The City of Berkeley is soliciting written proposals from qualified firms or individuals to perform Whole-building Performance testing on three separate residential-scale buildings, and complete energy efficiency improvements using the performance-based standards set forth by RESNET and used in EPA Home Performance with Energy Star program. A loading-order approach that eliminates lost opportunities is preferred. As a Request for Proposal (RFP) this is not an invitation to bid and although price is very important, other factors will be taken into consideration.