Saunas have grown in worldwide popularity in recent years. More and more homes around the globe are installing both dry and infrared saunas for their personal use, often as DIY projects, which raises an important safety question – do dry and infrared saunas need venting or exhaust fans?
Dry and infrared saunas should be vented to keep heat levels steady and keep fresh air moving through the room as well as to prevent mold and mildew but it is not required for home saunas. Vent kits are typically pre-installed by the manufacturer or available as a DIY option after installation.
After extensive reading and research, I have gathered all of the information you need to make your home sauna comfortable and enjoyable with proper venting.
Does a sauna need ventilation?
Saunas have been touted for their possible health benefits, such as reducing heart disease risk, lowering blood pressure, improving immune health and brain functioning, and reducing stress. But none of these benefits can be accessed if your sauna is stuffy and you can’t stay in there long enough to reap the rewards.
Saunas do require venting not for safety reasons, but for comfort. If you are installing a dry or infrared sauna at home, it is important to know how to vent your sauna for the most enjoyable experience.
If you are installing a dry or infrared sauna, you should investigate how to best ventilate the room. Here are the basics on venting a home sauna so you can avoid some common mistakes.
Where should the vent be in a sauna?
Saunas typically have a ceiling height of seven feet from the floor, allowing people to be seated near the warmest air as heat rises. Proper venting requires both a lower vent for intake of fresh air and an upper vent for exhaust.
The lower vent should be three to six inches from the floor, and close to the sauna heater, so that the warmed air rises to where people are seated. The upper vent should be placed about three to six inches below the ceiling, in the opposite corner from the inlet. It is best if the outlet directs air back to the same area from which the inlet draws ventilation.
By placing a lower inlet and an upper exhaust vent, your sauna will circulate air better and heat more efficiently via the process of convection. This is the standard in-home sauna venting specifications.
How big should a sauna vent be?
The vent size for your sauna really depends on your heater. If you have a smaller heater, you will require a smaller vent, and larger, more powerful heaters require larger vents.
Generally, if you have a 2-8 KW heater, you will require 4-6 inch openings for venting. If you have a 8-16 KW heater, you will need 6-8 inch vents. Most home saunas will fall into these ranges.
If you are installing a sauna, know how powerful your heater is before placing vents. 1 KW heats about 50 cubic feet of sauna space. If you aren’t sure how many kilowatts you need to heat your sauna, check out this helpful chart.
Do saunas need an exhaust fan?
For the most part, saunas do not require an exhaust fan. However, you may want to add a fan to your outlet vent if the temperature is unstable or the sauna feels stuffy.
An exhaust fan may be helpful if convection flow models don’t keep your sauna comfortable enough. Sometimes the vacuum created by natural venting is not sufficient to pull the air through the sauna to allow it to maintain heat and fresh air flow. In that case, adding an exhaust fan can create a more enjoyable experience.
Forced air ventilation using an exhaust fan is less common in home saunas, but is an option if your sauna is uncomfortable without it. If you do add a fan, you may need to add a lower exhaust outlet and keep the upper outlet closed when using the sauna.
Sauna ventilation requirements
Once again, venting is not necessary for a sauna to function properly, but it will make the sauna work more efficiently and give users a comfortable and enjoyable experience. However, ventilation requirements may vary by state.
As with any construction project, it is essential to get a building permit and check on any specifications that may apply in your area. Even dry and infrared saunas, though they do not create steam, may be subject to building codes for areas with high moisture or humidity.
In California, for example, saunas must be able to move 50 cubic feet of air per minute and exhaust to the outside of the building or have at least three square feet of glazed window area, half of which can be opened for ventilation. It is imperative to check local building codes before building your sauna and choosing ventilation options.
Traditional dry sauna
A traditional dry sauna uses a physical heat source, such as a wood stove or stones warmed by a heating element, to heat the ambient air and warm your body.
Oftentimes, people pour water over the warmed stones to create steam and moist heat. In this case, since steam is being created, ventilation becomes even more essential for keeping air moving through the sauna.
In an indoor dry sauna, it is important to ensure that the air coming through the inlet is cooler than the air inside the sauna. This allows for successful convection flow of air.
In addition, it is ideal to vent the sauna back into the house rather than outdoors if compliant with local building codes. Because the barometric pressure outside the home may be different than indoors, venting to outdoors may create a vacuum by which cold outdoor air is drawn back into the sauna.
In an outdoor dry sauna, the main outlet should be placed as far as possible from the inlet and heater. If possible, it should be placed under the sauna bench. This outlet will always remain open.
There should be a second outlet vent placed near the ceiling to help dry out the sauna after use.
An infrared sauna uses heat from an infrared bulb or heating element to warm your skin directly. Infrared heat is dry and creates very little moisture aside from the sweat on your skin when you use the sauna.
Ventilation is still useful for fresh air quality and air circulation, and to keep you from overheating, but not as necessary for reducing risk of mold, mildew, or bacterial growth.
In an indoor infrared sauna, the inlet may be a small vent or even a crack under the door, just enough to allow cool air to circulate.
The standard configuration of a low inlet and high outlet is ideal for venting an indoor infrared sauna.
Outdoor infrared saunas may be vented similarly to indoor infrared saunas, with a low inlet and high outlet. However, outdoor saunas will benefit from a mushroom-cap cover on the exhaust to prevent cold air from being pulled back into the sauna.
How to install a sauna vent
If you choose to install sauna vents on your own, there are several things to consider – when to place the vents, what size vents to install, and what type to use. Most sauna manufacturers do offer vent kits specific to the particular units they sell.
It is best to complete vent placement at time of installation if possible, though they can be added relatively easily later on if necessary. It is also ideal to use vent kits provided by your manufacturer if possible, made to the specifications of your particular sauna.
Ideally, you should follow your manufacturer’s instructions and utilize the materials provided with your sauna purchase to create the best venting system for your dry or infrared sauna.
Sauna vent kits
If you purchase a sauna kit from a manufacturer, it is unlikely to include a vent kit. Venting is determined by you as the consumer.
However, many manufacturers, like Superior Saunas, do offer vent kits for purchase and installation. Amazon also has a variety of sauna vent kits that you can use to make your vents more effective than simple holes in the walls.
DIY sauna vents
It is certainly possible to create your own venting systems following the configurations I have described. There are even videos to show you how to do it yourself.
However, if you want features like sliding doors, slats, or mushroom caps on your vents, it is probably easier and more affordable to purchase a vent kit.
Sauna vent sliders
A sauna vent slider allows you to open and close the vents as desired, allowing you greater control over the air flow, temperature, and air quality during your sauna experience.
Sliders can be installed over existing vents if you decide you want one after spending some time in your sauna!