Minimum Temperature for Hot Tub in Summer

The summer season can vary across North America, and different states in the US have raised the mercury to different degrees. For hot tub owners, the water heating bill doesn’t make sense when their tap water is as warm as their hot tub. If you’re in a similar situation, you might wonder whether you can turn off your hot tub.

The minimum temperature for a hot tub is 85°F, while 90°F is considered a comfy starting temperature. If your tub water is over 85°F without heating, you can turn off your water heater. If you use ice to chill your hot tub, you need to use pool chemicals to keep the tub microbe-free.

In this article, you will learn more about using your hot tub as a cold tub as well as using your hot tub as an average temperature spa. You will discover the best practices of having a cold tub in the summer and keeping your tub lukewarm alongside the pros and cons of each. Let’s get into it.

How Low Can You Keep a Hot Tub in the Summer?

You can keep the hot tub at 85°F in the summer. If the water reaches this temperature naturally, you don’t need to run your tub’s water heater during summers. But for this, you have to be sure that the water will not go any lower than 85°F throughout the summer.

More importantly, you must make sure the water keeps circulating. Without circulation, even warm water stagnates, which is why tropical countries with poor hygiene have mosquito problems. Circulation without heating is possible in most modern hot tubs, so it shouldn’t be a problem.

All in all, you can turn off your hot tub during the summer if the water in it stays at around 85°F. If it fluctuates, you might have to run your water heater for 2 to 4 hours every day. Even if the water stays at 85°F throughout the season, there can be minor hygiene issues if the water stays in one spot. Circulating the water by running the filter pump for 4 to 6 hours is advisable.

What To Do With a Hot Tub in Summer?

While the above is one way to handle your hot tub in the summer, there are actually three things you can do with your hot tub in the warmer portion of the year.

  1. Option one: Turn off the heating but circulate the water for 4 hours every day. 
  2. Option two: Drain the hot tub and avoid using it 
  3. Option three: use pool chemicals and ice to make your hot tub a cold tub

Each of these options has its respective pros and cons. A hot tub that is kept hot during the summers is barely usable. But some people enjoy an average-temperature dip. If you’re one of them, then it makes perfect sense to just turn off the water heater and enjoy the jets.

The second option is the least fun but also has the lowest responsibility. When your hot tub becomes an empty tub, you don’t have to worry about pool chemicals, heating, and temperature maintenance. However, you can’t really use the tub when it doesn’t have water. If you travel for the summers, this is an ideal option.

The third way to manage your hot tub during the summer is the most fun. You can add ice blocks to your hot tub after its heating is switched off. This can make your tub dip-ready for a chilled bath. 

If you get too hot during the summers and want to cool off in your “hot tub” or simply love the irony of having a super cold hot tub, you can go with this option. You just need to remember that the burden of killing microbes with heat gets transferred to pool chemicals. You need more shock and have to check the tub chemistry more often.

Can You Keep a Hot Tub Cold in Summer?

You can keep a hot tub cold in the summer only if you use pool chemicals and water circulation to keep the water free of microbes. It is advisable to avoid freezing water as it can be injurious to health. 70°F is the recommended temperature for cold baths.

What Temperature Is Too Low for a Hot Tub?

A hot tub can accommodate any degree of cold water as long as it is not frozen. But for the human body, baths at temperatures below 70°F can have adverse effects. For prolonged chilled baths, you can put ice in the hot tub until it reaches 70°F.

Microbes can thrive at this temperature, so you need to be very serious about water circulation (running the pump for 8 hours) and pool chemicals. By adding chemicals that kill harmful bacteria, you can ensure that the lack of heat doesn’t promote infestation.

If you find 70°F to be too mild, you must note that cold water drains the body of water 20 times faster than cold air. So 70-degree water feels colder than a 70°F atmosphere. If you’re into ice baths, then the temperature recommendations will be atypical, but that’s not what most people want from a chilled bath during a hot summer evening.

What Temperature Should I Set My Hot Tub in Summer?

You can set your hot tub at 85°F if the summer weather doesn’t naturally bring the water temperature beyond 85°F. If the water temperature is naturally higher than 90°F, you can simply turn off your hot tub’s water heater. You’ll still need to circulate the water to keep it fresh.

The temperature at which you set your hot tub depends on your goals. As mentioned earlier, there are three options. Here they are categorized by goals.

GoalRecommended Hot Tub TemperatureRationale
Lower the energy bill85°F  You can achieve this by turning off your hot tub water heater during the summer
Keep the hot tub usable during the summers75°FYou can enjoy a cool bath at this temperature. The water heater needs to be turned off, and you need to use ice.
Stop having to worry about the hot tubDrain the tubYou can forget about your hot tub if it is free of water and secured by a tub cover.

Final Thoughts

Hot tubs can be fun during cold times. But during the summers, they can be unusable energy bill liabilities. Fortunately, you have multiple options ranging from turning off water heating to using ice to chill your tub. Your hot tub doesn’t have to be a waste of space during the summers.

Jed Arnold

Jed spent every year from the ages of 15 - 22 as a Lifeguard (Red Cross) and ages of 17 - 22 as a Certified Pool Operator (CPO). Between working for over a dozen facilities and owning a pool, he carries over a decade of pool experience.

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