The lights are on but nobody's home
Eugene Water & Electric Board staff recently analyzed typical daily electric use
from 15-minute meter data for 91 commercial buildings in Eugene. The average April
weekday profiles for 17 office buildings and 20 retail buildings are shown in Figure
1.
The results are in and the after-hour electric use is surprisingly high. In fact,
if the high-load is compared to the low-load, typical after-hour office use is in
the range of 35-60 percent of the occupied value. Retail building load is typically
30-60 percent when empty.
That means a lot of electricity is being used at night when nobody is there, providing
an opportunity for significant savings on electric costs. Strategies that can reduce
unoccupied electric use include:
- turning all lights off at night except for limited security lighting.
- coordinating custodial work so only the area being cleaned is lit.
- turning off computers when leaving for the day, or have information services install
automated power management software on your network.
- making sure programmable thermostats are set properly to set back temperatures at
night.
For more ideas on saving energy in your building, check out the Energy Smart Operations
booklet online at www.eweb.org. If you want to subscribe to on-line energy profiling
data for your building, call us about our "Powerline" service. The full study as
presented at ACEEE in August 2004 is also available on-line.
