Can I Get a Tan Through a Window?

Glass doesn't offer full protection from the sun.

It may be tempting to think you are safe from the harmful cancer-causing rays of the sun while sitting in your conservatory, or by a window, but it isn't so straightforward. A window does not offer you 100 percent protection.

Ultraviolet Light

There are two types of Ultraviolet (UV) light that can reach the earth from the sun--UVA and UVB. UVA is long-wave, and UVB short-wave.To some degree, both of these rays can reach you through glass.

Tanning

UVA is the light that makes you tan. A tan results from injury to the DNA, causing the skin to darken to prevent any more damage. UVB causes sunburn by damaging the initial layers of skin. Both UVA and UVB can cause damage to the skin and eyes and cause cancers such as basal cell carcinoma, squamous cell carcinoma and melanoma, even through a window.

Filter

Glass can filter out some UVB, but not UVA, so you can get a tan and a sunburn through a window. Although it offers more protection than nothing it isn't perfect, and you should still use sunscreen.

Cancer

UVA radiation is not blocked, so even if you don't tan you may have premature aging from sitting by a window regularly, and may even get skin cancer. Skin cancer is the most common of all cancers in the United States, and one in five people will develop some form of skin cancer.

References

• Skin Cancer: Skin Cancer Facts
• Skin Cancer: Understanding UVA and UVB
• How Everything Works: Windows and Glass Home Page
• The Weather Prediction: Sunburn/Tanning Myths Exposed

Resources

• FDA: Sun Safety, Save Your Skin