How to ventilate your sauna to achieve the perfect sauna experience

[@thesaunaheater]

Everything you need for your sauna project (US people) from: thesaunaheater.com/

[@aussiegewoehnlich]

Thank you for this explanation. In your example at 4:59 the oven is in the middle of the wall... should be the exhaust on the opposite side also in the middle of the wall?

[@thesaunaheater]

@@aussiegewoehnlich In this sauna you probably have a door in the middle, you can put the exhaust vent slightly off the middle next to the door on either site.

[@clarkenicholson9358]

Thank you for the info. I'm getting close to finishing up sauna build and was unclear of vent placement.

[@thesaunaheater]

Thank you for watching! Hope this helped. Ventilation is a difficult subject to teach as heaters and different heater requirements affect it, and things completely unknown like air pressure differences around you sauna can affect it, but I'm sure you can get good ventilation done with these instructions. We have full, more detailed online masterclass on ventilation inside The Sauna Society if you want to learn even more - www.skool.com/thesaunaheater

[@CarolinasRenovations]

Love your educational videos! Thank you so much! In reference to an indoor sauna, my understanding is that the proper ventilation is to receive intake air and to ventilate in the same room to avoid unequal pressure? Please correct me if I'm wrong. I'm at the point in my build where I'm getting ready to lay out my ventilation....

[@thesaunaheater]

Thanks, glad you enjoy the videos! If air is taken from and vented back into the same room, it can indeed help maintain balanced air pressure. However, if you vent the hot air to the same room where you take the cold air from, you're basically circulating the same air around which is not optimal. In an optimal scenario, you want to have fresh air coming in and vent the hot humid air somewhere where it does no harm. I would consult a HVAC professional on specific advice on the situation.

[@albertohorihuela]

This video is really helpful. Thank you so much for making it. Our sauna right now has no ventilation which is something I think we should correct after watching your video. Also we experience a significant temperature difference between what is read by the heat sensor (placed above the sauna unit) and the temperature on the benches. Do you think ventilation would help with making the interior temperature more even? Is there any other way to influence even temperature in the sauna?

[@thesaunaheater]

Yes, sauna ventilation is not something you can do but a mandatory part of real sauna. Above the heater is better, but it's below in the US, since the air then cools the over heat limiter which exist only in the US with UL listed sauna heaters. The UL listing makes sauna heaters worse, and this kind of limitor with ridiculously low limit does not exist in Europe, since we don't have UL listings. Your sauna is unequally temperature, because hot air is lighter than cold, thus rising to the top of the sauna. There's nothing bringing it down since you have no ventilation. Ventilation will fix your sauna essentially, there's 0 saunas that are not ventilated in Finland.

[@allaspectsfencing]

Hi there can you just use natural air vents. Or do they need to be mechanically vented

[@thesaunaheater]

Depends on your situation. With electric sauna heaters, mechanical tends to work better but you can do natural ventilation as well, it just might not work so well with electric heaters. Very dependent on your unique situation.

[@angeliqueortega1544]

Is it okay if I put clear sealer on my wood benches? Any cons?

[@thesaunaheater]

Depends what kind of sealer. If it's suitable for hot and humid environment and can handle high temperature changes you can.

[@capedcrusaderforbuilders9671]

Our sauna in an unconditioned large garage-barn has its heater wall common to the large garage space. Venting above the sauna or below would mean having the intake from the unconditioned garage. Warm in summer, cold in winter. Is it OK to vent (intake) from such a room? The garage space is huge, 24 feet by 30 feet, 12 foot walls and the roof overhead vaulting up to 24 feet, so thousands of cubic feet of unconditioned air. The exhaust vent will go to outside on the wall opposite the heater.

[@thesaunaheater]

The quality of your sauna air will be determined by the quality of the air in this garage space. So in terms of air circulating yes but I would just see what the air quality in that garage space is in general and then decide based on if that's the fresh air you want to circulate in your sauna.

[@garrethay8013]

The first room you depicted showed where to place the intake vent. Where would you place the exhaust vent if the only access to the outside air was the same wall as the intake vent?

[@thesaunaheater]

This depends about the placement of the sauna heater, about the size of the sauna etc. If it's a smaller (2-3 person sauna) I might place intake and exhaust on this same wall on the opposite corners of this wall, maybe...

[@garrethay8013]

Good to know. Thank you for the reply and the information!

