This paper describes a method using short-term monitoring to estimate lighting retrofit savings.
This method meets the requirements of Options A and B of the IPMVP (International Performance
Measurement and Verification Protocol, U.S. DOE 1997) This protocol was previously known as the
NEMVP (North American Energy Measurement and Verification Protocol, U.S.DOE 1996a). These
protocols require that energy savings be calculated from the measured reduction in demand with run
hours stipulated (Option A) or measured (Option B).

Using short-term monitoring, the pre- and post-retrofit demand and energy consumption are
recorded to meet the Option A requirements of measuring the demand reduction, including demand
diversity, and through monitoring, the actual run hours are quantified. The short-term measured run
hours are used to determine the stipulated annual run hours. After the retrofit has been performed,
short-term monitoring is again performed to measure the reduced demand, and to verify that the postretrofit
run hours have not significantly changed. For Option B, both sets of run hours measurements
are used for the energy savings estimates.

Two case studies are presented. The first case study used the whole-building approach to
monitoring of the lighting systems. The second case study required a sampling approach, since multiple
end uses were served by the circuit panels. In both cases the savings estimated from the monitored data
was less than the estimates based on the more traditional spreadsheet approach.