How to Choose Sauna Glass: Shading Test

In today’s sauna-loving society, people not only seek the health benefits of saunas but also make intentional choices when selecting their ideal sauna rooms. Alphasauna, a leading sauna manufacturer in China, has gathered market data showing that people prefer sauna rooms with glass walls over those with only glass doors. But why is this the case? What impact does a sauna room with glass walls have overall?

To help you find the perfect sauna experience, Alphasauna carefully evaluates and tests the shading degree of sauna glass, ensuring the best sauna room selection for your needs.

The Role and Importance of Sauna Glass

Sauna glass is not merely a decorative accessory; its material, design, and craftsmanship directly impact safety, functionality, and the user experience. First, sauna glass strikes a balance between privacy and transparency. Second, the thermal insulation properties of different types of glass help reduce heat loss and maintain the sauna’s temperature. Finally, a sauna glass wall eliminates the feeling of claustrophobia, creating a more open and aesthetically pleasing space.

Types of Sauna Glass

Tempered glass is the most commonly used type in saunas. It offers high strength, heat resistance, and excellent safety. Even if broken, it shatters into small, blunt-edged particles, minimizing the risk of injury. However, once tempered glass breaks, it cannot be repaired and must be replaced entirely.

The second type is polycarbonate (PC) board, which is primarily used for sauna ceilings. It allows ample light into the sauna, can be bent into various shapes, and offers flexibility in design.

Lastly, acrylic glass is often used for panoramic sauna windows. It serves as an alternative to traditional PC boards and tempered glass, with advantages in weight and plasticity, making it an excellent choice for unique designs.

Differences Between Materials

These three materials are commonly used in sauna construction, but they have distinct characteristics and are suitable for different applications.

Tempered Glass

Heat resistance: Withstands temperatures of 250°C–300°C.

Durability: Scratch-resistant and maintains clarity over time.

Drawbacks: Heavier than other materials and must be fully replaced if broken.

PC Board

Strength: Highly impact-resistant and difficult to break.

Lightweight: Easy to install and shape into custom designs.

Drawbacks: Prone to surface scratches and may yellow over time. Requires regular cleaning.

Acrylic Glass

Weight: 50% lighter than ordinary glass, making installation easier.

Flexibility: Ideal for panoramic sauna designs.

Drawbacks: Low heat resistance（80℃-90℃）, easily scratched, and vulnerable to chemical corrosion. Avoid using strong acids or alkalis when cleaning.

Each material has its strengths and is chosen based on specific sauna design requirements.

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Alphasauna Manufacturer Sauna Glass Shading Test
Next, Alphasauna conducted a shading test on 8mm tempered glass (transparent, brown, black), PC board, and acrylic glass (brown, transparent) to help customers understand the differences between these materials and select or customize a sauna room that best suits their needs. The test was performed using two different methods: the paper flashlight test and the sunlight projection test.

Sunlight Projection Test Method:

This test demonstrates the shadow effect of tempered glass under direct sunlight. As shown in the picture, sunlight completely penetrates transparent glass, resulting in an almost invisible shadow, with no shading effect. Next, brown glass creates a yellowish-brown shadow, the brightness is reduced, and it offers some shading effect. Finally, black glass produces the darkest projection, with the lowest light transmission and the strongest shading effect.

Secondly, transparent acrylic glass, like tempered glass, has high light transmittance. Brown acrylic glass, however, provides greater light shielding under sunlight, with a typical light transmittance of 30%–50%. The 8mm thick acrylic glass further enhances its light-blocking properties, making it more suitable for open sauna rooms or those requiring a certain level of privacy. Finally, PC board also has relatively strong light transmittance, allowing light to pass through as clearly as tempered glass.

Flashlight Test Method:

As shown in the figure, the light transmittance of transparent, brown, and black tempered glass differs in a dark environment. First, transparent glass creates a brighter light on white paper with a lighter shadow, offering strong light transmittance. Second, brown glass projects a yellow-brown hue, and the brightness of the flashlight passing through the glass is slightly lower, providing some light-blocking effect. Finally, black glass has the lowest brightness, the dimmest projection, and a stronger light-blocking effect.

In a dark environment, transparent acrylic glass exhibits strong light transmittance with a softer glow. Brown acrylic glass also has high transmittance, but some light diffuses, projecting edges less sharp than tempered glass. Finally, the PC board offers similar light transmittance to transparent tempered glass, allowing light to pass through easily, even in low-light conditions, ensuring ample illumination in the sauna room.

Conclusion

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Through the above tests, we have determined that transparent tempered glass, PC board, and transparent acrylic glass offer high light transmittance, clear projections, and unobstructed visibility while enjoying the sauna, whether during the day or at night. In contrast, brown tempered glass and brown acrylic glass have lower transparency, providing increased privacy while still allowing some light to pass through, making them ideal choices for outdoor saunas.

How to Choose the Right Sauna Glass

Based on the sauna glass shading tests, we know that different materials provide varying levels of shading. Therefore, you can choose between tempered glass, PC board, and acrylic glass based on your specific preferences and needs.

Tempered Glass

Tempered glass is commonly used for glass doors and walls in saunas. This type of glass gives the sauna a modern and sleek appearance. Unlike traditional closed saunas, glass walls allow you to blend in with the surrounding environment, increasing the sense of space inside the sauna and reducing feelings of claustrophobia, making the sauna experience more relaxing. When choosing tempered glass, consider the following points:

If you prefer more natural light, you can choose transparent tempered glass, allowing you to observe the external environment while enjoying the sauna.

If you want to maintain some privacy without completely blocking the light from outside, brown tempered glass is a good option.

If privacy is a top priority for you, black-tempered glass provides excellent privacy protection.

PC BoardM

The PC board is made of a curved transparent structure and is often used for the ceilings of outdoor sauna rooms. It provides excellent natural lighting while offering good heat insulation, reducing the need for artificial lighting. If you are looking for lightness and impact resistance, a PC board is a great choice.

Acrylic Glass

Acrylic glass is typically used in unique designs and is often seen as panoramic glass at the back of sauna rooms. It provides a certain degree of privacy while offering a wide field of vision. The selection method for acrylic glass is similar to that of tempered glass. Transparent acrylic glass offers the best light transmittance, while brown and black acrylic glass is ideal for semi-open saunas and sauna rooms where privacy is a priority.

Why Choose Alphasauna to Buy a Sauna Glass Room?

There are many suppliers for sauna rooms, but why choose Alphasauna? First, in terms of materials, most suppliers on the market use 6mm glass, while we use 8mm glass, which is safer. Although the difference is only 2mm, 8mm glass offers stronger strength and impact resistance. It is less likely to break when subjected to external forces, and even if it does break, it will shatter into smaller, blunt-edged particles, making it ideal for sauna rooms.

Additionally, Alphasauna offers a variety of saunas with innovative designs, ensuring high quality while providing users with more options to choose from.