
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:
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 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.
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.
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 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.
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.
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.
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.
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.
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.
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.