After installing energy conservation measures (ECMs), Energy Service Companies (ESCOs) often determine the energy savings resulting from the project and present the savings results to their customers. A common way to
calculate energy savings is to measure the flows of energy associated with the ECM, and then to apply spreadsheet calculations to determine savings. For example, a chiller retrofit would might require measurements of chilled water supply and return temperatures and kW. The benefit of this approach is that the ECM is isolated, and that only energy flows associated with the ECM itself are considered.
This method is described as Option A or Option B in the International Performance Measurement and Verification
Protocol (IPMVP). Table 1 presents the different options. Option A requires some measurement and allows for estimations of some parameters. Option B requires measurement of all parameters. In both options, calculations are done (typically in spreadsheets) todetermine what energy savings. Option C uses utility bills to determine energy savings.