Two recent all electric net zero commercial building projects using similar air source heat pumps had very different equipment performance. One met performance expectations and one fell far short. Why? The two buildings are the Energy Futures Group building in Hinesburg, VT and the Suncommon building in Waterbury, VT. The presentation will include 1. Description of buildings and their mechanical systems 2. Detailed measured COP results from one and energy usage vs predicted for the other a. Co-heating test for in-place actual UA (heat loss rate) of the EFG building 3. Simple controls, low cost systems were used in both buildings 4. Lessons learned and what I am now recommending for heat pump system design