When it comes to building a long lasting, high performance sauna, the material you choose is just as important as the design. That’s why Scandinavian thermowood has become the gold standard for premium sauna construction – especially for those looking to build an outdoor sauna that can stand up to real world conditions.
At Mande SPA USA, we use certified thermowood in every sauna we offer, and we’ve seen firsthand how it outperforms other wood types in both aesthetics and performance. In this post, we’ll break down why thermowood is the go-to choice for serious sauna lovers.

🔍 What Is Thermowood?

Thermowood isn’t your average lumber. It’s a natural Nordic timber, typically pine or spruce, that has been heat-treated at extremely high temperatures – between 185°C and 230°C (365°F – 445°F) – in a controlled environment using only steam and heat.
This thermal process removes moisture and resin from the wood, changing its cellular structure. The result? A highly stable, durable, and rot-resistant wood with enhanced performance – all without using any chemicals or toxic treatments.
Thermowood is essentially “baked” to perfection, transforming softwood into a material as strong and dependable as tropical hardwood – but without the environmental damage.

🌟 7 Reasons Why Thermowood Is Ideal for Saunas

Let’s take a closer look at why thermowood is such a smart choice for sauna construction, especially if you’re planning to use your sauna outdoors or in extreme climates.

1. ✅ Incredible Durability
   The thermal treatment makes the wood resistant to rot, mold, and decay. It can handle repeated exposure to heat, steam, and moisture without breaking down like untreated wood.
   That means your sauna won’t just look good the first year – it will continue to perform for 20–30 years or more with proper care.

2. ✅ Exceptional Dimensional Stability
   Ever seen wooden boards warp or twist over time? Not with thermowood.
   Because of its reduced moisture content and altered cell structure, thermowood remains stable in shape and size, even when exposed to temperature swings, heavy steam, or dry heat. It won’t shrink, swell, or crack the way ordinary lumber might.
   This makes it perfect for outdoor saunas in places like Colorado, New York, or even Arizona – where heat and humidity can vary drastically.

3. ✅ Lower Thermal Conductivity
   Thermowood stays cooler to the touch compared to many other woods. That’s a big deal inside a sauna where surfaces can reach high temperatures.
   • Less chance of burning your skin on a hot bench
   • More comfort during extended sessions
   • Safer for families and kids

4. ✅ Naturally Splinter-Free and Smooth
   Thermowood undergoes a transformation that not only improves its performance, but also enhances its surface quality.
   It’s smooth, pleasant to sit or lean on, and highly resistant to splintering. This adds to the comfort and safety of your sauna, making every session feel like a luxurious experience.

5. ✅ Chemical-Free and Non-Toxic
   Many pressure-treated woods contain chemicals, glues, or resins that can release harmful gases – especially when exposed to heat.
   Thermowood? Zero chemicals. Zero emissions. 100% safe.
   It’s ideal for health-conscious individuals or anyone looking to avoid exposure to volatile organic compounds (VOCs) or synthetic materials.

6. ✅ Environmentally Friendly
   Scandinavian thermowood is sourced from FSC-certified Nordic forests, which are among the most sustainably managed in the world. The thermal treatment process itself uses no chemicals, just heat and steam.
   Plus, because thermowood lasts so long, it reduces the need for replacement materials – lowering its long-term environmental footprint.

7. ✅ Naturally Beautiful
   Last but not least, thermowood has a rich, dark tone and a striking, modern grain pattern that looks amazing in both indoor and outdoor settings. You don’t need to stain or paint it – the natural beauty of the wood shines through.
   The longer it’s used, the better it looks. Over time, it develops a soft patina that adds to its charm and character.

🛠 Why We Only Use Thermowood at Mande SPA USA

We’ve tested countless materials over the years, and thermowood consistently delivers the best performance – hands down. It’s durable, eco-friendly, safe, and stunning to look at. That’s why we use it in every single sauna we sell.
Our thermowood saunas are handcrafted in Lithuania, Europe, designed with Scandinavian precision, and built to handle whatever the American climate throws their way. Whether you’re placing a sauna in snowy Vermont or the sun-drenched hills of California, our thermowood structures are engineered to last.

🔚 Final Thoughts: Thermowood Is the Smart Choice

There are a lot of options when it comes to building a sauna. But if you care about performance, comfort, sustainability, and style – thermowood is the clear winner.
It delivers a high-end experience with low maintenance, and ensures your investment will pay off for years to come.

🛒 Ready to Experience Thermowood for Yourself?
We’d love to help you explore your options. Take a look at our luxury thermowood saunas, or contact us if you have questions about installation, sizing, or custom features.
Your dream sauna is closer than you think – and it starts with the right wood.