Thermowood vs Regular Wood Sauna: Which One to Choose?

Cubo L Plus Termo Sauna

Are you considering adding a sauna to your outdoor space, but unsure whether to opt for a regular wood or a Thermowood sauna?

Thermowood has been gaining popularity in recent years, so we’ve compiled a list of thermowood sauna benefits to help you make an informed decision.

But before we go into the benefits, let’s understand what Thermowood actually is.

What is Thermowood?

Thermowood, also known as Thermally Modified Timber (TMT), is a type of timber that has been treated at high temperatures, typically between 160-230°C, in a low-oxygen environment.

This process, known as thermal modification, results in permanent changes to the wood’s properties across its entire cross-section, including degradation of hemicelluloses and α-cellulose, partial restructuring of lignin, and expulsion of volatile accessories like resins.

The result is a product that is more durable, resistant to decay, and less affected by humidity and external weather conditions.

The industrial-scale ThermoWood process was developed in Finland in the 1990s. The Kärkkäinen brothers, Aulis and Olavi, are commonly known as the inventors of this process.

The term “ThermoWood” is a registered trademark owned by the International ThermoWood Association, and the normative basis for TMT is the European technical specification CEN/TS 15679:2007.

The production process of thermowood involves several stages. Initially, the wood is dried and prepared for heat treatment. This is followed by the thermal modification process, which is carried out in a special chamber kiln.

The wood is heated to high temperatures under reduced oxygen concentration, which changes its chemical composition.

After the heat treatment, the wood is rapidly cooled. The entire process is computer-controlled to ensure consistent results.

Thermowood is environmentally friendly as it does not involve the use of any chemicals. It is completely recyclable and at the end of its life, it can be burned and converted into bioenergy or recycled.

It is also more resistant to fungal damage and less susceptible to mold and rot, making it a sustainable choice for various construction and design applications.

Durability & Minimal Upkeep

CUBO XS termo sauna
CUBO XS Thermowood sauna

While regular wood saunas are also quite durable and can last for many years, thermowood saunas can last even longer thanks to the wood’s unique properties.

The sauna is a highly humid environment, with temperatures reaching up to 212°F. This can cause traditional wood to warp or crack over time, leading to repairs or replacements.

Thermowood, on the other hand, is less susceptible to changes in temperature and humidity, making it a more resilient option for saunas. This means minimal upkeep and maintenance over time, saving both time and money.

Moreover, thermowood has been shown to have increased resistance to termites and other pests compared to regular wood, due to its reduced moisture content and altered cellular structure.

But keep in mind, that thermowood saunas still need to be treated with a protective finish every few years to maintain its appearance, because thermowood is not UV-resistant. Without stain, it will turn from its original color to silvery grey over time.

Improved Insulation and Energy Efficiency

Cubo L Sauna Kit

Compared to untreated wood, Thermowood offers approximately 25% higher thermal insulation

This improved insulation is reflected in lower energy consumption, as less thermal energy is needed to heat spaces in cold weather, and less air conditioning is required in hot conditions.

This makes Thermowood saunas a more cost-efficient choice in the long run.

Thermowood is also more resistant to heat than conventional wood. In a sauna setting, this means that Thermowood heats up much less, even when the heat is set to the maximum limit.

This not only makes the sauna more comfortable for users but also eliminates the risk of burning.

Thermowood is Sustainable

Thermowood is usually sourced from well-managed, sustainable forests. Companies like Lunawood and Thermowood ensure the wood comes from forests where responsible forestry practices are followed.

This includes cutting less than the annual growth and replanting more trees than harvested. These forests are often PEFC-certified, which guarantees they’re managed in an environmentally, socially, and economically sustainable way.

Making a choice

While thermowood has many benefits, there’s one drawback: its cost. The process of thermally modifying wood adds to its overall price, making it more expensive than regular wood options.

How expensive? It’s difficult to know exactly, as prices vary depending on several factors, but generally speaking, thermowood can cost up to 2 times more than untreated wood.

Is it worth the extra cost? That depends on your priorities. If sustainability, durability, and energy efficiency are important to you, then thermowood is a clear choice.

However, regular wood is perfectly fine for most sauna users, and the cost difference may not be worth it. In fact, most outdoor saunas are still built with regular wood.

Ultimately, there’s no right or wrong choice here. Consider your priorities and choose the option that best fits your needs.

Your next steps

BZB Cabins and Outdoors offers a variety of Thermowood saunas as DIY kits, which you can put together yourself or let us do it for you. We also have regular wood outdoor saunas available in different sizes and designs.

Looking for a more personalized option? Our team can work with you to create a custom outdoor sauna that fits your needs and space perfectly.

Whichever option you choose, we at BZB Cabins and Outdoors are committed to providing you with high-quality, sustainable sauna and cabin kits that will bring you relaxation and enjoyment for years to come.


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