Glass doors provide views to the outside while allowing natural light into the home. Come nighttime however, they're a window into your home, unless you install curtains or blinds. Simpson Door Company is unveiling another option at the International Builders' Show, a full-lite door with electric glass that can change from clear to opaque with the flip of a switch. Part of its Custom Concept line, the doors will retail for about $2,000, not including installation.

Unless you're a highly-skilled do-it-yourselfer you'll probably need to spring for professional installation, since the high-tech doors are hard-wired to the adjacent wall through a wire that sneaks out of one of the door hinges.

The custom doors are available in any wood species to match the existing decor. They're being marketed as an ideal solution for a patio door, where you want the connection to nature during the day and privacy at night. There are also plenty of interior applications, such as between the master bath and main bedroom or for a home office that you want to be able to close off from the rest of the house at times.

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