News From the D.C. Office: Energy-Saving Office Equipment, Part 1 More on the DC Office efficiency up-grade: Lighting, Office Equipment: Part 2

Designing an energy-efficient office involves more than "real estate" features, such as an efficient building envelope, windows, lighting, and space conditioning. In today's offices, the other uses of electricity--mainly for computers and other plug-in office equipment, lunchroom appliances, and conference presentation equipment--can use at least as much electricity as office lighting, typically 30 percent of the total office electricity. Careful selection and operation of this office equipment translates into significant energy and cost savings.

In setting up Berkeley Lab's Washington, D.C. Project Office, we paid close attention to the choice of office equipment and kitchen appliances. As a result, we are currently saving about $1,180/year in energy and paper costs (see figure). During the first two years of operation, we have also learned some important practical lessons about achieving real energy savings while maintaining the performance and services that users expect. The following results are based on spot-monitoring our equipment and operating practices.

Annual cost savings from energy efficiency and duplex printing or copying in the D.C. office.

Computers and LANs. Some of the most important choices to be made in any office, from the viewpoint of both energy efficiency and user requirements, involve personal computers and the local area network (LAN). Our requirements included compatibility with both Macintosh and DOS-based machines, easy access to email and files for staff on travel or working at home, and close linkage with the network at our main Berkeley site. A starting point was to specify computers and monitors with a low-power sleep mode (maximum 30 watts), as required by the EPA ENERGY STAR label. For the Macs, we added an external "Power Key" that automatically shut off the computer and monitor at night after the system backup. Rather than replace one of our older monitors (not ENERGY STAR), we used an external control switch to shut it off when there was no keyboard or mouse activity. However, this system worked only with Windows 3.1 and had to be disconnected when we upgraded to Windows 95. Perhaps the single most effective measure was free: shutting off the two LAN monitors except for a few hours a month when they are needed for specific diagnostic or maintenance tasks. Where email is not appropriate, we use desktop LAN-based faxing wherever possible; this saves paper and electricity, and it improves staff productivity. For a fully occupied office suite, the total electricity savings from computers, monitors, and LAN operations amount to about 9970 kWh/year, a savings of 65%.

Other office equipment. We chose a copier that already meets the ENERGY STAR Tier-2 requirements (scheduled to take effect in July 1997), including two-sided copying as the default mode. This copier also shuts off at night after a pre-set delay and offers a choice of six possible low-power "sleep" modes, with different combinations of standby power and recovery time.

Waiting time for the user is further reduced by a people sensor that starts the warm-up process as soon as one approaches the machine. An on-board toner recovery system recycles toner particles that would otherwise be wasted. By far the most important energy-saving feature is default two-sided copying. While power management features save an estimated 720 kWh ($58) per year, the duplex feature saves another 570 kWh of off-site (manufacturing) energy embodied in the paper and reduces annual paper costs by $190.

Similarly, we chose shared LAN printers (a laser and a color inkjet) and an office fax machine that all meet ENERGY STAR requirements. The laser printer also has a duplex printing option that is easily controlled from the desktop. Power-saving sleep settings on the fax and printers save about 815 kWh ($65) per year, with the same amount in additional paper cost savings from duplex printing.

Kitchen appliances. The refrigerator we selected is an 18 ft³ model with ice maker that uses only 520 kWh, or about 20 percent less than a base-case model meeting the then prevailing (1995) federal efficiency requirements. We have a small storage-type electric water heater, and recently changed the factory settings to lower water delivery temperature by about 20°F. The lower tank temperature reduces standby losses, lowers cooling loads, and eliminates the chance of being burned by hot tap water.

--Jeff Harris and Avis Woods

Jeff Harris
Washington, D.C. Project Office
(202) 484-0883; (202) 486-0888 fax

More on the DC Office efficiency up-grade: Lighting, Office Equipment: Part 2