can uv light get through double pane windows

Can UV Light Get Through Double Pane Windows?

Can UV light get through double pane windows? Sunlight can be incredibly beneficial to us. It can help to improve sleep, reduce stress, maintain bone health, and even strengthen your immune system. But, it’s possible to have too much of a good thing. If you’re anything like me, you’ll know to take steps to protect yourself from UV rays in open spaces. But, a lot of people don’t realize these rays can just as easily pass through our windows into our homes, too. Today, I’ll take a closer look at whether double-pane windows can help to protect you from UV light exposure, and other ways to prevent UV rays from entering your home.


What Is UV Light Anyway?

The UV (ultraviolet) region of the radiation spectrum consists of 3 different divisions:

  • UVA
  • UVB
  • UVC.

UVA (315–400 nm)

This makes up the majority of what reaches the Earth’s surface from the sun. It’s completely blocked by laminated and green glass and by windows with sunlight-control films applied to them. According to the International Ultraviolet Association, ordinary glass transmits about 74% of UVA radiation. UV-A penetrates further into the skin, potentially resulting in premature aging and wrinkling.

UVB (280–315 nm)

UVB is much more damaging than UVA, but most of it is absorbed by the Earth’s ozone layer. It’s completely blocked by nearly every type of ordinary glass, including double pane glass. UV-B is absorbed by the upper layers of the skin, causing sunburn.

UVC (100–280 nm)

The ozone layer entirely absorbs UVC. You might only encounter it from artificial sources like mercury discharge tubes and arc welders. The Earth receives mainly UVA and UVB radiation. Research shows that UVA comprises 95% of the UV rays that reach the Earth, and that UV radiation is related to around 90% of cases of skin cancer.

So, Can UV Light Get Through Double Pane Windows?

Typical double-paned window glass is used in houses and offices to reduce UV exposure. The real question, however, is; can UV light pass through double-pane windows? Only UVA can pass through glass. UVB has a short wavelength, so window glass does not transmit it. UVC is absorbed by the atmosphere and does not reach our windows.

Double-paned windows use transparent glass to transmit visible light and absorb nearly all UVB. However, glass does transmit UVA, which may cause cancer-causing genetic alterations and skin damage.

can uv light pass through double pane windows

How Far Can UV Light Penetrate Through Double Pane Windows?

UV light can penetrate several feet through double-pane windows. These are the most common type of windows you see in households and offices. However, the amount of UV rays penetrating through the windows is not much compared to what you’ll encounter in open spaces.

What Glass Does Not Block UV Light?

Studies show that thin and colored ordinary glass does not block UV light effectively. Factors that can influence glass’s UV protective qualities include:

  • Glass type
  • Color
  • Interleave between glass
  • Glass coating

Smooth ordinary glass transmits the maximum dosage of UVA radiation (74.3%). Thick, laminated glass completely stops UV rays from penetrating through the window. Differently colored glasses block UV light to varying extents. Blue glass transmits the most radiation (56.8%), while green glass completely stops UVA radiation.

How To Stop UV Rays Through Windows

Besides impacting your health, UV light can also severely affect your furniture. It can cause premature color fading, and can warp and split floorboards. So, there’s a lot of incentive to prevent UV rays coming into your home. Here are a few ways you can help protect yourself and your house from damaging UV rays.

Tinting Windows

Window tinting means applying a thin laminate film to window glass for UV protection. It causes UV rays to bounce off the window glass and travel back toward the atmosphere, keeping you safe.

You can think of UV window tinting as a transparent filter that blocks the harmful effects of direct sunlight yet allows the beneficial ones to pass through your windows. Since the films are non-metallic, they offer a clear view through the window while providing maximum protection.

Installing Solar Screens

Solar screens can block between 65 and 95% of the sun’s heat and dangerous UV rays. They are made of PVC-coated polyester. The correct installation of solar screens requires a small air gap between the screen and the glass. This stops heat from striking the glass and passing through it. The screen keeps the glass from heating up by reflecting heat and UV rays outside and away from the window.

The screen slightly reduces visibility. However, it is essential to note that window films do not stop heat from hitting the surface of window glass, but solar screens do.

Window Blinds

When completely lowered or closed, specialized solar shades or blinds can help block up to 99% of UV rays. Blinds made of translucent fabric can still block at least 75% of UV radiation without reducing the amount of light in your house. Solar blinds soften direct sunlight while illuminating your room and lowering your demand for interior lighting.

Can You Burn Through Double-Pane Windows?

Double-pane window glass completely blocks all UVB and UVC radiation. Since burning and tanning are the effects of direct exposure to UVB, you can not burn through double-pane window glass. But, you can still be vulnerable to UVA, which can cause premature aging.

How Can You Tell If Your Window Glass Is UV Protected?

The right way to tell if your window glass is UV protected is with a radiometer that monitors UV transmittance. The radiometer correctly measures the amount of UV that passes through your windows. A low transmittance reading indicates your window glass absorbs most of the UV rays and is UV protected.

Can UV Light Get Through Double Pane Windows? The Takeaway

Sunlight contains harmful UV rays that can potentially damage your skin, resulting in premature aging, discoloration, sunburn, and even cancer. Double-pane windows block UVB due to their short wavelength but transmit UVA up to several feet through the window. Thin and colored window glass doesn’t effectively block UV rays, but thick, laminated glass can block up to 75% of harmful UV light.

A radiometer that measures UV transmittance can correctly calculate the amount of UV rays that make it through your windows. You can help stop UV light from penetrating through double-paned windows by tinting window films, installing solar screens, and adding window blinds.

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