Donald J. Heim, president of the Washington Gas Light Co. since 1977, has been elected chief executive officer as well. Paul E. Reichardt, who plans to retire in 1983, will remain chairman of the board, relinquishing his responsibilities as chief executive.

In several related developments, the company announced that Jeremiah K. Hughitt was elected executive vice president in charge of transmission and distribution, gas supply, corporate planning and general services. He was previously vice president for corporate planning, services and rates.

Richard C. Vierbuchen, executive vice president, will assume the new responsibilities of marketing, research, rates and consumer services and public affairs. He was previously executive vice president for non-utility operations. Vierbuchen will also be in charge of the two gas distribution subsidiaries, Shenandoah Gas and Frederick Gas.

Two new vice presidents were elected in the area of utility operations. James W. Freeman, who was formerly director of consumer affairs, has become vice president/marketing and research. Kenneth H. Tracy, who was previously the company's D.C. representative in its communications department, has been named vice president/community projects.

Two appointments in the area of non-utility operations also also announced. Harry L. Ketcham was appointed executive director and vice president of Crab Run and Hampshire Gas Cos. Wayne A. Mills was named executive director and vice president of Davenport Insulation, Universal Insulation, Cellin Manufacturing, Brandywood Estates and Washington Gas Approved Services.