More than 1,000 tornadoes touch down in the United States each year, according to the Weather Channel, ripping through communities with wind speeds of up to 318 mph. Many homeowners in tornado-prone areas of the country are seeking protection by adding safe rooms and storm rooms.

Severe storms aren't the only reason for the increased interest in these rooms, however. Threats to personal safety, such as terrorism and burglary, have many homeowners on edge.

Storm rooms and safe rooms are designed to meet different threats. There are many manufacturers of prefabricated storm rooms and safe rooms, and some -- such as RemagenSafeRooms, KeepSafe, New Necessities, and Zytech Engineering -- make both. Both types of units are referred to as safe rooms by some manufacturers, but distinctions are made between models based on the level and type of protection required.

Most manufacturers agree that the most practical installation is to finish a home's storm room or safe room to serve a dual purpose, such as doubling as a master bathroom or closet. "Our design parameters are geared toward having it be a functioning room within the house," says Jim Ranson, product manager for DuPont Advanced Fiber Systems, about DuPont's StormRoom with Kevlar.

Manufacturers recommend locating the room near the main living or sleeping quarters for fast and easy access. However, storm rooms can be just as effective installed in basements or garages.

"Usually I tell homeowners that they work well in garages," says remodeler Jack Atkins, with Premier Homes of Crossville, Crossville, Tenn. "There have been a few people I've talked to who want their bedroom closets to be modified into safe rooms so they can access the safe room within a few seconds."

Because there are no current standards for safe-room and storm-room construction, many manufacturers voluntarily submit their units for testing and engineering-design analysis by the Wind Engineering Research Center of Texas Tech University. The Federal Emergency Management Agency's National Performance Criteria for Tornado Shelters detail the standards that storm rooms should meet.

Prefabricated safe rooms and storm rooms offer a variety of installation options. If left unfinished, and depending on their location in the home, most can be installed in a day. Some units are modular and are delivered in pieces to permit simpler retrofitting.

Check out this DuPont Storm Shelter