What Temperature Should I Leave My Hot Tub On Overnight?

What Temperature Should I Leave My Hot Tub On Overnight?

Water temperature has a great impact on the overall hot tub experience. It is the hotness in the winter and coldness in the summer that allows you to enjoy a refreshing soak throughout the year. People who use the hot tub very frequently have a wondering of if they can leave their hot tub on overnight and if that is so then what should be the temperature? Because it is a lengthy process to bring your hot tub water temperature to your desired level each day, all over again.

The answer to people wondering is, you can leave your hot tub on overnight keeping the temperature between 95°-104°F in the winter and 90°-95°F for summer. Read till the end to enjoy related informative topics such as reasons to keep the tub on, highest and lowest hot tub temperatures, negative impacts of using too temperature hot tub water, etc. We have also covered some of the probable times when you should consider leaving your hot tub switched off. So start reading to maintain a hot tub inexpensively.

Key Takeaways

  • Water temperature to leave your hot tub overnight varies depending on season and use frequency.
  • For ‘not so frequent’ use, It’s best to lower the temperature by 10°F (5°C) than the usual requirement.
  • Soaking in too much hot water (more than 104°F) can cause mild to severe health issues.
  • It can take up to one hour to heat tubs water 5°F higher.

What Temperature Should I Leave My Hot Tub On Overnight?

What Temperature Should I Leave My Hot Tub On Overnight
What Temperature Should I Leave My Hot Tub On Overnight

The temperature of the hot tub water is very important for both, having a blissful soaking and keeping the hot tub less malfunction-prone. To leave your hot tub overnight you should consider different scenarios such as season of the year, using frequency, etc. Let’s dig deep into each of them:

Hot Tub Temperature: If Used Frequently

If you use your hot tub daily or a regular intervals, then it is advised to keep your hot tub on overnight. But while doing so, the temperature of the hot tub shouldn’t be the same in all seasons.

  • Winter Time: Hot tubs are frequently used in the winter seasons. If you use your hot tub on a daily basis, then it is better to leave the tub on overnight at a temperature of 95°-104° Fahrenheit. This way the tub’s water should be warm enough to start soaking over again the next morning. If you have an outdoor hot tub, then it should be well-covered to ensure better insulation. Note that, in the winter the tub’s water temperature should be more than your body temperature (98.6° Fahrenheit). So keeping the hot tub water’s temperature close to the body temperature will likely prevent it from freezing and less ready time for a fresh soaking.
  • Summer Time: A lot of people use their hot tub even in the summer to have a cooler soaking. For that, you can use your hot tub heater to keep the water cold enough. Some hot tub has cold mode which can keep the water temperature as low as 60°F. For using your hot tub in the summer, you can simply set the water temperature to 90°-95° Fahrenheit and keep the tub on overnight. This will ensure cooler water than your body temperature and you can further cool it if needed when in use.

Hot Tub Temperature: If Not In Use

If you don’t use your hot tub regularly then It’s best to lower the temperature by 10°F (5°C) than the usual requirement. This way you can save a lot of energy bills and keep the hot tub functional at the same time. This means, in the winter a ‘not so frequent’ hot tub should be programmed to keep between 90°-95° Fahrenheit. For summer use, the water temperature should be left close to idle mode. This way, the water treatment process will still be on and keep the water temperature close to your requirement when in use again too.

Is It A Good Idea to Keep Your Hot Tub on Overnight?

Is It A Good Idea To Keep Your Hot Tub On Overnight
Is It A Good Idea To Keep Your Hot Tub On Overnight

It may seem surprising to you that we are advising you to keep the tub on even if not in use daily, but it is actually the most viable and efficient option for you. A good hot tub heats up at a rate of 11°F (6°C) per hour. So based on your tub’s water capacity and current water temperature, heating a hot tub to the desired temperature can take up to 3 to 8 hours or even more. Some benefits of keeping the hot tub on overnight:

1. Lower Operation Expenses

Hot Tubs consume a lot of electricity to heat up the water. Their hunger goes skyrocketing when you start heating your tubs with normal water very quickly. A hot tub with a 120-volt heater will consume 3,000 watts while in use, and one with a larger heater will consume 7,500 watts. That’s 3 kWh and 7.5 kWh respectively. Running the hot tub at shallow capacity will not only ensure the water temperature is close to required but also keep the electricity bill low.

2. Maintaining Cleaner Water

Keeping a hot tub water on overnight means keeping the water treatment on too. Long-time water shocking dispatches more oxygen into the water thus keeping it healthier to use. Also, it is water’s common characteristic that undiluted materials such as water cleaning chemicals, and dirt can form a layer of residue if left without shocking. Keeping the tub prevents all of these from happening.

3. Prevents Bacteria Growth

It is normal for the bacteria to grow in left-out water. Leaving a hot tub at a mild temperature can prevent germs, bacteria, and any other harmful organisms from growing in the water. This way you can avail of bacteria-free water the next day you soak.

