Are Pool Heaters Expensive To Run?

Pool heaters and the cost to heat a swimming pool are a hot topic (pun intended!) Is gas pool heating better than a pool heat pump? What costs more to run? More importantly, how do you decide? Answer the following questions about heating your pool and read on to find the best fit for you.

  1. Do you want to swim right through winter (less affordable) or extend the swimming season by a couple of months (more affordable)?
  2. Do you want to take the chill off with 26 degree water temperature (more affordable) or want warm 28+ degree water (less affordable)?
  3. Is your pool concrete (less affordable) or fibreglass (more affordable)? Fibreglass pools are typically warmer than concrete. Read more here.
  4. Is your deep end over 2m deep (less affordable) or a standard depth of around 1.7m (more affordable)?
  5. Do you have a quality pool blanket in conjunction with your heater (more affordable) or no pool blanket (less affordable)?
  6. Are you on mains gas (more affordable) or bottled gas (less affordable)?
  7. Do you live in a warmer climate like Brisbane (more affordable) or cooler climates like Melbourne (less affordable).

There are a lot of variables that make a significant impact on the operating cost of your pool heater. If you heat your pool, you will notice a difference in your gas or power bill. Most pool owners use heaters at the beginning and end of a season and heat to a more efficient 26 degrees. Adding 2 degrees, up to 28 degrees, can double the operating cost. A pool blanket is essential. At around $500 for a 400 Micron thick pool blanket, you will save at least 50% in your heating bill which will offset the blanket cost quickly.

Extending the season also means your pump, filter and chlorinator will be running at a higher output for more months a year and you’ll spend more on chemicals and maintenance. The alternative is to set up a separate .5 horsepower pump to pump the heated water into your pool independently of the main pump, filter and chlorinator.  We’ve yet to find a pool owner with heating that regrets the decision however you need to make sure it is right for you. Learn more about pool pumps here.

What are the options? 

Gas Pool Heater

A gas heater is just like your instant gas hot water heater at home. Water passes through the internal piping exposed to gas flames which rapidly heats the water. Your pool pump then pumps the warm water into your pool. As a general rule, allow around 24 hours to achieve a 12 degree temperature increase. Gas heaters run on Natural or Liquid Petroleum Gas (LPG) which is the same as the gas to your house. If you are on gas bottles rather than mains gas, consider a heat pump as gas heaters use a lot of gas.

Like any heater (inside or out), energy efficiency is paramount. Gas heaters have a much higher LPM output rate than heat pumps which makes them gas hungry. A cheap heater won’t be efficient and will cost you more with higher gas bills. A quality gas heater with a five year warranty will relieve your bank account of between $4,800 and $9,700 depending on pool size.

Let's assume you are heating a 7x4m (42,000 litres) fibreglass swimming pool to 26 degrees in Sydney to add two months to your swimming season. Once your pool is up to temperature, it will cost around $150 per month in gas in October and April to heat your pool with a pool cover. Without a pool cover, the cost jumps to $300 per month. Bump up the temperature by 2 degrees to 28 degrees and the cost is $210 per month with a cover and $400 without a cover.

Pool Heat Pumps

Heat pumps are very similar to your reverse cycle air-conditioning at home. A condenser uses heat from the outside air to warm up your water. They are awesomely efficient in warm climates where the ambient air temperature is already warm. If the outside air temperature is cool, heat pumps tend to struggle to heat efficiently. Gas heaters generally trump heat pumps if you are in southern NSW or Victoria. The LPM output rate is much lower than gas so heating up times are also longer. Allow 48+ hours for a 12 degree increase.

With the invention of heat pump inverters (the pump speed cycles down as the set temperature is achieved), they are now energy efficient. How efficient? Up to 70% cheaper to operate than gas. Heat pumps can also be remotely controlled through your smartphone depending on the brand you choose. Quality brands will offer warranties up to 10 years. Entry level inverter heat pumps start around $4,000 and can go as high as $15,000 for a monster-sized unit that could heat the whole neighbourhood (ok, that’s an exaggeration).

Let's again assume you are heating a 7x4m (42,000 litres) fibreglass swimming pool to 26 degrees in Sydney to add two months to your swimming season. Once your pool is up to temperature, it will cost around $105 per month in power use in October and April to heat your pool with a pool cover. Without a pool cover, the cost jumps to $180 per month.  Bump up the temperature by 2 degrees to 28 degrees and the cost is $143 per month with a cover and $230 without a cover.  In a warmer climate like Queensland, the operational cost of a heat pump is around 40% cheaper.

There are so many variables with the operational costs of pool heating that we recommend you head to www.astral.com.au/tools-calculators and use their heating calculators. Even if you buy a different brand, the information is still really helpful.

Key Takeaway – If you are looking to extend your swimming season by a couple of months when the outside temperature is still relatively warm, a heat pump will work nicely and save money on operating costs. If you want to be swimming in the middle of winter in Melbourne at a nice 28 degrees, go with gas.

If you would like to learn more about the differences between concrete, vinyl liner and fibreglass pools, you can download our very popular and free The Essentials You Need To Know Before Buying A Pool e-Guide here. 

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Rohan Taylor
About The Author

Rohan Taylor

My wife and I grew up playing in swimming pools. Our daughters learnt to swim in our backyard fibreglass swimming pool. There is nothing quite like hearing kids splashing about and giggling. As pools do, our pool became a social magnet for friends, family and neighbours which we loved. Helping customers to have their own pool and saving customers thousands on their pool and equipment is the best job in the world.

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