Downtown office occupancy is still down 83%, as workers continue to work from home during the COVID-19 outbreak. But despite low occupancy, energy use in office buildings in Oakland, the Strip District and Downtown fell only 4% from pre-pandemic levels in 2020, according to a Green Building Alliance report.
The report found that even when a building’s occupancy is low, not much changes in terms of how much energy it needs to operate.
“It doesn’t matter if there are people in the building or not, really,” said Chris Cieslak, the senior director of the Pittsburgh 2030 District, an energy-reduction and reporting initiative in which nearly 500 Pittsburgh buildings participate. “The building becomes a living, breathing body that you have to take care of, whether it’s during a pandemic or not.”
About half of commercial building energy use is from heating, cooling and ventilation. But unless a building is completely unoccupied and “mothballed,” or taken out of use, the amount of heating and cooling it needs does not change.
“If you’ve got 10% of the folks in the building, you still have to heat and cool it and ventilate it,” Cieslak said. “You have to take care of the people — the skeleton crew — that is coming into that building. They still need to have good indoor air quality. They still need to have a reasonable temperature to work in.”
While low-occupancy office buildings have likely used less electricity to power lighting and computers, some may be using more to improve indoor air and decrease the risk of COVID-19 transmission. Some of these strategies include opening air dampers to allow more outside air into a building and using dense MERV-13 air filters, both of which increase the amount of energy needed to condition a building.
It is not clear when Pittsburgh office buildings will be fully occupied. During the summer, occupancy rates increased slowly, at the rate of about 1 percent of pre-pandemic previous levels per month.
Cieslak says it may make sense in the future to use building automation to shut down parts of low-occupancy office buildings under pandemic circumstances, such as “mothballing” an unused conference room.
“In the back of our minds — I don’t know if this is realistic or not — if you’re going to have a pandemic once every 10 years, and it’s going to wipe out your occupancy for two years at a time, then yes, maybe it does make sense to have your buildings be able to be expanded and contracted every single time that happens,” Cieslak said. “It will take a lot of money to do that.”