If you’ve ever put an upholstered sofa in front of window or noticed a rug getting more and more faded every year, you know what  sunlight can do to your stuff. It can even cause wood floors to lighten or darken and bleach the art and family photos on your walls.

Not only does sun damage make your home less attractive, it can also cost you money by forcing you to replace rugs and furnishings more often.

The major culprit, by far, is the sun’s ultraviolet (UV) rays, which account for 40 to 60 percent of damage, according to the National Fenestration Rating Council, a nonprofit organization that evaluates windows for energy efficiency. Other causes include artificial light, heat and humidity.

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Obvious measures, such as keeping your curtains closed and the blinds lowered, can help. But if you enjoy being able to see out of your windows during the day—and don’t want to feel like you’re living in Castle Dracula — you might want to consider other measures.

Your first line of defense is the windows themselves. If you’re building a new home or replacing your old windows, ask about laminated or low-E coated glass, available from many major manufacturers. Some window makers claim their products can filter out as much as 99 percent of  harmful UV rays. They may cost more than conventional windows. 

If you’re happy with your current windows, another option is window film. These films, which have improved in recent years, can serve a number of purposes, including making windows resistant to breakage, keeping rooms cooler, and filtering out UV light. If sun damage is your primary concern, focus on UV protection. Many films claim to block 99 percent of UV rays, and an independent test of several major brands in 2010 found similar results.

You can hire a professional to install window film or buy film at a home improvement center and do it yourself. One additional benefit: You’ll also be protecting your family from some  skin-damaging UV radiation, according to the Skin Cancer Foundation.

Other approaches

There are a number of other measures you can take to shield your precious possessions from sun damage, whether or not you install special windows or window film.

For paintings and photos: UV-blocking “glass,” which is often actually acrylic, can filter out harmful rays. Hanging artwork out of direct sunlight is also smart. For anything valuable or irreplaceable, consider having a good copy made and hang that instead. That’s one of the artwork preservation tips from the Library of Congress, whose archivists have some experience in these matters. You can always bring out the original for display on special occasions.

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For rugs: Spray-on protectors are one option, though their effectiveness is a matter of some debate in the carpet community. Window films will also provide protection, as will rotating your rugs periodically. That way, if they’re going to fade, they will at least do it more evenly. Before discarding a rug simply because of fading, check with a carpet store or professional carpet cleaner, which may be able to restore the rug to its original color or something close to it.

For wood floors: Sunlight darkens certain kinds of woods and lightens others. Some new wood laminate floors have built-in UV-inhibitors, which, as their name implies, can slow the rate of sun damage but won’t stop it entirely. Try to move your furniture around now and then to promote more-even, less-obvious floor fading. 

For furniture: Lighter upholstery fabrics will generally show less fading, and some leather finishes are more fade-resistant than others. So it’s worth asking about colorfastness when you’re buying a new piece, especially one you expect to get a lot of sun. Leather can also be re-dyed and restored, though obviously it’s cheaper to prevent the damage in the first place.

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For more information about the types of things that are more (or less) prone to  sun damage around your home, the Library of Congress offers these enlightening guidelines. The Smithsonian Institution, keeper of the nation’s historic artifacts, also has some useful tips for protecting your personal treasures. 

Greg Daugherty is a longtime personal-finance writer and a former senior editor of Money magazine.