When selecting the best wood for your sauna, two prominent choices stand out: Cedar wood and thermally modified wood. While cedar has been a traditional favorite, especially in the U.S., thermally modified wood, also known as Thermowood, is gaining popularity globally due to its enhanced durability, sustainability, and superior performance in humid environments. This comprehensive guide explores the differences between these two sauna wood types, highlights the advantages of thermally modified wood, and explains why it might be the best choice for your sauna.
Cedar has been widely used for saunas in North America, primarily because of its availability and natural resistance to decay and pests. Its pleasant aroma and visually appealing reddish hue make it a popular choice for cedar saunas. However, cedar's dominance is largely rooted in historical availability rather than inherent superiority over other wood types.
Pros of Cedar Wood:
Cons of Cedar Wood:
While cedar has been a mainstay, thermally modified wood offers a superior alternative. Let’s explore why.
Thermally modified wood, or Thermowood, undergoes a heat treatment process that alters its physical and chemical properties, enhancing its stability, durability, and resistance to moisture and decay. This treatment involves heating the wood to high temperatures (typically between 356°F to 482°F) in an oxygen-free environment to prevent combustion.
The Thermal Modification Process:
This process results in wood that is more stable, durable, and resilient than untreated wood, including cedar.
The use of thermally modified wood dates back to ancient Nordic civilizations, where it was employed in shipbuilding. The Vikings, known for their maritime prowess, used thermally modified wood in their ships, which allowed them to withstand harsh sea conditions and last for centuries. This historical use underscores the incredible longevity and resilience of thermally modified wood.
While cedar has been traditionally favored, thermally modified wood offers numerous benefits that make it a superior choice for modern saunas.
1. Unmatched Durability and Stability
Thermally modified wood has a reduced ability to absorb moisture, making it highly resistant to warping, swelling, or shrinking. This stability is crucial in a sauna environment, where high humidity is constant. Unlike cedar, thermally modified wood maintains its shape over time, requiring fewer repairs or replacements.
2. Enhanced Rot and Decay Resistance
Thermowood’s resistance to rot and decay is superior to cedar, thanks to the removal of organic compounds that typically attract fungi and insects during the heat treatment process. This makes thermally modified wood ideal for both indoor and outdoor sauna applications.
3. Eco-Friendly and Sustainable
The thermal modification process is chemical-free, relying solely on heat and steam, making it an environmentally friendly option. Thermally modified wood is also sourced from sustainably managed forests, providing a greener choice compared to cedar.
4. Superior Thermal Insulation
Thermowood has excellent thermal insulation properties, ensuring efficient heat retention and comfort within the sauna. Its low density allows it to heat up quickly without retaining excessive heat, enhancing the sauna experience.
5. Aesthetic Versatility
Thermally modified wood is available in various species, including ash, pine, and spruce, offering diverse colors and grains to match any design preference. Its rich, deep tones and smooth finish can enhance any sauna style, from traditional to contemporary.
6. Non-Toxic and Safe
Unlike some treated woods, thermally modified wood does not off-gas or emit harmful chemicals, making it a safe choice for high-heat environments like saunas.
7. Cost-Effectiveness
Although thermally modified wood may have a higher initial cost compared to cedar, its longevity and low maintenance needs make it a more cost-effective option in the long run.
At Havenly, we utilize a variety of thermally modified woods in our custom sauna designs to create stunning and durable saunas. Here’s a look at the different types of Thermowood we offer:
Thermo Aspen
Known for its light color and smooth texture, Thermo Aspen offers a clean and contemporary look. It is highly stable and resistant to heat, making it a popular choice for sauna benches and interiors. 
Thermo Radiata Pine
This wood boasts a rich, warm color that adds a luxurious feel to any sauna. Thermo Radiata Pine is strong and durable, with a pleasant grain pattern that enhances the visual appeal of the sauna.
Thermo Spruce
With its knotty appearance and rustic charm, Thermo Spruce is perfect for those seeking a traditional sauna look. It provides excellent insulation and is highly resistant to moisture. 
