States that evaluations of retrofit projects in populations of buildings have shown that only about two-thirds of the savings are being realised. Field monitoring is used to help explain the discrepancies and improve the engineering estimates of savings. Presents a discussion of building monitoring programme design for verifying the retrofit savings. Stresses the importance of monitoring the retrofit effect rather than the end use. Describes an example of the application of building monitoring techniques to a commercial/industrial lighting rebate programme. Results from the first 20 buildings indicated that only 72.8% of the utility-estimated savings were being realised. States the most important factors in improving engineering estimates of savings are an accurate determination of fluorescent ballast types in the pre-retrofit condition and the types of fluorescent fixtures that are present in the building.

KEYWORDS: Monitoring, energy conservation, modernising, buildings, lighting, fluorescent lamps, calculating, commercial, industrial, USA