Pool Spa Life
Pool Spa Life

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What does it really cost to run your pool?

In the dark when it comes to how much your pool costs to run each year? You may have a vague idea, but seasonality impacts on pool usage, chemical requirements, evaporation and energy use, making it hard to determine an annual figure.

If you don’t have a handle on your current outlay, you can’t know if there’s potential to save money – something that plenty of homeowners are keen to do in times of rising interest rates.

There are three basic areas of expenditure; energy consumption, water usage and chemical costs, all of which are subject to fluctuation throughout the year.

When it comes to energy use, there are plenty of variables in the equation including the type of equipment and how long you run it each day. Your geographic location has a massive influence on the retail kilowatt hour (kWh) price, which varies wildly from state to state across Australia and regionally throughout NZ.  

Water consumption is based on evaporative loss, which obviously increases over hot summer months. Evaporation is generally offset to some degree by rain, but changing weather patterns can throw the numbers out from one quarter to the next.

Finally, there are chemical costs – something that varies from household to household but can be reasonably approximated for the year if you know which chemicals you use, the water volume your pool holds and the average per kilo price of each specific product.

Energy costs

It’s no surprise that energy costs are spiralling. We’ve been told to expect continued increases for at least the next couple of years due to a range of external forces including a reliance on fossil fuels, profiteering by gas corporations off the back of the Russia Ukraine conflict and an aging local energy infrastructure.  

While renewables like solar and wind are on the rise, our national energy system still relies heavily on coal and gas. According to the Climate Council, the wholesale prices for both have roughly quadrupled since the 2020-21 financial year and those increases have naturally been passed on to the consumer.

Depending on the individual setup, the average pool uses power for a range of functions including filtration, cleaning and heating. Swimming pool heating is an comprehensive energy-related subject in its own right and we’ve written about it extensively in past issues of the magazine and on our website blogs. You can find plenty of information on the available types of pool heating on the Pool&Spa website. Just visit www.poolspalife.com.au and search ‘heating’.

Under the pump

For now, we’ll concentrate on the filter pump – one of the more energy intensive pieces of pool equipment. The pump works hard to maintain a clean and algae free pool, running probably six to eight hours a day in summer and four or so in winter. The trick here is to aim for one of the more energy efficient models – as a rule, a variable speed pump offers benefit over a single speed variety, as lowering the speed means the pump is not working as hard at specific times throughout the day and therefore drawing less power.

Ratings and rewards

Australia’s E3 Program requires swimming pool pumps to feature an energy rating label, which includes the pump’s energy consumption figure in kilowatt hours based on standardised testing (using a 50,000 litre pool as a benchmark) and assigns a star rating from one to 10 stars, with 10 being the most efficient.

Armed with this info and the kWh price your energy retailer charges – which is listed on your bill – you can easily work out the yearly running costs of a specific pump model. Current energy prices are a bit of moving feast and subject to huge variances from state to state. For example, in January this year the average kWh price in Victoria was 20.95c/kWh, while it was almost double that in South Australia at 36.11c/kWh, according to consumer comparison site, Canstar Blue.

For additional assurance, the Climate Care Certified (CCC) program provides independent third-party verification that swimming pool products, systems and installations are designed, manufactured and built to meet market and consumer needs in compliance with all required regulations, standards, licenses and codes.

CCC is an initiative of the Swimming Pool & Spa Association of Australia and New Zealand (SPASA) and is recognised as the industry’s efficiency and sustainability certification program. Because participation is voluntary, you know that certified vendors are serious about the industry and the environment. They’re also committed to delivering sustainable choices and innovations that help you make informed purchasing decisions — decisions that reduce water and energy consumption and save you money. You can find further information on the CCC website (www.climatecarecertified.com), including a list of certified swimming pool pumps.

Water costs

Beyond the initial fill, the bulk of water use in residential pools is compensation for evaporative loss, which varies seasonally and geographically. The evaporation rate is influenced by your pool’s surface area (the width x the length), the temperature of both the air and the water, humidity levels and other ambient conditions including wind.

