What Is the Minimum Temperature for a Hot Tub?
By Jennifer Rhodes · Updated
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There are a few reasons why you might be wondering how low your spa can go: maybe you want to know what a comfortable temperature is for regular use, or perhaps you're not sure how cold your hot tub should get while you're not using it over the winter.
The minimum desirable temperature for a spa can depend on a number of factors including season or climate, personal preference, budget and safety. Let's dive into what this means for several potential situations.
What is the minimum comfortable temperature for use?
Most manufacturers recommend setting your hot tub to maintain a balmy 100°F the majority of the time. This strikes a balance between usable temperature and energy efficiency.
However, the majority of hot tub users prefer water temperature in the 100°F-102°F range, so you might have to crank it up a degree or two when you want to use the spa.
What you consider a comfortable minimum temperature will also depend on your climate, of course. So on a hot summer's day in Texas, you'll want much cooler water than if you were hot tubbing in the snow in the middle of winter in Toronto.
If you’re not sure what's comfortable for you, experiment by setting your spa at body temperature (98.6°F or 37°C) initially. Then if that feels too cold, increase the heat in gradual increments until you find your comfort zone.
It's also worth noting that the CDC recommends a maximum of 104°F. You shouldn't need to leave your tub this warm all the time, but it's useful to know to help you avoid potential health risks.
Hot tub temperature for children
Kids have a lower tolerance for hot temperatures. In fact, children under age 5 should not be in hot tubs over 95°F, and should only remain in hot tubs for 5-10 minutes at a time.
So, if you have kids or grandkids, know that the comfortable minimum for them may be significantly cooler than what it would be for you.
What is the best temperature for a hot tub in summer?
Summer can actually be the perfect time to enjoy a refreshing soak in a hot tub, but what's the best temperature to set it at?
Typically, a temperature range between 82-86°F (28-30°C) is considered comfortable and refreshing, especially on warmer summer days.
But remember, everyone is different. If you're worried about getting too hot, the key is to start with a lower temperature and gradually increase it until it feels right for you. After all, nobody wants to overheat and become dehydrated or dizzy.
So, whether you're looking for a relaxing soak or a revitalizing escape from the summer heat, finding the right hot tub temperature is key. I will share more tips on how to get your spa even cooler later on in this article.
What temperature should I set my hot tub when on vacation?
When you're away from home, you can set your spa to maintain a lower temperature, which can save energy and money.
If you're just going away for a few weeks, most hot tubs have a setting designed for exactly this. It will maintain the temperature at around 15 degrees lower than normal, and is often called something like or 'economy' or 'sleep' mode—so look out for this in your manual.
When you get back from your trip, simply set the spa back to standard mode, and it'll heat back up to your regular temperature.
How cold is too cold for a hot tub?
If you live in a colder climate and experience freezing winter temperatures, you'll need to decide whether you want to use your hot tub throughout the winter months.
If you don't plan to use it over this extended period—or at least not enough for it to be worth the elevated electricity costs—consider winterizing it.
You should never let your hot tub freeze, as this can burst pipes and damage equipment. Instead, winterize it properly by draining and cleaning the spa, then remove all water from the pipes before leaving it off over winter.
Can you use a hot tub with cold water?
Most hot tubs will typically go as low as 80 degrees, which essentially turns the heater off. So if you live in tropical or desert climate, it's totally okay to turn the temperature down as low as it will go.
Alternatively, if your spa has separate heater and circulation controls, you can turn off the heater completely. This should be fine as long as your ambient temperature remains above freezing.
Just remember that hot tubs need to keep the water circulating regularly to avoid becoming stagnant, which can allow bacteria to grow.
But what if you want even colder water?
What if your hot tub temperature won't go down low enough?
In warm climates, it can be challenging to maintain a low hot tub temperature because the water will tend to warm up to the surrounding air temperature no matter what you do. The higher the ambient temperature, the harder it becomes to keep your hot tub water cool.
You have a few options to deal with this problem:
1. Cool down your spa temporarily
If 80°F isn't cold enough, you can always top up the spa with cold water from the hose, or even add some ice for an instant fix on a very hot day.
Just be sure to check and adjust your water balance after though, as introducing new water could change your pH, alkalinity and calcium hardness.
2. Get your spa out of the sun
Moving your hot tub to a more shaded area or using a hot tub umbrella can help to reduce the impact of direct sunlight and lower the temperature of the hot tub. By reducing the amount of heat entering the hot tub, the water temperature will be easier to control and maintain.
A hot tub umbrella great accessory to have on hand. They can be adjusted to provide shade from the sun throughout the day and also protect the hot tub from direct sunlight, preventing fading. Hot tub umbrellas come in various sizes and materials, and can also complement the décor of the hot tub area. See a few of my favorite umbrellas here.
Placing the hot tub in a shaded area under trees or a pergola can also provide effective protection from the sun. If you go this route, it's important to watch for falling leaves or debris, which can clog the filters and impact the hot tub's performance if this stuff makes its way into the water.
3. Invest in a cold water tub
The above solutions work as temporary ways to cool the water a little, but if you want consistently cool water at any time of year, there are tubs designed more specifically for this.
Some spa brands (currently only Caldera and Hot Spring) offer integrated CoolZone™ hot tub cooling systems as an add-on.
Another manufacturer to check out is Atera Spas. Their spas are built with patented cold-to-hot technology, and they also offer dual-zone swim spas if you want a warm hot tub and cool swim spa in one.
With some of these systems, you can get your spa as low as 60 degrees.
How do you balance energy consumption and spa temperature?
Energy usage is a concern for many hot tub owners, both for ecological and financial reasons.
You might think you should lower the temperature of your spa when it's not in use. Less heating means less energy used, right? Unfortunately, this isn't as wise as a decision as you might think.
Turning down the temperature between uses—especially if you take a dip several times a week—can actually increase energy costs.
Did you know? Heating a spa from cold to hot actually puts more strain on the heating system and and consumes more energy than it takes to simply maintain the temperature at a consistent warm level.
That's why 100°F is a perfectly reasonable temperature to leave your spa, whenever it's in relatively frequent use.