Swim spas are perfect for those who want to imitate the open water swimming experience within the comfort of their own home. Many swim spas also accommodate jetted seating which can provide more relaxing hydrotherapy properties.
But because they offer multiple different use cases, some people can find themselves asking “should swim spas be used hot or cold?”. The simple answer is both.
In this article we’ll highlight the best swim spa temperatures for different activities, as well as how to tailor it to your own personal preferences.
The perfect swim spa water temperature varies based on a multitude of different factors. These consist of the activities you wish to use the swim spa for, as well as other external factors like weather and ambient temperature.
If you wish to use your swim spa for recreational swimming we advise that you set the water temperature within the region of 27°-31°C, similar to that of a traditional swimming pool. However, this is purely based on personal preference and you may find a temperature of 32°C to be more comfortable, especially if children are using the swim spa.
Going any higher in temperature than this can pose the risk of overheating and dehydration, so it’s important to monitor yourself and how you feel during and after exercise in order to use your swim spa safely.
How long you plan on exercising for and your preferred intensity level should also help guide you when setting the right temperature for your swim spa.
For example athletes who swim at competition level can have their pools set all the way down to 25°C due to the intense nature of their workouts. So it is always best to stay on the safe side and cool your swim spa appropriately relative to how long and how hard you plan on exercising.
If you want more information on swim spa workout exercises head over to our Top Swim Spa Exercises in 2025.
If you wish to use your swim spa primarily for it’s therapeutic attributes, it may be best to increase the temperature to around 34°C-36°C. This will ensure that you are able to unlock the desired benefits that come with warm water like improved circulation and muscle relaxation.
Going to higher temperatures than this is also beneficial for hydrotherapy, but it means you won’t be able to stay in as long.
The surrounding air temperature is definitely an important factor when determining the appropriate temperature for your swim spa.
Generally speaking, if you are in a warmer climate you may want slightly cooler water, compared to in colder climates where you’ll likely increase the temperature by a couple of degrees. The surrounding ambient temperature does make a difference to the heat retention of your swim spa, as well as how long it takes to heat up to your desired temperature. However, this can also depend on the quality of your swim spa cover & insulation.
There are some other ways of quickly reducing your swim spa temperature like lifting the cover off ahead of time, or using ice or cool water from the hose. But if your in a hot climate and want to cool your swim spa down overnight, feel free to use towels or a thin pool noodle beneath each corner of the spa cover to allow cool night air to circulate beneath.
Inviting family & friends over to your swim spa retreat is a great idea, but bare in mind that this may affect the water temperature.
An increase in bathers using your swim spa at one time will usually lead to an increase in temperature. This means that you may want to lower the water by a degree to ensure that it does not exceed your desired temperature, especially during the summer months.
Even though swim spas can use their heater to warm up the swim spa at any given time, they are not capable of cooling the water down at the push of a button like an ice bath. However, if you decide to fit an air source heat pump to your swim spa, you can extract the heat out of the water at a much faster rate.
This is why it’s important to plan ahead of time if you are having a get-together, as you’ll have to let the temperature cool down naturally or set your heat pump to cool mode.
The average body temperature sits in the region of 37°C (99°F), so any water temperatures below this may start to feel slightly cool. However, if you know your body temperature typically runs higher than 39°C (102°F), we recommend setting your swim spa to a slightly cooler water temperature to counteract this.
If you plan on relaxing in your swim spa like a hot tub, feel free to explore higher temperatures similar to your body temperature. However, for exercise purposes we advise you drop down to the 27°-32°C region dependent on the intensity.
Since 40°C (104°F) is the maximum temperature setting for most swim spas, it’s important to be mindful of how long you stay in. To avoid heat-related risks, we recommend limiting your soak to no longer than 15 minutes at this temperature.
If you’re planning a longer session, it’s best to lower the temperature to a more comfortable 37–38°C (99–100°F) and make sure you stay fully hydrated throughout.
Generally, setting your swim spa water temperature within the 20°C (68°F) region will feel too cold for most users. That said, the ideal temperature really comes down to your own personal preference, the surrounding climate conditions, as well as what activity you wish to use your swim spa for.
Typically, the lowest temperature we see people use their swim spa at is 25°C (77°F), as this mimics the same conditions as Olympic pools during competitive swimming events.
Some people feel that setting their swim spa down to 20°C will offer the same effects as cold water immersion, but typically you won’t see the physiological responses & benefits unless you are in temperatures of 5°C (31°F) to 15°C (59°F). Most swim spas don’t drop to those temperatures, so you may want to consider a cold plunge ice bath if that is desirable.
During summer, it is usually best to lower the temperature of your swim spa by a couple of degrees to prevent overheating. If you are swimming or exercising we generally find the 25-29°C (77-84°F) range to be comfortable enough during the hotter spells.
Because swim spas don’t have integrated chillers, if the water is naturally higher than you would prefer it to be, it may take a little while to lower it. If that is the case, try reducing the temperature of your swim spa by lifting the cover off ahead of time or using ice or cool water from the hose. You can even retrofit an air source heat pump- just switch it to cool mode and watch it pull the heat right out of your spa!
It’s also worth mentioning that installing a gazebo or umbrella over your swim spa can help deter against uncomfortably warm water, as direct sunlight can contribute to the heat.
During winter, it is usually best to increase the temperature of your swim spa by a couple of degrees to help ease the coolness. If you are swimming or exercising we generally find a slightly warmer temperature of 30-32°C (86-90°F) to be most comfortable when breathing in the cold winter air.
However, some users decide against the winter swim spa experience all together, and choose to winterise their swim spa. This is the process of removing all the water, filters and thermal cover to help prevent any freezing or ice damage that can occur in winter climates. This can happen when water expands within the pipes, resulting in leaks, damaged heaters and can sometimes even crack the shell of your swim spa.
Most people tend to winterise their swim spa if they don’t plan on using the swim spa at all through winter. This is because it comes with the added benefit of reduced energy costs, as well as protecting the components of the swim spa.
When your swim spa is not in use, we advise that you lower the temperature down to around 25-29°C (77-84°F), but feel free to lower it further if you don’t plan on using the swim spa for a while.
Swim spas can take between 8 and 24 hours to heat up to temperature. The amount of time it takes varies on a multitude of different factors such as size, starting water temperature, ambient temperature, heater size, insulation & cover variation etc.
If you decide to retrofit an air source heat pump to your swim spa, this can heat the water up much faster depending on the size of the heat pump and its COP value.
If you’re lucky enough to own a a dual-zone swim spa, you’re able to benefit from two different water temperatures at one given time. This means you can effortlessly interchange from one to the other without having to wait for the water to heat up.
Dual-zone swim spas are perfect for those who want the hydrotherapy benefits of a hot tub, as well as having a dedicated swimming area. Being able to seamlessly transition from one to the other is super convenient, and can also offer more socialising opportunities.
Some family members tend to be more enthusiastic about swimming than others, so being able to offer the best of both worlds is great for spending good quality family time together in the swim spa. Whilst one person is lap swimming against the swim jets, the others can sit back and relax in the warmer hot tub side.
About the author
am the content writer & social media manager at WhatSwimSpa? Magazine. I have worked at WhatSwimSpa? for over 2 years now, and I recently graduated with from Northumbria University with a Bachelor's degree in Business Management with Marketing. My role at WhatSwimSpa? is to ensure that all swim spa lovers can easily access the highest quality and most up-to-date content, news and information from within the UK wet leisure industry.
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