The Ideal Hot Tub Temperature: All You Need to Know

Published on

June 21, 2023

Are you wondering what the ideal hot tub temperature is? You're not alone; we get this question a lot. Whether a professional spa owner or a residential one, understanding the perfect temperature for your needs is essential to enjoy your hot tub experience.

Maintaining the right hot tub temperature is essential for spa users. Submerging your body in hot or cold water can pose a significant risk of developing hypothermia or hyperthermia. This risk appears if the spa temperature isn't properly managed.

In this blog post, we'll dive into everything you need about the ideal hot tub temperature. You'll find out everything from health benefits to finding your perfect setting. Keep reading to learn more!

Expert Recommendations for Hot Tub Temperatures

Expert Recommendations for Hot Tub Temperatures
Expert Recommendations for Hot Tub Temperatures

Most hot tubs should be maintained at temperatures between 98 and 102 degrees Fahrenheit (37 and 39 degrees Celsius). This temperature range is ideal for providing a relaxing soak in hot water while remaining safe.

It is important to note that the hot water should be kept at least 20 degrees lower than the average body temperature of 98.6 degrees Fahrenheit.

Expert recommendations advise hot tub owners not to maintain water temperatures higher than 104 degrees. This can bring an increased risk of infection and other unpleasantness.  

Factors that Affect Water Temperature in a Hot Tub 

Factors that Affect Water Temperature in a Hot Tub 
Factors that Affect Water Temperature in a Hot Tub 

Keeping the right hot tub temperature is sometimes tricky and can be influenced by weather conditions, the size and shape of the spa, insulation materials, how many people use it simultaneously, and who uses it.

1. Weather conditions  

Spa owners should always be aware of how hot or cold the air outside is when using their hot tubs.

When it is hot outside, spas maintain a consistent temperature with minimal energy input. They can even heat up to desirable levels without too much effort.

Spa temperatures may drop rapidly during cooler or cold days if you don't monitor them regularly. 

You can prevent temperature drops by:

  • Covering your hot tub when not in use
  • Using a windbreak
  • Using a thermal blanket
  • Using a hot tub heater

2. Size and shape of the hot tub  

In general, smaller jacuzzis with more curves retain more heat than spas that are bigger and have sharper edges.

To maximize hot tub temperature, purchasing the smallest spa that still meets all requirements of your intended use is advised.

Hot tubs designed in an oval or kidney bean shape provide a larger surface area for retaining the hot water. This results in a warmer spa overall.

3. Insulation materials used to build the hot tub  

When comparing jacuzzis, it's important to factor in the type of insulation used to get the hot tub temperature you want.

Each spa insulation material has its own unique set of benefits and drawbacks:

  • Foam insulation has great insulating factors but can be expensive.
  • Fiberglass is economical and easy to install but does not offer top-notch hot tub temperature control.
  • Mineral wool provides superior hot tub temperature control but may require additional maintenance over time.

4. Number of people using the hot tub at once 

When many people use the spa all at once, cool body temperatures will lower the spa's overall water-warming capacity.

The maximum amount of people allowed in jacuzzis simultaneously should be strictly followed. This allows spa owners to maintain a safe and pleasant hot water temperature for all users.

You can solve this problem by:

  • Upgrading to a larger hot tub if you frequently have many people using the spa at once.
  • Increasing the water temperature to a higher-than-normal level before using the spa.
  • Insulating the spa with additional foam insulation to help retain heat.
  • Installing a hot tub heater.

5. Who Uses the Hot Tub

When choosing the right temperature for your spa water, it is essential to consider how it can affect the health of fragile categories. These categories include children, pregnant women, and elderly people.

High temperatures can cause symptoms such as nausea and dizziness in seniors, so it’s important to remember this limit for maximizing hot tub enjoyment amongst the elderly population safely.

While it may be tempting to turn up the hot water, research suggests that pregnant women should use hot tubs at a lower temperature to avoid potential risks associated with hot and/or warm water during pregnancy. Taking a break every 20 to 30 minutes is highly recommended.

This table lists the recommended spa water temperatures for children, pregnant women, and elderly people.

Recommended Spa Water Temperature
Recommended Hot Tub Water Temperature

Maintaining the Ideal Temperature of Hot Tubs 

Maintaining the Ideal Temperature of Hot Tubs 
Maintaining the Ideal Temperature of Hot Tubs 

To maintain an ideal spa temperature, hot tub users should ensure that:

  • Hot tub covers are always closed when not in use.
  • Hot tub jets are turned off after a soak.
  • They regularly clean their spas for water to circulate properly.
  • The pumps are run for at least 15 minutes each day.

How to prevent overheating in a hot tub   

Here are the basics to prevent excessive hot tub heating:

  • Monitor the temperature regularly.   
  • Ventilate your hot tub frequently.  
  • Keep the cover on when not in use.  

Safety Considerations when Using a Hot Tub 

Safety Considerations when Using a Hot Tub 
Safety Considerations when Using a Hot Tub 

It's critically important to understand body temperature impacts when you're submerged in a pre-filled spa with a high water temperature. Individuals with specific health concerns should consult their doctor before entering a jacuzzi, as body temperature can have various impacts on certain conditions.

Children who use the hot tub should be supervised by an adult at all times, and those under the age of five are discouraged from using one. For them, it's essential to ensure the perfect hot tub temperature.

Risk Factors Associated With High Temperatures 

It is important to remember that excessively high body temperatures can result from using hot tubs at high water temperatures. Research studies suggest that body heat retention in water can lead to an excessively high body temperature, with levels rising above the normal body range (98.6–99.5°F).

As a result, hot tub users can end up with:

  • Heat stroke
  • Heat cramps
  • Heat exhaustion
  • Heat rash

Health Issues  

The best hot tub temperatures for people who suffer from various health issues depend on the issue, as well as the person's history. There are some general rules regarding internal body temperature but they differ from individual to individual.

Here is a list of conditions for which you need recommendations from your physician regarding the spa water temperature:

  • Heart disease
  • Diabetes
  • Blood pressure problems
  • The use of medications that can lead to drowsiness (anti-coagulants, tranquilizers, antihistamines)

Pro tip: Avoid excessive drinking prior to using a jacuzzi, as it can lead to losing consciousness which increases the risk of drowning.


Maintaining your spa at the proper temperature is essential to both safety and enjoyment. The factors that affect water temperature can be easily managed with little knowledge and preparation.

By following the tips in this article, you can ensure that your jacuzzi is safe for all users and maintain optimal temperatures for maximum enjoyment.

Remember to always use the O-Care product in your hot tub to increase safety and extend the life of your investment. You can find us here. You can download the O-Care app for step-by-step problem-solving or ask our online water assistant to solve possible problems.


How long it takes for a hot tub to achieve the desired temperature?

It takes between three and eight hours for hot tub temperatures to reach 100-102 degrees Fahrenheit. The water's temperature typically rises by around five degrees per hour.

What is the best spa water temperature for dogs?

The best spa water temperature for dogs is between 98 and 102 degrees Fahrenheit. As each breed differs, you should start by exposing them to the lowest temperature in this range.

How hot should my spa water be when not in use?

When you are not using your hot tub, you should keep a temperature between 95 and 100 degrees Fahrenheit. This is best in terms of energy efficiency.