What is a Variable Speed Pool Pump & How Does It Work?

By Blue Cube on Thursday, 18th May 2023 in Tips & Tricks.
What is a Variable Speed Pool Pump & How Does It Work | Blue Cube Pools

Variable speed pumps or variable speed pool pumps, also commonly cited as VSPs or VS pumps, have been booming in popularity over the previous years. We’ve seen a growing interest in them and the eco-efficiency they can bring to a pool build. 

But what is a variable-speed pool pump? How do they work? And how can you best use them to your advantage? Find out in the rest of our handy guide.

So – what is a variable speed pump?

Variable-speed pool pumps can be a great way to save energy and money while keeping your pool clean, healthy, and safe for swimming. With their adjustable speeds, variable speed pumps allow you to control the flow of water in order to reduce noise levels and minimize electricity and energy costs.

The basic understanding of a variable speed pump is that the pump can be programmed at different speeds, essentially giving you more control over the energy consumption of the pool pump.

Plus, they come with advanced features like built-in timers that help you automate cleaning cycles or set specific time periods for running the pump at its full capacity. All this makes them an ideal choice for anyone looking to make their pool more efficient!

How do variable-speed swimming pool pumps work?

Where single-speed pumps only have one speed, variable-speed pool pumps can be adjusted to different speeds. They come with a motor that is controlled by a controller or an easy-to-use interface that allows you to program the speed of the pump and the duration of its run time.

The settings can then be used to adjust the flow and velocity of water, unlike a single-speed pool pump that requires you to manually adjust the valves each time the pump needs to run at a different speed. A variable-speed pump offers stored settings for recurring tasks such as cleaning cycles and filter changes, making swimming pool maintenance and operation easier.

How to set up your VSP

You can set the VSP’s speed depending on the usage of the pool. For example, if you have a busy weekend in which the pool is being frequently used, you can set your VS pool pump to high. This means the water turnover in the pool is the highest possible, and the quicker the pump pulls the water through the system cleaning it.

This can also work the other way around. If you had a weekend the pool wasn’t going to be used much or you’re going away, you could set the VS pump to a low setting. This in turn means the water will not get filtered through the system and cleaning it as much. Given the low usage of the pool, this is all wasted energy and money. 

A VSP can also be changed throughout the day. Many users have their VS pump set to change to a low speed overnight whilst they sleep.

This means the pump would work the same as a standard single-speed pump during the day and would change to a lower running speed at night saving energy and running costs.

Setting eco-friendly times like this can similarly be seen in heating systems within many modern homes. Below are findings from a case study on the Speck Badu Gamma Pumps. We’ve used the Gamma pump for this breakdown because it represents a middle-of-the-range pump, where price meets quality. 

Variable speed pump running costs

What about the cost and energy savings aspect of using a VSP? Can they actually save me money in the long run? The short answer: absolutely.

The below cost comparisons of a Speck Badu Gamma Single Phase and a Speck Badu Gamma VSP are made using a running time of 24 hours, for 7 months of the year. 

The VS pump would be used at a medium speed for 10 hours a day, whilst the pool is in use. Powered down overnight, when not in use. Costs are based on 30p per kW/h.

Speck Badu Gamma 23 – Single Phase (1.0Kw)

  • £1,240.85 at retail
  • £2,359.69 running costs per year
  • 7020kW a year

Speck Badu Gamma VS Pump (1.1Kw)

  • £1,851.52 at retail
  • £2,007.58 running costs per year
  • 5974kW a year

In short: the Speck Badu Gamma VSP is £610.67 more expensive upfront, but saves £352.11 in running costs per year and uses 1,046kW less a year.

This means as a customer you could feel the money-saving benefits of dual-speed pumps in under 2 years, given the above details. Like anything, these factors can change based on energy rates and other factors leading to a shorter or longer payback period. 


What is a pool pump inverter?

A pool pump inverter is a device that changes the frequency of the power supplied to the pump. This will then control the speed of the motor and the flow rate of the water in the pool.

Making your energy consumption more economical and saving you on running costs. Variable speed technology has been growing in popularity. The last few years have seen big uptakes of dual-speed pump technology in domestic swimming pools. 

One of the biggest selling points of a pump inverter is the claim that it can save you up to 60% on the running costs of a single-speed pump. These savings are possible by linking your existing pool circulation pump to an inverter.

Single-speed pool pumps invariably run at a higher flow rate than necessary. Fitting an inverter enables you to not only control the flow rate but the pump run times. This means that the flow rate can be reduced overnight or while away and the pool isn’t in use, therefore not needing the pool water to be circulated as much.

Pool pump inverter running costs

Can a pool pump inverter save pool owners on energy usage costs too? Absolutely.

The below calculations shown are based on the following assumptions:

  • The pool pump is 1hp (0.746kW).
  • Output – 1.02kW Input – 73%

The illustrated calculation is based on Clever-Pool operating at the following parameters:

  • 19 hours per day at 1,200rpm pump speed 173.91kWh per month
  • 1 hour per day at 1,700rpm pool pump speed 17.63kWh per month
  • 4 hours per day at 2,100rpm pool pump speed 89.50kWh per month

Figures may differ due to variable parameters, eg cost of kWh of energy, the efficiency of a pool circulation pump, etc. Above figures are based on a 30-day month.

Typical running costs for 1 month (30 days)

  • Energy consumption per month: 732kWh
    Price per kWh of electricity 25p per kWh
  • Monthly expenditure: £183.00

Typical monthly running cost with pump-linked pump inverter

  • Energy consumption per month: 281.03kWh
    Price per kWh of electricity: 25p per kWh
  • Monthly expenditure: £70.25

In short: With a pool pump inverter you can see £112.75 in savings per month.


Handy resources

The below video is from IDS Ltd. The video shows a demo rig of a balloon machine.It shows the effects of using an inverter to control airflow and compares the savings. In this case, it’s demonstrating the centrifugal load on a fan, but this also applies to pumps. It shows a good physical demonstration of what results an inverter can provide.

The technical reasoning behind the energy-saving shown in the video is due to what is known as the “Cube Law”. This law dictates all centrifugal loads. At 100% speed, you use 100% power.

If you then slow down the speed to 80%, you’ll get 80% x 80% x 80% which will work out at 50% of the power used. So, losing 20% of the flow will save you half of the power on use. 


Closing thoughts

At Blue Cube Pools, we offer not only a top-of-the-range VSP but also ongoing preventative maintenance and water treatment services to help keep your pool in perfect shape, all year round.

If you’re not sure what type of pool pump would be best for you, don’t hesitate to contact us today. Our team of friendly and experienced professionals is always happy to help!

Find out more about our pool maintenance services today!