[@AtlanticwayExplorer]

I’m confused, you say set the air intake below the electric heater and above it, which is better? Also if the vent opposite is closed down to about 20% will the heat sink and exhaust through the lower vent under the bench? If that vent is open halfway for example. I’m talking about an outdoor sauna with an electric heater

[@thesaunaheater]

In the US, below sauna heater vent is needed to cool down an overly sensitive UL sensor (in case your heater has one). Outside of North America, these sensors are not so sensitive so it doesn't matter. The above sauna heater vent is for the air to mix with rising hot air and provide oxygen for sauna goers. Ventilation is a complicated topic and there are so many variables (heater brand, model, air pressures around the cabin, etc), that it's impossible to explain in one video. We have a free online course on ventilation at The Sauna Society, which offers more information for you I would recommend watching it - www.skool.com/thesaunaheater/about

[@AbdulAzeem-o3v]

Can we dump supply air from the AHU which will be at 24 degree Celsius to the sauna as fresh air ?

[@thesaunaheater]

Yes, you can do that

[@another5246]

What would happen if the vent is on the side wall and inline with the stove and therefore not above the seats as in your picture?

[@thesaunaheater]

Typically in electric saunas, there are 2 exhaust vents (so 3 in total). The one above the benches should be an adjustable 'drying' vent, meant for the steamy air to go out of the sauna, a vent you open if needed and you want to get rid of some humidity. The one under the benches is for air circulation, so the hot air gets drawn to your feet level as well. With wood fired saunas, you won't have the one under benches since the fire chamber is acting as mechanical exhaust on the floor level, ensuring air circulation.

[@willmcgregor7184]

Thanks I am planning an outdoor sauna (likely 5 ‘ x 5’ )with a wood heater. Seems few sources emphasize ventilation . What size duct (3”, 4” etc) do you recommend? Thanks

[@owenwheatley9743]

4” seems to be a more common standard size for sauna vents, and if you make it adjustable then you can just restrict it down anyway.

[@thesaunaheater]

Since they're adjustable, and ventilation is not an exact science, go rather bigger than smaller. The size of these vents can vary based on the size of the sauna, but a common rule is that the vent area (both intake and exhaust) should be at least 1 square inch per 1 cubic foot of sauna space. For example, a sauna that is 6 feet long, 7 feet wide, and 7 feet high has a volume of 294 cubic feet, so the total vent area should be at least 294 square inches. When you have adjustable, you can experiment and find a good balance.

[@willmcgregor7184]

Thank you!

[@sov19871987]

You can also can have a gap underneath the door

[@thesaunaheater]

True! I will film an updated version of this video soon, I have some new information about ventilation that I got after discussing the contents of this video with my fellow sauna experts.

[@victoriabryan3609]

@@thesaunaheater Any idea when you’ll get a chance to post the update? I’m in the middle of building a sauna and could really use some help figuring out the ventilation.

[@thesaunaheater]

@@victoriabryan3609 You can join The Sauna Society which is our free community where we help everyone with their specific questions about their individual sauna build, it's absolutely free - www.skool.com/thesaunaheater/about Even tho this video does not talk about every possible scenario when it comes to sauna ventilation, this is still great general guide for it, so it's not on top of our priority list atm to make the updated version, but sooner or later it is coming!

[@Dharmagoose]

Can you explain exactly how you use these vents during a sauna? And the one placed behind the stove… Is this one something that gets opened and closed or is it fully open? my woodstove sits away from the wall a bit so I could access behind the stove from the side.

[@thesaunaheater]

@@Dharmagoose The one providing air for both burning and oxygen for sauna goers is always open. One on the roof 'drying vent' is opened only after sauna going. These are all you need in a wood fired sauna. We have a course on this inside our community, it's free to join - www.skool.com/thesaunaheater/about

[@urloony]

Great video. I built and have been using my sauna for the last two years and am trying to improve ventilation, maybe you can help? I have an 8x8x8 sauna room with a wood burning Kuuma stove and an adjacent 8x8 cooling room. I have one 4-1/2" vent in the sauna near the ceiling on the opposite wall from the stove. The stove draws air from the cooling room under the sauna door that has a 2" gap and from a 2" drain on the floor near the stove. I'm debating whether I should add an additional intake behind the stove or an additional vent under the top bench, or both. What do you think?

