Factors to Consider When Calculating Pool Pump Size

Factors to Consider When Calculating Pool Pump Size

Many Perth, WA, residents enjoy the freedom and luxury of taking a dip in their swimming pools on a hot day. Proper maintenance is a must to enjoy a pool for years to come, and that includes replacing a damaged or broken pool pump. However, not every pool pump size will work for your pool’s specific needs.

Determining the right pump size for a pool is one of the most common frustrations swimming pool owners have. Thankfully, the experts at 1 Pool Care is here to provide you with all the details you need to know to make the most informed decisions about your pool’s pump needs. Our team can install your new pump quickly and efficiently so that you can enjoy your backyard water feature in no time.

Consult our guide below to learn how to calculate pool pump sizes and view some tips on selecting a suitable device for your needs.

Factors to Keep in Mind When Choosing the Best Pool Pump Size

Factors to Keep in Mind When Choosing the Best Pool Pump Size

Your pool pump is essential for its circulation system. It draws water into the skimmer and through the main drain. Then, it pushes pool water through a filter before returning the filtered water to the pool through the main returns.

A common misconception about pool pump sizes is that one size will fit all. Installing an appropriately sized pump is necessary for the health of your swimming pool system.

If the pump is too small, it will not have enough power to circulate and filter the pool water, making the water more vulnerable to an algae growth. Parts of your pool can also become stagnant from a lack of circulation, making those areas an ideal place for algae, moss, and other water-based contaminants to thrive.

However, an oversized pump will consume excessive energy and overpower the filtration system. Picking the wrong size could cause your filter and media to wear out quicker than it should, leading to more frequent replacements.

Finding the most appropriately sized pool pump is the best solution for optimal water circulation and filtration system. To find your pool pump size, you will need to consider four factors about your pool: the pool volume, turnover rate, maximum flow rate, and total dynamic head.

How to Calculate Your Pool’s Ideal Pump Size

Measure Your Pool

The first step is to determine the number of gallons or litres of water in your pool, which is its volume. To do that, you will need to take measurements of your pool to determine its water depth. The mathematical formula for learning your pool volume is relatively simple: pool length x pool width x average pool depth x 28.31 = pool volume by litres.

Most residential pools in Perth have a rectangular or square shape. To measure the general depth of your pool, you will need to take the depth of the pool’s shallow end, if one is present, and add it to the deep end’s depth. Then, you divide the sum of the figures by two.

For example, let’s say your pool has a 4-foot-deep shallow end and an 8-foot-deep deep end. Adding the depths gives you a sum of 12. By dividing 12 by two, you will learn that the average depth of your swimming pool is 6.

Once you measure your pool’s width and length and discover its average depth, you can plug the figures into the pool volume formula. If your pool is 30 feet by 15 feet with an average depth of 6, the formula will look like this: 30 feet x 15 feet x 6 feet x 28.31. The pool’s volume would be about 76,437 litres.

Keep track of this number. You will need it to help you determine your ideal pool pump size.

Irregularly Shaped Pools

Finding the volume of circular or irregularly shaped pools is more complex. They require different mathematical formulas. For instance, the basic formula for a circular pool’s water volume is 3.14 x radius squared x average depth x 28.31 = volume in litres.

Finding the radius is reasonably straightforward. Simply measure the distance of the circular pool’s widest part and divide it by two. Squaring the radius means multiplying the radius by itself.

In other words, if the broadest part of a round pool is 10m, dividing the figure by two will be five. Five multiplied by five or five squared is 25.

Kidney shaped or geometrically shaped pools are more complex to measure. You could try to divide your pool into rugged rectangular or round sections to determine its volume. However, it may be best to get professional help from pool maintenance professionals.

Find the Turnover Rate

Turnover rate is the length of time a pool pump will work to clean pool water. The rate is in hours.

Ideally, the turnover rate should be around six to eight hours. A higher rate could be a problem because it will force the pool pump to use too much energy, resulting in increased power bills. A lower rate can also be an issue because it takes time for the pump to filter the water.

There are exceptions to this rule. It is acceptable for some indoor residential swimming pools to have a four-hour turnover rate.

You can find the pool’s turnover rate by dividing its volume by the number of hours you want the pump to run. If the pool volume is 76,437 litres and you prefer to run the pump for six hours, you would divide 76,437 by six to get 12,739.5 litres. Your pump should cycle 12,739.5 litres of water within six hours.

