Can I Use a Variable Speed Pump in a Hot Tub?

Variable Speed Pump in Hot Tub

This is one of the questions that I do get asked regularly. There tends to be a common misconception around variable speed pumps and hot tubs. So, hopefully, in this article I can dispel some of the myths around the topic.


I’ll start us off with a statement – you cannot use a variable speed pump for the jets in your hot tub. Why not? Read on and I will explain all.

What is a variable Speed Pump?


A variable speed pool pump is a type of pool pump that allows the speed of the motor to be adjusted to various levels, rather than having a single fixed speed like a traditional single-speed pool pump.


The motor in a variable speed pump is typically controlled by a digital controller that allows the pump to operate at different speeds based on the pool’s needs.


There are several advantages of a variable speed pool pump over traditional single-speed pool pumps:


  1. Energy efficiency: Variable speed pool pumps are much more energy-efficient than single-speed pumps because they can adjust their motor speed to match the pool’s needs. By reducing the speed of the motor, the pump uses less electricity, resulting in significant energy savings. According to the US Department of Energy, variable speed pool pumps can save up to 90% on energy costs compared to traditional single-speed pumps.


  1. Reduced noise: Variable speed pool pumps operate at lower speeds, which makes them much quieter than traditional single-speed pumps. This is especially beneficial if the pump is located close to the pool or in a residential area where noise pollution is a concern.
  2. Longer lifespan: Because variable speed pool pumps operate at lower speeds, they experience less wear and tear on their motor and other components. This can result in a longer lifespan for the pump, which can save money in the long run.
  3. Better water quality: Variable speed pool pumps can run for longer periods of time at lower speeds, which allows for better circulation and filtration of the pool water. This can result in better water quality and fewer chemicals needed to maintain the pool.
  4. More control: Digital controllers on variable speed pool pumps allow for more precise control over the pump’s speed and operation. This means that pool owners can adjust the pump to match the pool’s needs, whether it’s for regular circulation, cleaning, or heating.

In summary, variable speed pool pumps offer several advantages over traditional single-speed pool pumps, including energy efficiency, reduced noise, longer lifespan, better water quality, and more control. They can result in significant cost savings and improved pool maintenance for pool owners.


Is a Variable Speed Pump the same thing as a Dual Speed Pump?


A variable speed pump and a dual-speed hot tub pump are not the same thing, even though they both have the ability to change speeds.

A variable speed pump is a pump with a motor that can adjust its speed continuously over a range of speeds, whereas a dual-speed hot tub pump is a pump with two fixed speeds: low and high. In other words, a variable speed pump can operate at any speed within a specified range, while a dual-speed pump can only operate at two specific speeds.

The main advantage of a variable speed pump is that it can adjust its speed to match the needs of the pool, resulting in energy savings and improved performance. A variable speed pump can operate at a lower speed when less flow is needed, such as during periods of low pool usage, and can ramp up to a higher speed when more flow is required, such as during periods of high pool or spa usage or when additional water features are turned on.

On the other hand, a dual-speed pump is limited to only two speeds: low and high. The low speed is typically used for filtration, while the high speed is used for other functions, such as powering water features or jets. However, because a dual-speed pump is limited to these two speeds, it may not be as energy-efficient as a variable speed pump.

In a hot tub, a dual-speed pump may be suitable for some applications, as it can provide enough flow for filtration and power the jets on high speed. This allows you to to operate your hot tub with just one pump.


While both a variable speed pump and a dual-speed hot tub pump can change speeds, they are not the same thing.


Why is a Variable Speed Pump not suitable for a hot tub?


A variable speed pump is not suitable for a hot tub as the spa pack controller that controls the pumps and blower is not able to change the speed of a variable speed pump.


As a variable speed pump is controlled digitally, the spa pack, which in its most basic form is just a set of relays, it just not able to cope with this.


The spa pack is looking to turn relays on or off. On a dual speed pump, it is either looking to turn on the low speed or the high speed. The state is either on or off if that makes sense – it is not looking to “set a speed”.


Therefore, if you connect a variable speed pump to a hot tub spa pack, it will be either turned on or off – the variable side of things cannot be controlled by the spa pack making it somewhat redundant.


Given the cost of variable speed pumps which can be 5x or 6x the cost of the hot tub equivalent, it just does not make sense to put one on a spa pack when the feature set becomes redundant.


Even using one of these for filtration, heat and circulation is an overkill. It is just much simpler and easier to run a hot tub circulation pump.


Also, given the fact that the pump is not running 24/7 like it will be in most pool applications, there is not the savings to be made on the running costs of a hot tub setup as there are with a variable speed pump in a pool setting.


Bottom line – there are cheaper hot tub pumps out there that will do the job on a hot tub better than a variable speed pool pump will. A hot tub spa pack is looking to turn a pump on or off, whether that is a single speed pump or a dual speed pump. It is not looking to set a speed digitally which is what a variable speed pump can do.

I’ll finish with a comparison. Trying to fit a variable speed pump to a hot tub is like trying to put a battery in your wind up watch – it is just not needed nor is it compatible.

Happy Hot Tubbin’


Can I Help You?

If I can help you in any way I would love to hear from you. You can get in touch using the form below.

Thanks - Andi


Hi, Andi here. I own and also write all of the articles and info pages on the site. Some years back now, I built my own hot tub but struggled to find the information I needed. So, once my tub was complete, I started this website to help others in their own pursuit of hot tub and plunge pools DIY building information.

Today, I've helped over 1000 DIY customers just like you all over the world build hot tubs and pools. Have a good look around the site, there are lots of resources here. Please do get in touch if I can help you. - Cheers, Andi

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