Posted by Josh Clamp in
Blog post, Maintaining a Hot Tub Guides
on 7th March 2025
In recent times, hot tubs have become an essential component within our wellness routines.
However, knowing how to find the right hot tub temperature range for you can be a little complicated – too hot and it can negatively affect your health, too cold and you won’t get the maximum benefit from your hot tub.
Read on to find out how you can determine the recommended hot tub temp for you.
Generally most people like to enjoy their hot tub between 36°C and 38°C (97°F – 100°F), but we recommend that it is lowered to around 35°C (95°F) if children will be using the tub. Kids are slightly less tolerant to heat compared to adults, so it is best to ensure that they are under supervision at all times and stay in for no longer than 15 minutes.
If you suffer from any underlying health conditions it may be worth consulting with a medical professional prior to bathing to avoid any heat related health risks.
The average body temperature sits at around 37°C (99°F), so any water temperatures below this can tend to feel a bit chilly. However, if you know that your body naturally exceeds the 39°C (102°F) mark, we advise that you cater for this with a slightly lower temperature when using a hot tub.
It is also worth noting that the water temperature may drop by a few degrees when removing your hot tub cover, so you might want to start at a slightly higher temperature to counteract this.
Given that 40°C (104°F) is the the maximum temperature that you can set most hot tubs to, you need to be careful about staying in there for too long. We advise that you stay in for no longer than 15 minutes at this hot tub water temperature to negate any heat related risks.
So if you fancy a longer dip we suggest that you turn the temperature setting down to a cooler 37-38°C (99-100°F), as well as ensuring that you stay well hydrated.
Generally, setting your hot tub water temperature within the 32-35°C (90-95°F) region will be too cold for most. However, finding the best spa temperature is all based on personal preference – as well as the climate of the atmosphere around you.
During summer, it is typically best to set the temperature of your hot tub to a slightly cooler 35°C – 37°C (95-99°F) to prevent overheating. However, we recommend that you experiment from as low as 29°C (84°F) as hot tubs can be great for cooling off too! This is comparable to the temperature of a typical heated swimming pool.
If you’re short for time and want to get your water to cool down quicker, try dropping the temperature using the control panel. You can also activate the main pumps and water jets with the air controls open and the air blower (if your tub has one) for maximum air flow through the water.
During winter, it is typically best to set your average hot tub temperature within the 37°C – 40°C (99-104°F) region to keep you warm as well as preventing any risk of freezing. The winter months can make for the best time to use your spa as you descend into the warm water whilst breathing in that fresh cold air.
However, some users decide against the winter hot tub experience and in these cases it may be best to winterise your hot tub to prevent any freezing and ice damage. This can occur when water expands within the pipes and can ultimately result in leaks, damaged heaters and even cracked shells.
During pregnancy, your body increases blood supply to the skin, making it more difficult to lose heat effectively from your body. Therefore, we advise that most women avoid using the tub to prevent any chance of deregulation in body temperature.
If you do decide on using a hot tub whilst pregnant, we recommend heating your tub to a maximum temperature of 37°C (99°F) to help mitigate any heat related health risks. It is also important to take precautionary measures to avoid prolonged exposure (no longer than 10 minutes).
To get more information on safety advice for pregnant women head over to our dedicated blog Can You Go In A Hot Tub When Pregnant?
If you decide against using your hot tub for a while, we suggest not turning it off and to keep it at a temperature of around 30°C (86°F). This will help conserve energy as well as being more cost-effective when it comes to heating the tub back up again.
If you plan on staying away for a more extended period of time, it may be worth lowering it to an ambient temperature of around 10°C (50°F), or the minimum set temperature that your control panel allows, in order to reduce energy costs.
If rising energy tariffs are a major concern for you, it may be worth checking if your spa is air source heat pump compatible. To read more about how heat pumps can increase your energy efficiency, take a dive into our dedicated Ultimate 2025 Guide.
This depends on several factors, such as the size of the heater in kW, the total volume of water, and how well insulated the hot tub is. Typically, a hard-wired hot tub with a 3kW heater and around 1,500 litres of water will get around 2°C hotter each hour until it reaches the set temperature.
This means that your hot tub will take roughly take between 6 and 15 hours to heat up after it’s been filled, depending on the ambient temperature of your source water. Source water temperature can vary from below 10°C in winter to almost 20°C in the height of summer in the UK.
If this feels like a long wait, many hot tubs now come with smart device compatibility, allowing you to heat your tub remotely. This means you can adjust your hot tub temperature settings before you even get home. You could also fit an air source heat pump which will heat up the water much faster than a standard heater.
It is worth noting that the temperature outside will also play a factor in how quickly your spa heats up, so you’ll have to wait longer to enjoy a soak during a snowstorm in comparison to a heat wave.
To get more information on how you can heat your hot tub up faster, dive into our dedicated blog How long does it take to heat a hot tub.
If you are specifically wanting to use your hot tub to unlock the maximum hydrotherapy benefits, we advise that you keep it to a minimum temperature of around 37°C (99°F). This is the ideal temperature for loosening those tight muscles as well as relieving any aches and pains.
However, don’t worry if you prefer cooler hot tub water as there is still plenty of perks in hydrotherapy within all temperature ranges.
If you’re planning on using a hot tub primarily for the social interaction, we advise that you maintain a safe hot tub temperature of around 37°C (99°F).
We all know how fast time can fly when you’re catching up with loved ones, so keeping it at a moderate heat level is perfect for staying in the tub for extended periods of time.
However, it is recommended that you keep this to a maximum of around 45 minutes within this temperature range as staying in any longer increases the risks of overheating.
Also bear in mind that plug and play 13amp hot tubs cannot run the heater at the same time as the main hydrotherapy pump on full speed, so the water can cool down quickly with the hydrotherapy jets on full power.
The simple answer to the question “what is the recommended hot tub temperature?” is 37°C – 40°C (99-104°F), but personal preference and other health factors may influence this. If you enjoy hot water whilst taking a bath or shower, generally your perfect hot tub temperature will coincide with this.
BISHTA (The British and Irish Spa and Hot Tub Association) state that the maximum safe hot tub temperature is 40°C (104°F) and bathing in water any higher can pose serious health risks.
About the author
I am the content writer & social media manager at WhatSpa? Magazine. I have worked at WhatSpa? 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 WhatSpa? is to ensure that all hot tub 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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