In the United States, heat pumps and air conditioning systems must meet federal energy efficiency standards before they can be legally sold or installed. These standards are designed to ensure products are energy-efficient, accurately tested, and properly labeled for consumers. For a 12,000 BTU heat pump, the minimum required efficiency rating is 13.4 SEER2. SEER2 is the official measurement used to show how efficiently a system performs under real-world operating conditions.