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Sauna Design

Sauna Climate Control


How do you design a sauna, or more importantly what do you design when you design a sauna…?

Do you design the layout?

Do you design the finished look and feel?

Do you design what will be around the sauna?


A big YES to all three, most architects design these and more to offer the client a complete package, and recently, quite a few of the homeowners have started taking an active interest in the design process to achieve not only the best looking, most usable but also supremely energy-efficient saunas.

These bits, that are usually handled by the architects, interior designers and sometimes pro-active clients themselves, are the front end of the design.

The technical aspect of sauna design what we sauna designers do is a little bit more involved...

... we make sure that the atmosphere in the sauna stays at the right temperature, the heat is evenly distributed, and most importantly, the CO2 levels are not excessive.

We don't expect you to come to us and say, 'I want this kind of a sauna with this layout', although if you do that it makes our life easier, but most of our clients come to us with an idea and the space they have to materialise that idea. And over the years we have become experts in listening to the clients and reading between the lines so we can offer you exactly what you want. We choose the most suitable materials for longevity & energy efficiency, the best equipment, and make sure that the equipment are controlled properly. We help you understand what options you have got, facilitate you to make the right choices, get you what you want and when you want it, and all within a sensible budget. We also advise you on the don’ts as much as the do’s so that the expectations are managed and met, if not exceeded.

In terms of the actual sauna build, as you will read in the following sections, you can have a variety of options at different price points, but these are all basically the ways to build the room that holds the air you will breathe in (and obviously are very important for the way the room will look), but technically they all serve the same purpose - HOLD THE AIR THAT YOU BREATHE AT THE RIGHT TEMPERATURE. 

The more important part of the design is the ventilation and circulation of air within the sauna, as that is what will affect the uniformity of humidity in the sauna, quality of experience, and also the distribution of the heat.

“The human body is designed to discharge 70% of its toxins through breathing … If your breathing is not operating at peak efficiency, you are not ridding yourself of toxins properly.”

– Gay Hendricks, PhD

Whats bad air?

If you put a plastic bag on your head and pull it tight around your neck, what will happen? After a few seconds you’ll start to feel a bit of confusion, then you’ll find it difficult to concentrate, you may feel dizzy or lightheaded, you’ll begin feeling like you are suffocating (you are), and you’ll remove the bag as soon as possible. What about something a bit larger? Perhaps being in a sealed up 6’x4’x3’ clear plastic box with a good book. Same as above except it will take a bit longer for you to come out of that box.

Those things we experienced above; the loss of our ability to think clearly, the feeling of suffocation, dizziness – are not due to lack of oxygen but too much CO2. It is too much CO2 in our blood that signals our autonomic nerve system to cause us to take a breath. We do need oxygen as well, but there is a huge amount of oxygen in the air so we nearly always get an abundance of oxygen with every breath. It’s getting rid of excess CO2 that’s the driver. (People in a sealed room will suffer from too high CO2 levels before low O2 levels will begin to cause any negative effect.)

Context in terms of sauna design

When we breathe in, a portion of CO2 in our blood gets transferred to the air in our lungs and exhaled (and dispersed, taken up by plants, converted to O2, lather-rinse-repeat – a very cool system). If all is going well the CO2 in our exhaled breath is 40,000-60,000 ppm – about 100x that fresh air we sucked in. The air we exhale then is now about 15.4% oxygen, but 5.6% CO2 (or thereabouts). We’re getting rid of a lot of CO2 with each breath, even when we are sitting in a sauna.

That CO2 is going in to the sauna… and then where?

We are still learning about CO2. For a long time it was not considered worthy of study. Ages ago it was of no concern for levels as high as 10,000 ppm. Few years ago we began getting some of the first research data on cognitive impairment. Today we know that an increase to just 550 ppm has a negative effect on us. And knowing how CO2 affects cognitive ability, companies with knowledge workers are investing considerable amounts to  provide fresher air.

Except that these effects appear temporary and so perhaps of little concern other than discomfort during our sauna. We do however know that people who sauna often in well ventilated saunas are healthier, less likely to suffer cardio problems or dementia and live longer.

