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What Temperature Should You Keep a Hot Tub When Not in Use?

The cost of owning a hot tub can add up. So naturally, people like to find ways to shave a bit off the electricity bill. If that’s you, you’ve probably wondered what temperature should you keep a hot tub when not in use?

As a general rule, a hot tub should be set between 98 and 104 degrees Farenheit even if not in use. For vacations lasting between 2 and 6 weeks, lower the temperature by 5 degrees. Beyond 6 weeks, consider powering down and draining.

The cost of reheating each time can be greater than maintaining a consistent temperature. And the cost-saving from setting a lower temperature is usually small.

Why a range of 98°-104°? It’s really just a matter of personal preference. 104 is the max temperature to safely soak in. But at 98, you can soak a lot longer.

The hot tub should not be turned off even when not in use for a week or 2. Strange? In this article, you’ll discover why it’s perfectly logical and some exceptions to the rule.

We’ll be exploring issues around the most economical way to use your hot tub. And there is 1 set of circumstances where it does make sense to simply turn the power off.

Let’s dive right in…

temp not in use 2 lg

Should I leave my hot tub on all the time?

A hot tub should be on all the time except when it is not going to be used for 2 or more months. For extended periods of inactivity, it is best to cut the power and drain the hot tub. Otherwise, a hot tub should be on all the time.

Of course, it should be turned off when it is time for repairs or maintenance.

I understand that it might feel as if you’re wasting electricity if it is on all the time and that you’d have to pay a lot more. But, this is not the case. I’ll explain.

The reality is that you’ll pay more for electricity if you were turning it on and off after each use!

It consumes more energy each time it’s started, and you’re waiting for it to get to the right temperature than what it needs to keep itself running.

Apart from the cost, there’s also the delay, as you’ll have to wait each time as the water gets reheated before you can use it. Another good reason why it shouldn’t be turned off is that its circulation system can’t function when it’s off.

And, this system is one of the vital processes that help keep the water safe.

If the hot tub is off, it’s likely to quickly become a breeding ground for harmful disease-causing microorganisms.

If you’re using it once or twice a week, it should be left on. But, if you won’t use it for a month or months at a time, then it’s okay to turn it off.

This question of leaving the hot tub on even when it’s not being used is the subject of a recent article of mine where I went into more details. I even get into the scenario where it’s okay to simply cut the power and leave it alone.

Just click the link to read it on my site.

Does turning down hot tub save money?

Turning down a hot tub and then turning it back up to use it will not save money. It takes more electricity to reheat the water than it does to maintain it. However, permanently lowering the set temp will save between $3-$10 per month on energy costs.

It’s actually when the water is being heated up that a lot of power is being consumed. And, that’s what significantly increases what you’ll have to pay.

Once it’s heated up, it doesn’t require much power.

Turning it down and up, again and again, is more expensive in the long run because each time you have to heat it up again, more power would be consumed!

And, this heating-up process could take up to 1 to 2 hours depending on your model, considering that hot tubs heat between 3-6° per hour.

To get it up to a temperature of 100° F (37.78° C) would be more expensive than simply leaving it at that temperature. So as odd as it sounds, leave it set where you like it for maximum energy efficiency.

So, turning it down would only help you save a small amount of money. I suspect you’ll want to find out how much electricity does an average hot tub use each month.

Luckily, that’s what I explored in a recent article of mine where I showed that about $30 is the monthly average for mist hot tub owners. However, there is 1 circumstance where I’ve heard of people paying 10 times that!

Just click the link to read it on my site.

It is ideal to keep your hot tub running, even if it’s in sleep or economy mode because its circulation system ought to be functioning even when it’s not in use.

The water must be circulating, as stagnant water can easily become host to bacteria and viruses!

What is the most economical way to run a hot tub?

The most economical way to run a hot tub is by setting the temperature below 100° F (37.78° C), using a floating thermal blanket, keeping the cover fully closed when not in use, and setting heating and filtration cycles during off-peak hours.

These cost-saving strategies fall into two groups: one is focused on saving energy cost, while the other is on regular maintenance.

It’s not ideal to turn a hot tub on and off frequently.

To reduce power consumption, the best way is to add extra insulation under the shell and behind removable panels. But you can also use a floating thermal blanket that also serves as a solar cover. This floats on the surface of the water just under the hot tub cover.

Just remove it before using (obviously).

My favorite thermal blanket on Amazon is under $50 bucks, can be cut to size, and is an Amazon’s Choice product with well over 100 near-perfect reviews.

It’s vital to also set it at the right temperature, which depends on how often you use it, to take advantage of off-peak rates to reduce your energy bills.

What are off-peak hours?

These are the hours of the day where your electricity provider charges lower rates as they are often low-use times. They could be late morning and late evening. But check with your provider to be certain.

Not sure how to use a thermal blanket or how much it can save on your electric bill?

Luckily, I get into all that and more in a recent article. Just click that link to read it on my site.

What do you do with a hot tub when you go on vacation?

For quick trips of 1 week or less, a hot tub requires no changes. For vacations of 2-4 weeks, consider lowering the temperature by 5 degrees and adding a double dose of shock before leaving. For trips well over 1 month, it may be worth considering powering down and draining.

But really, that’s not necessary.