Thermo Alder
Thermo Alder features a unique reddish hue and fine grain, making it both durable and aesthetically pleasing. Its thermal properties make it a superior choice for sauna construction.
Affordability and Value:
One of the major advantages of thermally modified wood is its cost efficiency. The price per linear foot for Thermowood is approximately half that of clear cedar, yet it delivers a superior product in terms of durability, stability, and performance. This makes it an excellent choice for custom saunas, allowing you to achieve the sauna of your dreams without breaking the bank.
When comparing sauna kits made from thermally modified wood and cedar saunas, it’s evident that thermally modified wood provides enhanced performance, longevity, and sustainability. Here’s a quick comparison:
| Feature | Thermally Modified Wood | Cedar |
|---|---|---|
| Durability | Highly durable with excellent resistance to rot, decay, and moisture. | Naturally durable but susceptible to some warping and fading over time. |
| Stability | Extremely stable with minimal shrinkage or swelling. | Stable but can warp or swell in high humidity if not properly maintained. |
| Thermal Insulation | Excellent thermal properties, providing efficient heat retention and comfort. | Good thermal properties but slightly less efficient than thermally modified wood. |
| Maintenance | Low maintenance due to high resistance to moisture and decay. | Requires regular maintenance to retain color and resist wear. |
| Aesthetic Appeal | Wide variety of wood types with rich tones and sleek finishes. | Traditional look with warm, reddish hues; can fade without upkeep. |
| Eco-Friendliness | Chemical-free process using sustainably sourced wood; highly eco-friendly. | Cedar is naturally grown but may involve deforestation concerns. |
| Cost | Lower or equal initial investment and more cost-effective in the long run due to longevity and low upkeep. | Generally similar upfront cost but may require more maintenance over time. |
While cedar has its merits, thermally modified wood offers superior durability, stability, and eco-friendliness, making it the ideal choice for modern saunas. Its impressive thermal insulation, low maintenance, and wide range of aesthetic options make it a top pick for both custom and kit saunas. For those seeking a sauna that combines beauty, performance, and sustainability, thermally modified wood is the clear winner.
Explore our selection of thermally modified woods and sauna kits made from Thermowood, or get started with a free custom sauna design and materials quote to create your dream sauna.
1. What is thermally modified wood, and how does it compare to cedar?
Thermally modified wood undergoes a heat treatment process that enhances its durability, stability, and resistance to moisture and decay, making it superior to cedar in terms of performance and longevity.
2. Why is thermally modified wood better for saunas than cedar?
Thermally modified wood offers superior resistance to moisture and decay, enhanced stability, better thermal insulation, and a longer lifespan with less maintenance compared to cedar.
3. What are the different types of thermally modified woods available for saunas?
At Havenly Decor, we offer a range of thermally modified woods including Thermo Aspen, Thermo Radiata Pine, Thermo Spruce, and Thermo Alder, each with unique characteristics and aesthetic appeal.
4. Is thermally modified wood eco-friendly?
Yes, thermally modified wood is eco-friendly because the modification process is chemical-free, relying solely on heat and steam. It is also sourced from sustainably managed forests.
5. How does the cost of thermally modified wood compare to cedar?
Thermally modified wood typically costs less per linear foot than clear cedar while offering a superior product in terms of durability and performance, making it a cost-effective choice for saunas.
6. Can I use thermally modified wood for both indoor and outdoor saunas?
Yes, thermally modified wood is highly resistant to the elements and is suitable for both indoor and outdoor sauna installations.
7. Why was cedar traditionally used for saunas in the U.S.?
Cedar was commonly used in the U.S. primarily due to its availability and natural resistance to decay and pests. However, thermally modified wood offers greater benefits and is becoming the preferred choice worldwide.
Explore our selection of thermally modified sauna woods and discover the advantages of this innovative material for your next sauna project.
*Havenly and its associates do not provide medical guidance. Consult a licensed doctor for medical advice. All of the information contained in this website is for information purposes only. Results of using our products vary on an individual basis and no immediate permanent or guaranteed solutions can be provided. We reserve the right to change, without notice, anything contained within the article. Havenly shall not be held responsible for printing variations.
Leave a comment