The National Capital Heating and Air Conditioning Association will meet Wednesday evening at the Fairfax Stove in Fairvax, City. Robert Pierson will discuss solar energy and heat pumps.

Marjorie Leming, wife of builder-developer Ernie Leming, has announced plans to form an auxilliary to promote education and friendship within the Washington Home Builders Association.

The Carey Winston Co. has announced that the 100,000-square-foot Yorktown 50 office building at 8316 Arlington Blvd. is fully leased. The site is near the proposed site of the new Mobil Oil Corp. headquarters in Fairfax County. The Winston firm is currently handling the leasing of the Unibank building in Rockville.

Gordon Cavanaugh has been nominated by President Carter to be adminsitrator of the Farmers Home Administration, which operates a $3 billion housing program in small towns and rural areas. Cavanaugh has been executive director of the Housing Assistance Council.

The Mortgage Bankers Association of Metropolitan Washington will hear home builder James P. Ryan, president of the Ryland Group, at a meeting to be held at noon on May 31 at the Mayflower hotel. Ryan will discuss problems in the home building industry.

Trans-American Real Estate Exchange, a national real estate referal service, based in Salt Lake City, has named Snider Bros., Inc., its representative in Montgomery County and the District.

Robert G. Depew has been named project manager for Cadillac Fairview's Washington Industrial Park in Lanham. The 200-acre industrial park was opened in 1975.