Sauna Materials Heat Resistance: Tempered Glass, Acrylic, PC

A high-quality sauna is not only known for its design but, more importantly, for its safety and user experience. One of the most overlooked aspects when building or purchasing a sauna is the choice of sauna materials. Since temperatures in traditional saunas can reach up to 110°C, using the wrong sauna materials can compromise safety, shorten the sauna’s lifespan, and lead to costly repairs.

Among the many sauna materials, wood and glass are essential components. In this article, Alphasauna shares insights into the heat resistance, applications, and suitability of the three most common sauna materials: tempered glass, acrylic glass, and polycarbonate (PC).

Why Heat Resistance Matters in Sauna Materials

Besides wood, the use of tempered glass, PC boards, and acrylic glass can also create different sauna experiences. Traditional saunas operate in high-temperature, high-humidity environments, where materials are exposed to thermal expansion, moisture absorption, and sudden temperature fluctuations. If tempered glass lacks sufficient heat resistance, it not only carries a risk of breakage but also reduces overall heating efficiency, making it harder to maintain the desired temperature. Low-quality PC boards and acrylic glass may release harmful substances when heated, posing potential health risks. Therefore, choosing materials with excellent heat resistance is essential to ensuring both safety and a comfortable sauna experience.

Why Does a Sauna Need Insulation?

Heat Resistance of Common Sauna Materials
To enhance light transmission in saunas, three common materials—tempered glass, acrylic glass, and PC—are often used. Each material differs in heat resistance and visual quality. Below, I will explain the heat resistance characteristics of these three materials at Alphasauna.

Tempered Glass

Tempered glass is a leading choice among sauna materials. Strengthened through physical or chemical processes, it is 4–5 times stronger than standard glass and breaks into blunt-edged pieces if shattered, minimizing injury risks.

Alphasauna uses 8mm tempered glass in clear, brown, and black. It withstands 200–300°C long-term, Ccold as low as -60°C, and sudden temperature changes up to 200°C. This makes it one of the most reliable sauna materials for both indoor and outdoor saunas.

Acrylic Glass

Acrylic glass is not actually glass; it is a transparent plastic material. It is lightweight and has impact resistance 10–20 times greater than ordinary glass, making it highly shatter-resistant. However, it is less durable than tempered glass and more prone to scratching. In traditional saunas, it is important to keep the sauna heater away from acrylic glass, as excessive heat can cause deformation.

Acrylic glass is also commonly used in saunas supplied by Alphasauna. Available in clear and brown variants, it can withstand long-term temperatures of 120–130°C, short-term (instantaneous) temperatures of 140–150°C, and minimum temperatures of -15 to -30°C. It is often used for panoramic back walls in traditional saunas, providing both light transmission and a degree of privacy.

Polycarbonate (PC)

Polycarbonate is one of the most affordable sauna materials, offering good light transmittance and durability. It withstands 30–100°C, with cold resistance down to -100°C. It performs well as a sauna skylight material, adding natural light and atmosphere.

The Application of Different Sauna Materials in Sauna Roomss

Based on the heat resistance of tempered glass, acrylic glass, and PC panels, it is clear that each material has distinct applications in traditional saunas. Below are some examples of their uses, as provided by Alphasauna.

Tempered Glass

Tempered glass is primarily used for sauna doors, regardless of the sauna type. Its high heat resistance allows it to remain stable in the fluctuating temperatures of a sauna. Its strength also enables it to withstand frequent door use, making it suitable for both personal and commercial saunas.

Since sauna rooms are generally small, windows and panoramic glass back walls are often installed to enhance light transmission. This not only brightens the space and creates a sense of openness, but also complements the wood, adding visual depth. Moreover, in both traditional and infrared saunas, tempered glass windows and back walls allow users to view the outdoor environment while increasing their sense of security and comfort.

