Listed a year ago for more than $3 million, the authentically Virginia colonial Potomac House on six acres near Merrywood on Chain Bridge Road now is available for $2,225000. Rodney Dillard of Illustrated Properties and Joan G. Day of Washington and Boteler-Day of Middleburg now are trying to sell the three-storey manor house with 20,000 square feet of living area. It was built originally for Louis Pomponio and now is owned by Young & Simon, a independentinsurance firm in Georgetown. To show off the property that has a wine cellar that doubles as a bomb shelter with a concealed emergency escape tunnel, the house will be the scene of a fund-raiser for John Warner, the Republican candidate for a Senate seat from Virginia. He has promised hosts Dr. Max and Madeline Zung to bring his wife to the event scheduled Oct. 14.

Philip L. Sheridan, general and managing partner of Concord Homes which has opened the Sutton Oaks town houses in the Vienna area, said that he got the idea for exposed brick walls and skylights from his own experience in living near DuPont Circule. "And the public has also reacted positively at our suburban location," he added.

W.C. and A.N. Miller, which dates back to 1912, is completing 34 condominum town homes and apartments on a three-acre tract in the 4800 block of Sangamore Road in Sumner. The site is near the Little Falls Shopping Mall and the Sumner Village mid-rise condominium community. Also, the Miller firm has cleared a triangular site on upper Massachusetts Avenue, near Fordham Road and Van Ness, for 24 town homes and 11 detached houses. Construction will begin before Thanksgiving. Meanwhile, the Miller firm has moved into Virginia for the first time and will start 46 single houses on half-acre lots on 23 acres facing Beaulah Road in suburban Vienna.

Edward and Joan Luedtke now live in a still fairly new house that he built in the Broadwater Estates area of Oxon Hill. The computer specialist and electronics technician said that he did most of the work on the 2,300-square-foot house and his wife helped with the painting and sanding. The Luedtkes are proud of their teak floors.

SHORTLY: HOUSING magazine has reported that the HOW (home owner warranty) progran of the National Association of Home Builders, now covers more than 10,000 building firms and 165,000 houses built in recent years. But two of the nation's biggest builders that operate in this area, Ryland the Ryan Homes, are not in the program . . . Two recent studies on electrically powered attic fans showed no difference in energy consumption in electrically air conditioned houses with or without the attic fans . . . The Homearama showing of 22 new houses at one location in Cincinnati recently attracted 100,000 persons who paid $2 to view the houses done by different builders. Serving bratwurst and beer helps to make it a family-style event in the riverfront city where Pete Rose grew up and stayed. In the 1960s there were some central home shows of different builders in this area . . . Developer Marvin Weissberg said that the old generator from the flour mill being redone into an office-apartment complex in Georgetown was donated to the Smithsonian "but we had to deliver it." His Flour Mill development is expected to be ready for affluent condo apartment dwellers and office space tenants late in 1979.