Determine Flow Rate

A pool’s flow rate refers to how many litres its pump circulates per minute. The information will help you select the best pool pump size because most Australian pumps have litres per minute ratings. You will need to know the pool’s volume and turnover time to calculate the flow rate.

Using the previous example, let’s say the turnover rate is 12,739.5. Since the ratings are in minutes, you would divide that number by 60 to get 212.35, which is how much water the pump should cycle per minute.

Calculate the Pool’s Total Dynamic Head

The flow rate will help you learn your pool’s total dynamic head. This figure is a measurement in metres that helps determine the required performance level the right pump size will have to cycle the water effectively.

The total dynamic head refers to the amount of resistance the pump works against to draw water into itself from the pool’s basin before pushing it back into the pool. The calculation measures the friction your pump will encounter, potentially reducing water flow and forcing the pump to work harder to circulate and filter the pool water.

Friction or opposing forces that work against the pump will include the lengths of the pipes water flows through, including their angles, twists, and turns. It also consists of the slope of the pool pump and its filter.

Typically, inground pools have a total dynamic head of about 15 metres. Above ground pools usually have a 9-metre total dynamic head.

However, if you need to calculate the total dynamic head, you will need to add all the pipe lengths together. You will also need the flow rate and details about the pipe, including its depth, diameter, and material. Determining the total dynamic head is tricky for most people.

selecting the correct pool pump

Selecting the Right Pool Pump

Once you complete all the calculations necessary, you can select an appropriate pool pump size. When you visit a local pool accessories shop, the salesperson helping you will likely inquire about your pool’s volume, turnover rate, flow rate, or total dynamic head to recommend the best options.

If you are shopping alone in stores or online, it would be best to look at the pumps’ horsepower or Kilowatt rating. Most brands have packaging or manuals that break down the type of kilowatt rating and customers will need based on their turnover rate, flow rate, or total dynamic head.

You could go for a pump size with higher horsepower than your calculations recommend. More horsepower would speed up the rate at which the pump filters your pool water. However, the higher the horsepower, the more power the equipment will consume, so you might want to stay within the recommended six- to eight-hour timeframe.

When shopping for a pump, ensure that you select a model that has a flow rate that will accommodate your pool’s needs. The ideal equipment should have the closest number of litres per minute to the pool’s flow rate. You may need to round up, but that is acceptable because the pump will have more than enough power to keep your pool clean without reducing its flow rate.

When you determine which horsepower or kilowatt rating and flow rate will work for your pool, consider the other features to help your pool’s circulation system work more efficiently. For instance, some models have speed control, different motor types, or energy-efficiency features.

Single-Speed Pumps

The most popular pool pump type is the single-speed pump. This equipment has a motor and impeller that spins at one speed according to the motor’s horsepower. These pumps can consume substantial power when they run for extended periods.

Dual Speed Pumps

Dual speed pool pumps have low and high settings. The high option allows the pool pump to operate precisely like a single-speed pump. However, the low setting slows down the motor, making the equipment ideal for minor energy efficiency.

Variable Speed Pump

These energy-efficient pool pumps include a permanent magnetic motor, which make them much more efficient to run. They can run at any speed without producing excessive friction. Variable speed pumps also have a quieter operation and a longer lifespan than other pool pumps.

Choosing a Pool Pump for Above Ground Pools

Pool pumps are as important for above ground pools as they are for inground pools. The good news is that above ground pool pump sizes are relatively standard, so the calculations are simple.

To find the right size for a pool above ground, you will need to know the pool’s length and how much water it holds. Generally, a single horsepower pump works on pools up to 7.3 metres long with 58,000 litres of water or less. A 1.5 horsepower pool pump is best for above ground pools over 7.3 metres long with 58,000 litres of water or more.

Learn More About Pool Pump Sizes With 1 Pool Care

Calculating your pool pump size requires knowledge about your pool, including how many litres of water it holds, its flow rate, turnover rate, and total dynamic head. Using that data and the appropriate mathematical formulas will help you determine which pool pump size will work the best for your water feature.

The professionals at 1 Pool Care understand that pool care can be challenging. That is why we are available to take care of all your swimming pool maintenance needs. As the go-to source for quality, reliable pool services in Perth, WA, our licensed technicians provide pool pump repair on all makes and models.

After three decades of assisting Perth residential and commercial clients, our team has the expertise to help you troubleshoot equipment issues or offer advice about replacement parts. If you need assistance finding your pool pump size or installing new equipment, reach out to 1 Pool Care at 0456 75 75 75 today.

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