While many pool owners assume that all pool pumps are more or less the same, in reality there are many small differences between different makes and models. These small differences can affect how well the pump does its job, or they can simply make one pump easier to install than another. Today, we will walk you through how to choose which replacement pool pump is right for your pool.

Inground Pool Pumps Vs Above Ground Pool Pumps

The first thing you need to consider when replacing your pool pump is whether you have an inground or above ground pool. While it might sound obvious, not every pool owner understands that these two pools require different pumps. There are three main ways that these pumps differ; their electrical requirements, flow rate and their priming method.

  • Electrical Requirements. Above ground pool pumps operate on a 120V service while inground pool pumps typically operate on a 240V service. This means that above ground pool pumps can be plugged into any standard electrical socket while inground pumps will usually need to be hard wired to your electrical panel.
  • Flow Rate. Since inground pools typically have a much higher water volume than above ground pools, inground pool pumps are designed to move more water than above ground pool pumps. An above ground pool pump added to an inground pool simply won’t be able to move enough water to keep the water clear and safe to use. An inground pool pump added to an above ground pool will move the water too quickly through the plumbing and the filter won’t be able to properly do its job.
  • Priming. “Priming” is the process of filling the pump with water so that it can run properly. If the pump isn’t primed, the impeller will simply spin through the air that fills the wet end of the pump while it isn’t running. While above ground pumps don’t need to be primed (the water naturally fills the pump due to gravity even when it isn’t running), since inground pool pumps are located above the waterline of the pool they need to be able to prime themselves.

Check The Plumbing

Once you know which type of pump you need, the next step is to check the size of plumbing that your pool has. While 1-1/2″ wide plumbing is the industry standard for most pools, some inground pools are plumbed using 2″ or even 2-1/2″ wide plumbing. Many inground pool pumps are available with different plumbing sizes to match the plumbing in your pool.

While you can buy adapters to bridge a gap in sizing between your new pump and your pool plumbing, it is better to avoid doing this as it will affect how efficiently your pump can move water. If you have a larger inground pool, this inefficiency can be the difference between your water staying clear or going cloudy.

Note: When measuring your pool plumbing, you want to measure the opening in the centre (its “inside diameter”) rather than the full width of the plumbing (its “outside diameter”). 1-1/2″ PVC plumbing is actually pretty close to 2″ when measuring outside diameter, which can cause confusion.

Make Sure That Your Pump Is Properly Sized

Once you’ve confirmed the size of your plumbing you then need to choose a pump that is properly sized to your pool. As we just mentioned, pumps that are too small aren’t able to move enough water to keep the water in the pool clear and safe to use. Pumps that are too large will move the water too quickly through the filtration system, causing it to filter less effectively and even damaging it over time.

How To Size Your Pool Pump

So how do you make sure that your pool pump is properly sized? You first need to know the volume of your pool.

If you don’t already know the volume of your pool you can figure it out by first measuring it, then plugging those measurements into a tool like Pentair’s pool volume calculator.

Once you have the volume of your pool you can then figure out the ideal flow rate of the pool.

Check Flow Rates

A pool’s flow rate is simply the amount of water that flows through its filtration system (measured in gallons per minute). The “ideal flow rate” of a pool is the range of flow rates that will effectively filter the water while also maintaining energy efficiency.

To figure out the ideal flow rate of your pool, you can use Pool Research’s pool volume calculator. This free tool allows you to see how many gallons per minute that your new pump will need to produce in order to filter all of the water in the pool the minimum recommended 2 times per day.

Once you’ve determined the flow rate that your pool requires, check flow rates of each pool pump that you’re considering to see if they’re capable of meeting those requirements. In general, we recommend going with the smallest pump that can produce your needed flow rate as they will run more energy efficiently than a larger pump will. Better yet, you can purchase a variable speed pool pump.

Consider A Variable-Speed Pool Pump

Variable speed pumps are pool pumps that are able to change their flow rate on command by changing the speed of their impeller. Variable speed pool pumps have several advantages over traditional single speed pumps, most notably:

  • Energy efficiency. The slower the impeller is spinning, the less power the pump will consume. In fact, variable speed pumps consume up to 90% less than single speed pool pumps; saving the average pool owner anywhere from $300-$500 per year!
  • Programmability. Variable speed pumps can be programmed to change their speed over the course of the day; allowing you to save more money by running the pump more during off-peak energy times and less during on-peak times.
  • Noise level. Variable speed pumps run much quieter than single speed pumps.
  • Lifespan. Variable speed pumps also typically last much longer than single speed pumps as they rarely run at full speed, which means less wear and tear on the components of the pump.

Read More: How To Save Money With Variable Speed Pool Pumps

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