Baltimore’s thousands of vacant homes aren’t cranking air conditioners during summer heat waves. But some of the city’s near-empty office buildings might be.

The Inner Harbor hit 105 degrees on Tuesday, making it the second-hottest June day in recorded history. To manage the sweltering heat and those costly energy bills, Baltimore Gas and Electric Company recommends setting thermostats to 78 degrees or higher, running fans, closing curtains and blinds and using heat-generating appliances later in the day.

Those moves also reduce stress on the electricity grid — something the region’s grid operator, PJM Interconnection, is so concerned about that it offered to pay the Maryland Stadium Authority tens of thousands of dollars to reduce use at peak times.

But aren’t Baltimore’s large, empty office towers also sucking up energy, some wondered?

More than 20% of the office space in Baltimore’s central business district is vacant, according to a quarterly report from CBRE.

That doesn’t mean entire buildings are empty; most have a few tenants on different floors. And whether the unused floors are cooled depends upon the age of the HVAC system, said Jared Lyles, energy engineer at Maryland Energy Advisors, an energy solutions company.

“I think it’s rare to find one that’s 100% vacant,” Lyles said. And if it’s partially occupied, “usually it will be fully [air] conditioned.”

Most modern office towers are able to control each floor, or even each room, while older buildings may have a heating and cooling system that applies to the whole property.

“It’s going to depend on lease terms, or if it’s vacant, how the owner of the building actually wants to operate it,” Lyles said.

While BGE tries to persuade its residential customers to make adjustments to their usage during heat waves, the utility company doesn’t provide a “blanket recommendation” to its commercial customers, said BGE Spokesperson Richard Yost in a statement.

“BGE’s work with commercial customers focuses on energy efficiency and leveraging our rebate programs to reduce their upfront costs associated with operations,” Yost said.

The utility company said it doesn’t promote thermostat or light setting recommendations. Instead, it pushes for “lighting and thermostat automation technologies to ensure the most efficient use of energy.”

It can be expensive to run air conditioning for commercial properties. Some property owners try to make adjustments on hot days by precooling the building before 2 p.m., when peak hours typically start, and turning up the thermostat to a higher temperature until around 6 p.m., Lyles said.

While it sounds ideal to completely turn off the AC or heat in a vacant office, sweltering heat and frigid cold can affect the paint or lead to burst pipes.

“The best practice is to turn those systems down so they’re not running on full blast and they’re not conditioning for people,” Lyles said. “They’re just keeping the air circulating and keeping the building from being damaged.”