4. Stops Water Freezing

In many states, it is not uncommon that water gets freezing cold overnight. This happens because the outside surface temperature is optimal for freezing normal-temperature water. Keeping your hot tub on prevents this from happening as it keeps the water temperature far from the freezing point.

5. Demotivates Hot Tub Use

Keeping your hot tub on overnight influences you to use it more frequently. Switching your hot tub off causes the water to get cold on a winter day. So when the next use schedule comes, you may find it annoying to prepare the water again for soaking. A big hot tub can hold more than 800 gallons of water and it can take forever to heat this amount of water from scratch. This can influence you not to use the hot tub again.

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Too High Or Too Low Temperature In A Hot Tub

Hot tubs are for having hot water soaking. They can also be used as cold soaking in the scorching summer. There is a peculiar temperature difference between these two uses.

The ideal hot tub temperature is between 98° to 104° Fahrenheit. Not that while the minimum temperature is further reducible but the maximum temperature should never cross the 104° mark. Because it will be too hot for the human body and can even lead to damaging the hot tub.

For the lowest temperature part, many hot tubs are equipped to lower the water temperature as low as 60°F. But under ideal circumstances, you should keep the temperature 80°F to 90°F using economy or summer mode.

Negative Impacts Of Hot Tubs Water Being Too Hot

Soaking in too much hot tub water can cause temporary to severe health issues. Some of such negative impacts of hot tub water being too hot are:

Negative Impacts Of Hot Tubs Water Being Too Hot
Negative Impacts Of Hot Tubs Water Being Too Hot
  • Dehydration: Hot tubs and spas can cause you to sweat a lot. You may not feel it in real-time but this sweating can make your body dehydrated as it loses a lot of water. These can have several side effects such as dizziness, thirst, and sickness. That’s why drinking a lot of water is suggested while having a hot tub session.
  • Skin Injuries: If the hot tub’s water is very hot then it can even cause skin injuries. Your skin may feel itchy and irritated caused by the hot water burn. Those who have sensitive skin types can also lead to slight skin burning.
  • Low Blood Pressure: Heat causes the blood vessels in the skin to dilate. As a result, the resistance by the wall of the vessels to blood flow lowers, and the blood pressure drops. In the worst sceneries, this can cause a person to faint and it will be the last thing you want to face in a hot tub.
  • Pregnancy Risk: Professionals advises pregnant person not to use hot tubs as moderate to excess level water temperature can cause harm to the mother as well as the child’s body elements.

When Should You Consider To Power Off Your Hot Tub?

When Should You Consider To Power Off Your Hot Tub?
When Should You Consider To Power Off Your Hot Tub?

Although leaving your hot tub on overnight is good in many ways it shouldn’t be a good decision in all cases. Here are a few considerable moments when you should power off your hot tub:

  • Draining & Refilling: You may need to drain and refill your hot tub for many reasons. Remember to power off the hot tub while doing so. There is no need to run the machine when there is no water in the tub.
  • Long-Time Storage: If you are thinking of storing your hot tub for the summer or some other reason then you should keep the hot tub turned off. Long-term storage means, storing the hot tub completely for 4/5 months or even more.
  • Going For Vacation: It is not uncommon for people to go on vacation for months. Many people tend to leave their houses to enjoy the summer to cooler atmosphere and vice versa. You should switch off and drain your hot tub before leaving.
  • Routine Cleaning: You should thoroughly clean your hot tub at least once every month. This includes draining the older water, switching off the tub, cleaning it, and refilling it with newer water.


1. Can covering keep the water in the tub warm?

Definitely, keeping your hot tub covered can keep the water heated for 18-20 hours. Your hot tub should come with a cover or you can use bubble thermal blankets for this purpose. Though, your tub will still lose some temperature but majority of the heat will remain in the tub.

2. Do hot tubs use a lot of electricity?

Based on your type of hot tub, it will consume 3 kilowatts to 7.5 kilowatts of electricity per hour. By considering 23 cents per kilowatt, it can cost you 1-2 dollars per day to run the hot tub for a moderate time. So, the hot tubs can be considered as an electricity-consuming element.

3. What is the safest lowest temp for a hot tub?

Hot tubs can process and accommodate water as low as 60°F but they aren’t suitable for soaking for long even in the summer. By comparing it to a human’s natural body temperature (98.6°F). 90°F-92°F is the safest and lowest temperature for a hot tub.

Final Thoughts

Although it is tough to determine the exact temperature to leave your hot tub on overnight, generally the range is between 95°-104°F in the winter and 90°-95°F for summer. When not using the tub frequently the formula is to reduce the temperature by 10°F (5°C) to desired water temperature. This way it will take less electricity to keep the heating process on and the water will remain clean as well. Note that, by any means, the tub’s water temperature shouldn’t cross 104°F, as it can cause the user health issues.  So, it is utterly important to identify and keep the tub’s temperature as per the guidelines provided above.

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I am Donald M. Beyer and I am backyard enthusiasts. I am a homeowner who has been doing DIY projects in and out of my house for many years. From simple backyard lunches to making an old-school pizza oven in my own backyard, I have a lot of experience in turning my backyard into my and my family’s personal playground.

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