While houseplants require sunlight to grow, they don’t need UV rays. This window film blocks out UV rays but it doesn’t completely block out every component of sunlight—it still lets in red and blue light. Red and blue light is vital for houseplants. Red light promotes flowering and blue promotes the healthy growth of leaves.(nm) and 400 nm. UV radiation is invisible to naked eye and are broken down into three main bands (UV-A, UV-B, and UV-C). The main source of UV exposure is from the sun, but it is typically limited to the UV-A band, as the earth atmosphere protects us from the harmful UV-B and UV-C rays. Nonetheless, UV The color of plastic can also affect its ability to block UV rays. Clear plastic allows the most UV rays to penetrate it, while black plastic blocks the most UV rays. This is because black plastic has a higher surface reflectivity than other plastic colors. The Age of Plastic. Over time, the ability of plastic to block UV rays decreases.
Low-E Film for Windows. Low-E film, or sun control window film, is a thin plastic layer applied to the inside of a window to improve comfort, privacy, as well as safety and security. Low-E film also saves energy by blocking up to 99-percent of UV rays that ordinarily would have passed into the house.
Poly-carbonates do block UV, not totally but much more so than acrylic. But as other's have commented the UV will degrade it over time. This is the case of all carbon based plastics.
Photosynthetically active radiation (PAR) light transmission varies with the type of film additives. Typical PAR values are: ultraviolet-stabilized film, 88-91 percent, infrared/anti-condensate film, 82-87 percent, infrared/anti-condensate with diffusion, 77-88 percent. Dust, smog and plastic deterioration can also reduce light transmission.