Saving energy in unoccupied buildings

Panel: 7. Policies for a green recovery in the buildings sector

This is a peer-reviewed paper.

Authors:
Alan Meier, Lawrence Berkeley National Laboratory, USA
Kurt Kornbluth, Energy and Efficiency Institute, UC Davis, USA
Sadia Gul, Energy Graduate Group, USA
Joshua Morejohn, Facilities Energy & Engineering, USA

Abstract

This paper describes a means of reducing the energy use of miscellaneous electrical loads (MELs) in buildings during times when nobody is in them. Reducing energy use in “vacant” buildings is an attractive target for policy initiatives because nobody is present to complain about reduced services. At one university campus, the buildings were fully vacant about 29% of the time. These times mostly corresponded to nights, weekends, and holidays (and, more recently, pandemics). About 24% of the buildings' electricity use occurred during these times, even though no people were in the buildings. The electricity consumed by uncontrolled MELs appears to be responsible for much of this consumption.

This study investigates opportunities to save electricity in buildings during these unoccupied periods. We also identified many devices that are presently not fully controlled and could be operated at much lower power levels during periods of total vacancy. Many of these devices can be modified to greatly reduce their energy use during vacant periods, yet quickly recover to normal operation if somebody enters the building. The energy savings potential ranged up to 90% during vacant periods.

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