The Northwest Energy Efficiency Alliance (NEEA) contracted with Ecotope, Inc. and Cascade Engineering Services, Inc. to conduct a laboratory assessment of the Stiebel-Eltron Accelera 220 E heat pump water heater (HPWH) for northern climate installations. Cascade Engineering evaluated the Accelera 220 E using a testing plan developed by Ecotope to assess HPWH performance.