Are Saunas Dry or Humid? (Plus How to Add Humidity in the Sauna)

It is very easy to confuse a sauna with its neighbors—the sanarium and the steam room. Nevertheless, although all three of these rooms are meant to be used to relax through heat provision, they do so in different ways.

Saunas are not humid, using dry heat instead of the wet heat associated with humidity. They have a humidity level ranging from 5% to 10%, which can be increased to up to 30% by throwing water on the stones to produce steam. 

If you want to learn more about saunas and understand the difference between a traditional ‘dry’ sauna and a wet sauna, also known as a steam room, keep reading. This article will give you an in-depth look at the merits and demerits of both.

What Is a Sauna?

A sauna is a small room containing wooden benches that individuals can lounge on as they enjoy the dry heat provided by the sauna.

Heating rocks generate this dry heat to very high temperatures. The rocks can be heated by the burning of wood, the use of an electric heater, or in more advanced cases, infrared rays. A sauna’s temperature is usually at approximately 80℃ (176℉).

How Is Heat Transferred in a Sauna?

Heat is transmitted throughout the room by the movement of hot, dry, air—which, when it comes into contact with you, is transferred through a process called convection. It is also conducted through the wooden benches, which, despite being insulators, can conduct some amount of heat through them to the users of the sauna.

How to Add Humidity in the Sauna

Although most of the heat in a sauna is dry heat, it is possible to make it more humid by adding a very small quantity of water to the rocks when they are very hot. You can do so with a ladle, an automated system, or just throw it on with your hands. Be sure only to do this at hotter temperatures because doing so at a cooler temperature could make them crack, thus necessitating a replacement.

The method of heat transfer in a traditional sauna is unlike the method used in a steam room. A steam room does not use dry heat; instead, it fills the room with vast steam quantities at a temperature that is maintained at approximately 110℉ (43.4℃).

This means that a steam room is much more humid as compared to a sauna, with humidity levels reaching around 100%.

Is High Humidity Better?

Humidity, like all things, should come in moderation. When humidity levels get too high, it can be extremely dangerous for the human body. There is a reason why everybody counsels you only to use a steam room for less than fifteen minutes.

The reason for it is because high humidity can make it seem like it is hotter than it actually is. If that statement sounds confusing, think of the difference between a sauna and a steam room. A sauna is much hotter than a steam room, but you can stay much longer in a sauna than a steam room.

This is because high humidity prevents the evaporation of sweat from your body. This is a big deal because your body loses heat by the latent heat of vaporization that is lost when your sweat evaporates.

When your sweat doesn’t evaporate, all of the heat is stuck within your body, causing you to produce increasing amounts of sweat. If this cycle is continued for too long, it is possible to suffer various adverse consequences such as heat stroke. 

Other problems associated with high levels of humidity are:

  • Dehydration
  • Fatigue
  • Fainting
  • Heat exhaustion
  • Muscle cramps

However, if you spend only the appropriate amount of time in conditions of high humidity like a steam room, you can actually face a number of benefits. For example, this study conducted by M. Singh and associates shows that steam therapy can actually help with certain acute lower respiratory diseases, like bronchiolitis. 

Aside from the respiratory benefits, an increased level of humidity does not engender any additional special benefits. Using both dry heat or wet heat will both:

  • Improve blood pressure
  • Decrease muscle soreness and pain
  • Reduce stress
  • Improve circulation

Should My Sauna Be Dry or Humid?

The amount of humidity that you want to have in your sauna is entirely dependent on you. Humidity affects different people in different ways, so you should consider any past reactions with dry versus humid air and any health afflictions that you might have.

For instance, if you have conditions that can be aggravated by humidity, like rheumatoid arthritis or asthma, you should avoid throwing water on the rocks at all. On the other hand, if you’re suffering from a cough or a sore throat, it could be beneficial for you to throw quite a bit of water on the rocks and generate steam because the steam and humidity could help you recover faster.

In the end, it all just depends on your mood. Because saunas will only ever achieve a maximum of 30% in humidity levels no matter how much water you throw on the rocks, it is much safer to use a traditional dry sauna and bask in the steam rather than using a steam room. However, be sure to leave the sauna as soon as you stop feeling unwell at all, no matter the humidity level. 

If you’re really fond of high humidity and accidentally have a sauna instead of a steam room installed in your home, you can try to rectify this matter by turning your sauna into a makeshift steam room. Try calling the experts in your area to see if it is possible to install a steam room generator in your sauna.

You would think it would be easy, but there are many requirements to properly install a steam generator—you need to see if there’s a power supply nearby, know how to hook water pipes to the generator, etc.

If you only plan on using a ‘wet heat’ steam room occasionally, you’ll probably find one at your local gym that you can use if you get a cheap membership. You should only get a steam generator if you’re very passionate about it because they are rather expensive, like this CGOLDENWALL Steam Generator.

Who Can Use a Sauna?

Although humidity can feature in both steam rooms and saunas, the overlapping criterion is the heat. Both saunas and steam rooms are extremely hot, and while this is a benefit to most people, it’s not to others. Here is a list of people who should not be using a sauna:

  • Pregnant women
  • Children below six
  • Sufferers of fever
  • Anybody who has recently ingested alcohol
  • Those with angina-related chest pain
  • Those with severe orthostatic hypotension


In conclusion, a sauna uses dry, arid, hot air and is usually much safer to use than a ‘wet’ sauna, which is extremely humid. However, it is possible to change humidity levels in the sauna by adding steam on the rocks. No matter if you decide to use a sauna or a steam room, keep in mind that both locations generate a great amount of heat, which could potentially be detrimental to your health.

Always ensure that you get cleared by a doctor to use either a sauna or a steam room, and see that you take proper care of your body when using a sauna, like your hair, which could get very frizzy if you leave it without wrapping it in a towel or using conditioning products.