Just as sunscreen protects our skin from the sun's damaging ultraviolet (UV) rays, window treatments protect our room interiors and add to the lifespan of valuable possessions. Virtually every Hunter Douglas product filters out at least 75% of the sun's harmful UV rays when installed over double-glazed glass windows. Many of our products provide even greater protection, up to 99%, when fully lowered and with slats, vanes or louvers in the fully closed position. The rating of Good to Excellent to Superior for this product will partly depend on the fabrics and product features you choose and whether your window covering is opened, closed, raised or lowered.