Why ThermoWood® Is the Ideal Material for Saunas – Design Insights from Saunologia

Designing a high-quality sauna goes far beyond simply generating heat. A truly great sauna is defined by how it feels, how comfortable it is to sit in, how long people want to stay, and how often they return to use it. According to sauna design expert Lassi A. Liikkanen, founder of Saunologia, the real benchmark of success is simple:

“The best measure of a high-quality experience is people’s desire to stay in the sauna and use it frequently.”

Achieving this level of comfort and usability starts with one of the most important decisions in sauna construction: choosing the right materials.

Why Material Choice Matters in Sauna Design

By definition, a sauna is a hot room built primarily with wood interiors. But in modern sauna design, wood is doing much more than just covering surfaces by defining the atmosphere, safety, durability, and overall experience. As Liikkanen explains:

“It is not only for functional reasons, but also for their capability to set the mood and feeling for the sauna.”

This is where ThermoWood®, especially Lunawood ThermoWood®, stands out as a premium solution for both residential and commercial sauna construction. Crafted in Finland using only heat and steam—without any chemicals—ThermoWood® combines natural beauty with performance characteristics specifically suited for high-heat, high-humidity environments.

Thermal Comfort and Safety: A Better Sauna Experience

A sauna is a multi-sensory environment, and one of the most critical aspects is how materials feel against the skin. Benches, walls, and backrests must remain comfortable, even at high temperatures.“The materials must be chosen so that they support a high-quality thermal comfort. Discomfort can result from either the wrong materials or the wrong type of functional construction.” One of the key advantages of ThermoWood® is its low thermal conductivity, which means surfaces stay pleasantly warm rather than excessively hot. This makes it safer and more comfortable for direct contact, whether you’re sitting, leaning, or relaxing during longer sauna sessions. Another important factor is being resin-free. Traditional wood species can release sticky resin when exposed to heat, which can cause discomfort and hygiene concerns.

“Wooden materials that contain resin may start running, where people might be in touch with wall panelling and get sap on their skin or hair. That will definitely ruin the experience.”

ThermoWood® eliminates this issue entirely, providing a clean, stable, and reliable surface for all sauna applications.

Durability in Heat and Humidity: Built to Last

Sauna environments are extremely demanding. Constant cycles of heat, steam, and moisture can cause standard wood materials to warp, crack, or deteriorate over time. “Sauna materials must be resistant towards long-term changes in humidity levels and occasional water exposure, otherwise there will be structural damage.” ThermoWood® is specifically engineered to handle these conditions. The thermal modification process reduces the wood’s moisture absorption and improves its dimensional stability, helping it maintain its shape and performance over time. This is particularly important in commercial saunas, wellness facilities, and high-use environments, where materials are exposed to frequent temperature changes and heavy use.

Liikkanen also emphasizes the importance of structural stability:

“Sound materials should remain stable so that bits and pieces of benches or wall paneling don’t fall off much sooner than expected.” With ThermoWood®, the wood’s internal structure is permanently enhanced, reducing the risk of warping, shrinking, or joint failure that are common issues in traditional sauna materials.

Low Maintenance and Hygienic Performance

In both residential and public saunas, maintenance and hygiene play a critical role in long-term performance. Materials must not only look good, but they must also withstand regular cleaning and daily use. “Materials should tolerate proper deep cleaning with mild detergents and you should be able to remove dirt off of them.” ThermoWood® offers natural resistance to moisture, dirt, and bacteria, making it a hygienic choice for sauna interiors. Its low-maintenance nature means it performs reliably with minimal upkeep, while still supporting proper cleaning routines when needed. Combined with good ventilation and proper drying practices, this helps extend the lifespan of the sauna and maintain a consistently high-quality user experience.

The Role of Design, Atmosphere, and Experience

While performance is essential, materials also play a key role in shaping the architectural and visual quality of a sauna. The natural tone, texture, and consistency of ThermoWood® create a calm, refined environment that reflects authentic Nordic sauna design. From wall paneling and ceilings to benches and decking, ThermoWood® allows for clean lines, precise detailing, and a cohesive look that enhances the overall space.

Still, as Liikkanen points out, the most memorable sauna experiences go beyond physical construction: “Exceptional sauna experiences involve multiple dimensions beyond the physical shape of the sauna. It is not only the physical structure but the specific events and special people inside.” In other words, while materials set the foundation, they ultimately support something bigger: relaxation, social connection, and moments of wellbeing.

Why ThermoWood Is the Ideal Choice for Saunas

When it comes to building a sauna that performs well and feels exceptional, ThermoWood® delivers on every level. Its combination of thermal comfort, durability, dimensional stability, and low maintenance makes it one of the best materials available for modern sauna construction. Lunawood ThermoWood® offers a sustainable, chemical-free solution that brings together Nordic craftsmanship, natural aesthetics, and proven performance.

Whether you’re designing a private home sauna or a large-scale commercial wellness space, choosing the right material is key and Lunawood ThermoWood® provides a foundation you can trust. Because at the end of the day, the best sauna isn’t only built to last but it’s built to be used, enjoyed, and returned to again and again.

The Lunawood ThermoWood® Sauna Sample Box is intended for professionals who need to evaluate materials before specifying them for a project. It allows architects, builders, and sauna specialists to review the profiles, surface quality, and finish in detail – and make informed decisions based on real samples.

Order a Sample Box for professionals HERE.