The parameter estimate for operating hours per week is positive
and along expected lines—with every 1 h increase in the
operating hours per week, the EPI increases by 1.3 kWh/year/m2.
The longer working hours necessitate operating the cooling systems
and equipment for longer durations and the sign is therefore
positive. Similarly, employment density is also positive and in
agreement with the expected relationship that with increase in
density, which is positively correlated with equipment density,
there is an increase in energy consumption per unit area. The logarithm
of the area has a negative relationship with EPI—as the
logarithm of the area increases, the EPI decreases, indicating that
there is efficiency in scale and larger facilities are likely to be
more efficient compared to smaller facilities. With every increase
in the variable that measures the extent of VFD installation, there
is a decrease in EPI—VFDs tend to increase the efficiency of HVAC
systems.