To give you a general idea, Australia’s Bureau of Meteorology (BOM) publishes averaged annual, seasonal and monthly evaporation information from across the country based on historical data. It doesn’t allow for rainfall offsets but clearly illustrates the huge water loss variations by season for each region in the country. Not surprisingly, summer is where the action is, and dry heat contributes more to evaporation than high humidity. Based on the BOM’s summer data, the daily evaporation rate for pool in Sydney is just over 6mm, while for Perth, it’s somewhere between 8-9mm.

Calculating losses

So, what does that number mean, relative to your pool? Using those locations as examples: a 6mm evaporation rate in Sydney equates to six litres of water per square metre every day and a 9mm evaporation rate in Perth indicates losses of 9 litres per square metre every day.

In Sydney, 9m x 4m (36m2) pool will lose 216 litres every day and the same sized pool in Perth will lose 324 litres. Looking at a six-month swimming season and averaging out the numbers, it’s conceivable your pool will lose somewhere between 40,000 and 60,000 litres in that time period.

Of course, these figures are only based on averaged BOM data, not on the actual conditions at your place. Evaporation rates are also influenced by things like wind and direct sun exposure and if you are using pool heating. Evaporative losses are higher when the difference between the water and air temperature is greater, which means the real damage might be happening while you’re asleep.

Go undercover

The single biggest thing you can do to minimise evaporation is to utilise a pool cover, which can limit losses by more than 95% when correctly fitted. Covers and blankets also keep leaf litter out of the pool – which has a flow on effect for cleaning and chemical use – and can trap heat, keeping the water toasty and extending the swimming season even longer. For more information, check out the certified covers and blankets listed on the CCC website.

To get a general number, take a look at your last water bill and find the kilolitre (kL) unit price. At first glance, the final yearly dollar value required to compensate for estimated evaporation may not seem that large, but it’s worth remembering that water is an unpredictable commodity and that retail kL pricing can – and does – change quickly. For example, Sydney Water’s current household water usage charge is $2.50/kL, with a disclaimer that it will increase more than 50% (to $3.38/kL) if dam levels drop below 60%, a metric that’s out of everyone’s control.

Chemical costs

Depending on the type of pool (saltwater, mineral or freshwater) system you have and the sanitisation method you are using, there will be some cost associated with the use of chemicals – whether for sanitisation, water balance or other specialist treatments.

Of course, pool water has to be adequately sanitised, which in many cases means using products like sodium hypochlorite, calcium hypochlorite or salt (when combined with a saltwater cell) to kill bacteria, algae and other contaminants.

Then there are additives to balance the water – to ensure total alkalinity is stable, to raise or decrease pH levels, to ensure that calcium levels are maintained and ensure the sanitiser in your pool is protected from UV rays, which can degrade or burn off the effectiveness. In addition to these basics, there are other specialist products like algaecides, phosphate remover (algae feeds on phosphate), clarifiers, stain and scale prevention products and shock treatments.

Every pool is essentially a unique chemical equation, no matter what type. The inclusion of one chemical or additive can create a need for another to ensure the perfect water conditions. For example, mineral swimming pools use less chlorine than a saltwater chlorinated pool, but the addition of potassium and magnesium can often increase water hardness. Depending on the mineral mix you use, this may then require a chemical softener to compensate.

While this can seem a bit overwhelming and reads like a laundry list of confusing products, your specific pool is its own environment. It will require some or all of these additives in varying amounts, depending on your chosen sanitisation method, the other systems employed and the unique conditions of your pool environment. This makes chemical costs a bit of a ‘how long’s a piece of string?’ calculation, but you can safely expect to spend at least a few hundred dollars a year keeping the water in check.

As always, consult your pool shop professional or certified pool technician for accurate advice. Automatic dosing systems can also take the guesswork out of maintenance and have the twofold benefit of making it easier to work out annual chemical budgets. Technology advances are changing the landscape every day, with a focus on saving and sustainability increasingly driving product design. There’s a wealth of information available on the www.poolspalifecom.au website, with links to products and other technical articles that can help point you make better decisions when it comes to your pool.  

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