Residential Energy Audit Act of 1979 - Amends the National Energy Conservation Policy Act to require a residential building owner offering his building for sale to make a copy of the energy unit audit report on such building available to the purchaser, if the building is served by a utility offering a residential energy conservation program, and is financed by any institution the deposits of which are insured by a Federal agency. Prohibits any such financial institution from providing financing for the purchase of a residential building served by such a utility unless such institution has received a current energy audit report on the building.