It will just save a little money on your electric bill. But you may lose that savings on your water bill when you fill it back up again unless it was time for a water change anyway.

If you’re just going to be away for 2-4 weeks, make sure you do the following:

  • Test and balance the water
  • Add a double dose of hot tub shock
  • Rinse the filters
  • Lower the temp 5 degrees
  • Secure the hot tub’s lid

And, of course, you could always hire a pool company to do routine maintenance on it while you’re gone too.

If you’re going to be away for 4-6 weeks or longer, it may better to drain the water, clean it, and thoroughly wipe down the hot tub so that it’s dry.

You don’t want to leave any water in it.

Any standing water could serve as a breeding ground for germs. Make sure you use a powerful cleaner before you drain it so that you can get rid of the gunk and biofilm.

The best product to get rid of the bacteria build-up in your pipes known as biofilm is Oh Yuk! Healthy Hot Tub Cleaner on Amazon.

Just pour it in before draining. Run the jets for 1 hour (restarting as needed), and then drain, clean, and refill as needed. I do this every time I drain mine.

For any standing water left after draining, you can even use a wet/dry vac to ensure there’s no water left in the lines.

You don’t want the plumbing to freeze or some microorganisms starting a family in the pipes. Leave the drain plugs off and make sure to cover the hot tub.

If you’ll be gone for a very long time and winter is near. It’s better to have it winterized.

Not sure what that entails if antifreeze can be used or when winterizing isn’t necessary? Luckily, I have a recent article that covers all of that.

Just click that link to read it on my site.

If I won’t use it for months, should I drain my hot tub?

A hot tub should be drained if it will not be used for months as it will be adding wear and tear to the equipment unnecessarily and because it would be a waste of money to keep adding chemicals to keep the water clean. And without chemicals, it will become a breeding ground for harmful microorganisms.

In short, the hot tub water would become smelly, slimy, and discolored and could gradually corrode the hot tub equipment.

If a hot tub won’t be used for months, it’s best to power down, drain the water, clean it properly, and wipe it dry.

The pipes should also be cleaned and dried so that germs do not breed there and to ensure they do not freeze (if it’s during a cold period). Depending on the period, it might be a good idea to have it winterized.

Yes, a hot tub that won’t be used for some time should be thoroughly drained and covered.

What if it’s being used, how often should the water be changed?

Interestingly, that’s the subject of a recent article of mine, where I did a deep dive into why the water must be changed and how often you’ve got to do it.

Just click the link to read it on my site.

What is the perfect temperature for a hot tub?

The maximum temperature for safely soaking in a hot tub is 104° according to the CDC (Center for Disease Control). (source)

That being said, you can only safely soak at that temperature for 15 minutes. And even then, that temperature is only recommended for healthy adults.

And if you’re drinking alcohol in the hot tub or not drinking enough water, even 15 minutes can be too much and you can become dehydrated.

So many people find the ideal hot tub temperature to be around 98°. 

That is safer if your kids use the hot tub too. And it allows for longer safe soak times. And in warmer months, it’s also a lot more comfortable.

Then crank up the temperature of the water some as the winter months and cold weather approaches. How much you crank it up will depend on your personal preference and whether you live somewhere with a really cold climate.

Warmer water will feel great in the cold air.

Different temperatures allow for different lengths of soak times. And the outside weather can also affect what your personal preference is on your hot tub’s temperature.

What is the best hot tub temperature for a heart condition?

If you have a heart condition or other medical conditions, always consult with your doctor before ever getting in a hot tub. Warm water and higher temperatures can have a definite impact on a number of bodily functions that can be critical for those with heart issues.

That being said, here’s what cardiologist Curtis Rimmerman, MD. had to say:

“Hot tubs and saunas are potentially dangerous for patients with known or suspected heart disease. However, awareness and common sense can help keep you safe while you soak”

He did, however, indicate that soaks of 5-10 minutes at a lower temperature can work just fine. Just set a timer, and drink plenty of water. And maybe have a friend or family member assist with getting out as a drop in blood pressure or dizziness is a possibility.

What is the best hot tub temperature for pregnant women?

As with any medical condition, hot water poses potential health risks for woman who are or may be pregnant using a hot tub. So always consult your doctor before getting in.

The average normal body temperature is 98.6°. So if your doctor says soaking is OK, avoid setting the spa temperature above that.

The website AmericanPregnancy says “Some studies have shown an increased risk of birth defects in babies of women who had an increased body temperature during the first trimester of pregnancy.”

The American College of Obstetricians and Gynecologists (ACOG) goes on to state that pregnant women need to avoid becoming overheated and to not let the body’s core temperature go above 102.2º F. (source)

So after consulting with your doctor, in most cases, a soak of 5-10 minutes at a comfortable temperature of about 98°.


In this article, we looked at issues around the most economical way to own a hot tub.

We got started exploring the ideal temperature for when it’s not in use. Then, we checked out if it’s okay to leave it on all the time and whether turning it down saved money.

Then we explored the most economical way to use a hot tub and what to do when you are gone on vacation. Lastly, we checked out if you’ve got to drain it if you won’t be using it for some time.

Ultimately it is totally possible to save money on your energy bills while also having your hot tub ready when you are ready for your next hot tub experience.

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Jeff Campbell