The U.S. Environmental Protection Agency (EPA) and Department of Energy (DOE) are tightening their standards for geothermal heat pump (GHP) systems under the federal ENERGY STAR Program. Stricter program tiers will impact how consumers of GHPs can claim the 30% federal tax credit for residential GHP installations, and the agencies have clarified questions about date of manufacture vs. date of installation in claiming the credit. ENERGY STAR is an international standard for energy efficient consumer products originated during the early 1990s in the United States. Products that have earned the ENERGY STAR designation meet strict energy efficiency guidelines set by the EPA