Combatting Low Occupancy in Office Facilities

Remote and hybrid work schedules appear to be here to stay in many office environments.  If you lease your office space, hopefully you can “right-size” your space requirements so that you can save cost the next time your lease is due for renegotiation.  However, what happens when you’re on the other side of that equation, as a property owner that leases office space, or someone who owns office facilities for your own business or school?  Are you doomed to pay the same utility and maintenance costs for partial occupancy? Can you just turn off systems? Can you close off ventilation systems? Can I change system temperatures to save some money?

While you will likely still be on the hook for maintaining the entire space, that doesn’t mean that there aren’t adjustments that can be made that maintain the facility in its current condition, maintain indoor air quality, reduce operational costs, and increase life-expectancy of your equipment.  Temperature setbacks, ventilation adjustments, equipment adjustments, revised maintenance practices, controls changes, and coordinating work schedules can be employed to meet these goals.  Not only will these strategies save you money, but they can also reduce your operational carbon footprint, which is at the forefront of today’s environmental discussions.

Temperature Setbacks – It’s unlikely that the occupants would be happy about working in warmer-than or cooler-than-standard spaces, but coordinating work schedules to maximize the amount of unoccupied time in your facility can reduce operating costs.  This can be done on a system-wide level if you only have wall thermostats with a timeclock function or can be done on a zone-by-zone basis for facilities with a DDC (Direct Digital Control) control system.

Ventilation Adjustments – It’s not a great idea to adjust outside air based upon a perception of occupancy, however, with the annual average cost of outside air is approaching $5 per cfm (cubic feet per minute), calculated adjustments may be the best bang for the buck.  Modern ventilation standards, such as the International Mechanical Code and the industry-standard, ASHRAE 62.1 require new facilities to provide ventilation based upon occupancy and airflow per square foot.  This approach makes sure that CO2 (carbon dioxide) produced by occupants and VOCs (Volatile Organic Chemicals) produced by materials in the space are adequately ventilated.  Before making adjustments to the ventilation rate in your facility, a ventilation study, followed by an air-balance by a qualified contractor should be performed.

Equipment Adjustments – Can you slow down a fan or turn it off?  The answer is maybe. Turning off a restroom fan for an extended period of time like days, weeks or months, is not advisable.  Slowing down a constant volume air-handling unit may be done if it is cooled by chilled water but is probably not possible if cooling is refrigerant-based.

Revised Maintenance Practices – Lower occupancy, less run time, and the same filter area means you should be able to extend filter replacement time.  However, water systems will still need the same amount of care as a fully-occupied building.  In this case, knowing where you can cut back is not as important than knowing where you can’t.

Controls Changes – If you have a DDC control system, or even a smart controller on a rooftop unit, you may be able to use occupancy sensors, CO2 sensors, or VOC sensors to control operation, control temperature, or adjust ventilation, all to reduce operational costs.

Understanding when and where to make these changes can reduce operating costs, extend equipment life, continue to provide a safe, healthy environment, and avoid making a costly mistake that ends up in mold, equipment, or system failure.  Having the right advisor can make all the difference.  Barton Associates has 55 years of experience advising clients on not only keeping their facilities running but making buildings work well throughout the United States and around the world.   If you would like to see if you can reduce your operational costs during partial occupancy, give us a call or email.  If you have questions on this, or another technical topic, please do not hesitate to contact Stephen E. Oskin, PE, LEED AP at (814) 880-6070 or

Leave a Comment