Like any other real estate broker, Wayne Shenk takes potential home buyers on tours of Washington's neighborhoods. He shows them the schools, the house styles and the local amenities. But even on the coldest winter days, the buyers don't have to bundle up.

Shenk, 32, owner of Kay and Son, is a video buff who has put together a variation on a sound and light show he hopes will stimulate the faltering home-sales industry. He calls the sales tool Welcome Mat and intends to lease it to other real estate firms. It can take prospective buyers on video-taped tours of more than 600 neighborhoods and subdivisions in Maryland, Virginia and the District. Some day, he says, he hopes he can include other major markets.

When buyers come into a real estate office it's often difficult to determine just what they have in mind, said Terry Murchison, executive director of the Lewis & Silverman firm's resale division, the only other Welcome Mat user thus far. "One family wanted a 'colonial,' " she recalled, "but it turned out after looking at the tapes that what they wanted was a 'Williamsburg colonial.' " It eliminated time-consuming trips to see the wrong houses, she said.

Shenk acknowledges that the traditional slide-show-and-photo-book approach might have produced the same result, but the point here is modern technology. "We're trying to entertain -- and educate," he said.

While others in the real estate business have tried the video waters before, Shenk admits, "no one in the U.S. is doing it as complete as we are."

The Welcome Mat program -- trademarked and copyrighted -- is not cheap. The Northern Virginia and Montgomery County packages, each with tours of more than 300 communities, rent separately for $7,200 a year, while the 50-neighborhood District program rents for $5,000. In addition to the neighborhood tours that run two or three minutes each, there are "overview" tapes that provide background information on the three jurisdictions.

Most of the video tours take buyers and agents for a short drive down several neighborhood streets and include a few close-up shots of assorted houses and business centers. Churches, synagogues, buses, hospitals and schools also also shown.

The Vienna Woods tour makes a quick stopover at Wolf Trap's Filene Center; at Arrowhead, a town house development in Montgomery Village, children play in a verdant park while their parents take a few whacks at a tennis ball; in the District's Adams-Morgan section, renovated town houses are seen juxtaposed with the unretouched variety. In Georgetown, the hard sell focuses on busy Wisconsin Avenue and the prestine C&O Canal.

In attempting to sell his video visions to brokers and agents, Shenk pegs his sales pitch on savings. Thanks to Welcome Mat, he says, his firm's gasoline consumption is down 25 percent.

Another new-technology item for the real estate industry is set for introduction here by PRC Realty Systems, a division of Planning Research Corp. of McLean. PRC's Broker Office Support System (BOSS) is a computerized management system with built-in programs that includes a general ledger, accounts payable, word processing and on-line access to a multiple-listing service.

The system, produced at PRC's Dulles facility, is comprised of a microcomputer plus a terminal and a printer. Up to 16 terminals can be run on the single computer. In addition to the software and hardware, the system includes training and a maintenance program.