What is a poorly designed sauna?

A poorly designed sauna is primarily a poorly ventilated sauna, and that is no different to a bag tied around our neck. If stale exhaled CO2 laden air is not removed and replenished by fresh outside air then CO2 levels will rise and our blood CO2 will rise along with it. Our sauna needs to breath just as we do. It is in effect an extension of our own respiratory system. That 6’x4’x3’ clear plastic box we’re sealed up in above? That’s how much space each person has in an average sauna.

Sauna Design Approach

Our first and primary sauna design goal then is the effective ventilation for removal of excess CO2, followed by air circulation within the sauna to minimise temperature difference between the upper and lower layers of air.

This is the first time I am hearing about it, is it something like air conditioning in a sauna?

Something similar, yes.

Currently, apart from the accumulation of CO2 that we can deal with proper ventilation, the other main problem in the modern saunas is simply that the top levels are too hot, while the lower levels are too cold. This, together with a lack of oxygen at head level and steam that both scalds the skin and doesn’t last long, results in an unpleasant, tiring sensation.


We use a patented solution, called the Saunum Base, that mixes steam from the higher levels and cold air from the lower levels, filters it through Himalayan salt crystals and distributes it throughout the room, creating more moisture, a more even temperature, and more oxygen at head level, which all leads to more efficient sweating and a more pleasant experience. This also provides more sauna design flexibility as it eliminates the need for high benches in order for the whole body to sit in an even heat. This makes it suitable for modern contemporary single bench saunas, such as steam sauna combinations next to each other behind glass fronts.

Saunum Base Solution is an indoor climate control system that we incorporate discreetly within our design so that its unnoticeable, and it mixes the extremely hot steam from upper levels and cold air from the lower levels. The air layers and steam are then mixed inside the device and a smooth air-steam mixture comes out of the device that ensures a more even temperature throughout the sauna room. The device also adds Himalayan salt ions into the air, which have a healthy effect on the skin and respiration system. By changing the settings, the climate control system allows you to turn a regular sauna into a hot steam home sauna. 


Once properly designed and installed, this system enables the sauna experience to be softer for the whole body, with increased active sweating,  extended sauna session with a stimulating effect.

Our new build climate controlled saunas use a combination of HUUM Sauna Heaters and Saunum Base Solution, but we can also install climate control to all kinds of saunas, new or existing, just send us a photo and ask us free advice!  

The prominent characteristic of a well designed sauna - 'Löyly'


Löyly (pronounced low-lou) is not just the steam rising from the rocks as many sauna enthusiasts believe but is a combination of several critical elements. 


“There is no shortcut to perfect löyly, it is always about stones and proper ventilation.”

– Jesse Hämäläinen, Narvi Sauna Heaters, Finland, 2012

“Löyly is the Purity, Temperature and Moisture Content of the air contained inside the sauna as well as its thermal radiation.”

– 1988 paper on sauna health benefits

That 1988 paper went on to say “The purity of the sauna air is above all a factor contributing to the enjoyment of the bathing experience. The sauna air must not contain any obnoxious extent gaseous impurities, particles, or micro-organisms. The purity of the sauna air is ensured primarily by effective ventilation.”

Steam added to stale air is just that – steam added to stale air. It is not löyly. However, if you have a foundation of good fresh air that is not stale from too much CO2, that is free of perfumes, perspiration odors and other impurities and is of the proper temperature then when you add steam produced from ladling water on the stones ... you have löyly.

When people in a sauna shout LÖYLY as the steam is produced it is not for the steam itself but because the steam added to the other elements of fresh pure air of proper temperature creates löyly.

As a design package, that comes free with any sauna you buy, what we provide for the projects is:

  • Calculation of air volumes, heat losses and capacities of heating equipment required

  • Drawings for ventilation fittings layout within sauna

  • Drawings for door, glazing, cladding & benches layout within the sauna

  • Drawings for electrical wiring & sauna operation schematics

  • Operation manual for the sauna once finished

Just Call us, Email us, or fill up the form at the end of the page.

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