The Northwest Energy Efficiency Alliance (NEEA) contracted with Ecotope, Inc., to review the Alliance Cost Effectiveness (ACE) model for the Heat Pump Water Heater program. For the report, Ecotope focused on reviewing NEEA staff’s proposed method to aggregate Residential Building Stock Assessment II data so that the savings forecast reflects new “alternate” savings weights. These “alternate” savings weights were developed to better represent the population at the sub-regional level. This memo includes recommendations by Ecotope to correct and refine NEEA’s proposed methods pertaining to 1) assumptions about water heater installation location and; 2) limiting heating type extracts to homes with electric resistance water heating.
