To Insulate…or Not?

Why You Shouldn’t Insulate an Outdoor Cedar Barrel Sauna

When it comes to building or buying an outdoor sauna, one of the most common questions is whether or not to insulate. At first glance, insulation may sound like a smart idea—after all, we insulate our homes to hold in heat and save energy. However, when it comes to cedar barrel saunas, adding insulation often does more harm than good. Here’s why:

1. Cedar Is Naturally Insulating

Western Red Cedar and White Cedar have natural insulating properties. The wood fibers are lightweight and full of tiny air pockets, which slow down heat transfer. This means your cedar sauna already retains warmth effectively without artificial insulation. Adding layers of insulation blocks cedars nature ability to breathe. Furthermore it doesn’t significantly improve performance but does introduce new risks.

2. Moisture Management Is Key

Saunas are high-humidity environments. One of the biggest advantages of a cedar barrel sauna is that the wood can “breathe”—absorbing and releasing moisture without damage. If you insulate the walls, you trap moisture inside the structure, creating the perfect breeding ground for mold, mildew, and rot. Over time, this shortens the lifespan of your sauna rather than extending it. A well ventilated and maintained sauna will have a period of drying out after each use.

3. Barrel Design Works Naturally

The rounded design of a barrel sauna isn’t just aesthetic—it’s functional. The curved walls promote natural air circulation and efficient heat distribution, reducing cold spots and keeping the sauna evenly warm. Because of this clever design, insulation isn’t necessary to maintain a comfortable, consistent temperature. While insulating a sauna will help with heat retention, for residential use it’s not necessary. An average sauna user will spend 60-90 minutes completing several cycles of heat therapy. On average a heated sauna to 70-90 Celsius will retain the heat, without insulation, for 120+ minutes.

4. Proper Ventilation Beats Insulation

Instead of insulation, best practice is to focus on proper ventilation. A well-built cedar sauna with intake and exhaust vents will allow fresh air to flow while maintaining heat. This prevents condensation build-up, ensures oxygen-rich air, and keeps the sauna environment healthy. The Backyard Barrel saunas are equipped with sauna vents and drainage holes to allow for proper air circulation and moisture control.

5. Outdoor Performance Without Compromise

Outdoor cedar saunas are designed to withstand tough weather conditions. Cedar is naturally resistant to decay and insects, and with the right foundation and protective roof, it will perform beautifully for 20 years or more. Fresh cedar also naturally shrinks and thus the structure is subject to change in the first 2 years. These shifts can affect the installation of artificial insulation and cause issues on its own. Adding insulation complicates the structure and compromises cedar’s natural durability.

Final Thought

Insulating an outdoor cedar barrel sauna may sound like a way to save energy, but in reality, it interferes with the natural benefits of cedar and the barrel design itself. Instead, let the wood do what it does best—breathe, insulate naturally, and create a clean, dry, and efficient sauna environment. With proper care and ventilation, your cedar barrel sauna will deliver authentic, long-lasting performance without the need for insulation.