[@thesaunaheater]

Since you're using a wood-fired heater, it's essential to position the air intake correctly. I recommend placing the intake behind the stove, not behind the benches. The issue you're facing is that the stove isn't getting fresh air into the sauna. Currently, the stove pulls fresh air from under the door directly into the fire chamber, meaning the sauna area itself doesn't receive enough fresh air. For better airflow, you want fresh air to enter, mix with the rising hot air and löyly (the steam from throwing water on the stove), providing more oxygen to the sauna. This will improve the quality of the air and ensure it circulates efficiently-first rising and then eventually being drawn down to the stove's fire chamber.

[@urloony]

@@thesaunaheater Thank you for the quick response. My wood stove is in the corner of the room and I have two 3'x5' cement boards hanging on the wall behind the sauna stove. One at the back of the stove and one along the side of the stove. These are required per my state building codes. The wall behind the cement board is wood and there is 1" air gap between the wall and the cement board. Do you recommend I put the intake vent through the wall behind the cement board close to the stove or find an open wall area further away from the stove unobstructed by the cement board?

[@Noonelson]

is it ok to exhaust into the house duct work, i have an HRV that takes stale air from the cold air return and vents it outside.

[@thesaunaheater]

Yes based on this info you can add the sauna ventilation into your houses mechanical ventilation system.

[@nthibode]

Are two exhaust vents recommended no matter the size of the sauna? Ours will be quite small, about 120-140 cubic feet. Thanks!

[@thesaunaheater]

Very small saunas can do with one only, put it under the sauna benches.

[@angeliqueortega1544]

Is it okay if my sauna is made out of stone and not wood?

[@thesaunaheater]

Yes that is okay, you just need MUCH larger sauna heater to heat up that thing and you need to cover the benches with wooden blanks because stone gets way too hot to sit in when heated.

[@AvironAndy]

Love your videos. When should I keep the vents open/closed? Is a good rule of thumb, closed when heating so it heats up faster, and open when in use? And keep it open after so the moisture goes away?

[@thesaunaheater]

Yes, exactly like you said. That's a good rule of thumb. Keep them closed when heating up and open when you go into the sauna. Then after sauna going, leave them open so the sauna will dry.

[@southern0949]

Open the door after the sauna session too. The residual heat will quickly dry the sauna out. I have just finished a 1.8m x 1.2m and 1.9m high outdoor sauna with a 4.5kw Harvia electric heater with rocks. It has a glass door, and I noticed when I had it full of people (and I was outside!) and they were saying it wasn't heating up fast enough, that there was some leakage around the glass door. When I pre-heat the sauna now, I close all vents (intake 50mm diameter under the heater and exhaust 100mm diameter opposite the heater, both at floor level) and keep the door completely shut (currently with a stick! I will have to get something better, lol). It takes 45-50min to heat up to 85oC, and then when I go in, I open the vents and make sure the door seals well, currently using a small rubber band(!), but a magnetic latch is in order. I'm still experimenting, and as the sauna is small, the vent under the heater might be too much, as there is a gap under the door. Also, the exhaust vent might get too much opposition from the prevailing wind, so still need to experiment. In any case, it is a fantastic experience, and my guests just love it, so I have done something right! Enjoy the loyly!

[@tjwatkins8381]

I have three vent holes behind the sauna heater and 2 holes on the opposite side of side but my sauna stays very cool at the bottom and hot on the top bench. What can I do?

[@thesaunaheater]

Sometimes it's possible that the air pressure around the sauna cabin differs (meaning the air pressure is very different on the location of the intake vent than the exhaust for example), and the ventilation does not work because of that, the air won't circulate. There's no easy fix for this, would need to consult your local HVAC professional about it. It's also true that eliminating the temperature differences completely between lower and higher levels of the sauna is impossible without HVAC machines that force the air to circulate. There's many things that effect this, your sauna heater choice, and other sauna construction practices included.

[@tjwatkins8381]

The sauna is in my garage so no HVAC and the air circulation could be problematic - do you think if I open the side door to the garage the air ventilation would improve?

[@tjwatkins8381]

Or should I just put my air purifier / fan close to the intake?

[@thesaunaheater]

@@tjwatkins8381 Try playing around with the fan and see if you can make it work, but as said in some sauna models you just can't eliminate the temperature differences completely. But yes, if you can get the air to circulate in the sauna that would fix the problem at least partly.

[@douglasshive9872]

I want to install me mechanical ventilation & exhaust . Fantech was recommended to handle the high heat. Do you know any other options?