Acrylic Glass

Compared to tempered glass, acrylic glass is often used in semicircular designs on the back walls of traditional outdoor saunas. Clear acrylic glass provides excellent light transmittance, allowing more sunlight into the sauna and making the room feel more spacious and modern. Brown acrylic glass is ideal for users who want privacy while still enjoying a view of the outdoors.

PC Sheet

PC sheets are the most affordable of the three materials and are easy to cut and install. They are commonly used as skylights in saunas, providing natural light while maintaining privacy and accommodating a wide range of design preferences.

How Should I Choose These Sauna Materials?

Although we have a basic understanding of these three materials, many consumers still ask, “How should I choose the right materials for my sauna?” Alphasauna provides the following guidance from both outdoor and indoor sauna perspectives to help you make an informed choice.

Traditional Outdoor Saunas

For outdoor saunas, tempered glass is undoubtedly the best choice. Used for panoramic glass walls and transparent doors, it is highly durable, able to withstand temperature fluctuations, wind, and rain, and relatively easy to maintain. For commercial saunas, a unified design not only enhances the overall aesthetic but also helps strengthen the brand’s reputation.

PC sheets are commonly used for skylights or domes due to their lightweight nature and impact resistance. However, prolonged exposure to sunlight and high-temperature steam can cause yellowing. When using PC panels outdoors, it is recommended to add a sunshade and clean them regularly with a neutral detergent and a soft cloth.

Acrylic glass is ideal for larger yards or holiday homes. Its creative design allows ample natural light to enter, creating a spacious feel while still maintaining a degree of privacy.

Indoor Saunas

Indoor saunas differ from outdoor ones in maintenance and durability. Their smooth surfaces resist mold and discoloration, typically requiring only a damp cloth for cleaning. Since indoor saunas are generally smaller, tempered glass offers excellent light transmittance, brightening the space and enhancing a modern, airy feel.

Acrylic glass, with its larger footprint and cylindrical design, is more suitable for outdoor use. (Customization is available, and Alphasauna can meet specific indoor requirements upon request.)

PC sheets, although shielded from sunlight indoors, can still yellow and lose transparency under prolonged exposure to high-temperature steam. This is especially important in commercial saunas, where clients prefer bright, transparent, and luxurious interiors. Compared to tempered glass, PC sheets are less practical and require careful maintenance; once scratched or yellowed, they are difficult to restore.

Conclusion

No matter which sauna material you choose—tempered glass, acrylic glass, or PC panels—quality is crucial for overall safety and comfort. Alphasauna rigorously selects all three materials, ensuring they are fully suitable for the high-temperature, high-humidity environments of traditional saunas. Simply choose the material that best meets your needs.

If you are considering purchasing a new sauna, you can also contact us. As a leading sauna manufacturer in China, Alphasauna offers a wide range of prefabricated and high-end custom sauna solutions, providing personalized, one-on-one service to help you quickly understand and select the perfect sauna for your needs.

FAQS

Question1：What materials should be avoided when building a sauna?

Answer： PVC, ordinary plastics, and low-heat-resistant acrylic glass are not suitable as core materials for sauna construction.

Question2：Why are tempered glass doors commonly used in saunas?

Answer： Tempered glass is heat-resistant, safe, and has excellent light transmittance. Solid wood doors can also be used to improve overall sealing and reduce heat loss.

Question3：What precautions should be taken when using acrylic glass?

Answer： Avoid placing the sauna heater directly next to acrylic glass, as high temperatures may cause it to deform or melt.

Question4： Will tempered glass in a sauna crack?

Answer： Under normal use, tempered glass will not crack. Cracks are usually caused by human error or low-quality tempered glass.

Question5：What is the appropriate thickness of tempered glass for a sauna?

Answer： Tempered glass is generally 8–10mm thick, though some manufacturers use 6mm. Be sure to check this when purchasing.

Question6： Will there be an odor when using the sauna for the first time? How can it be addressed?

Answer： If plastic materials or sealants are used, there may be a slight odor when first heated. We recommend briefly heating the sauna with adequate ventilation during initial use. The odor will naturally dissipate after repeated use.