As U.S. policy makers debate a widespread return to the office with continually falling COVID-19 rates, we’re seeing announcements in the news that big names are thinking about a hybrid work return. Google said they’re looking at about 60% of their employees working remote two days a week, while working in the office the other three days. That presents an interesting hurdle for energy efficiency.
In a typical, 9-5, Monday through Friday office, the biggest energy saving opportunity is making sure things are off when no one is there to use them. When a work schedule is predictable like that, it’s very easy to set up your controls to reflect that schedule. With few exceptions, when I visit office buildings – the owners and operators have this well in hand.
The move to hybrid work models in the news resulting from COVID-19, I couldn’t help but think about the repercussions on building energy use. Now, it’s not that difficult if a hypothetical tenant or company decides that everyone will work remote on Monday and Friday — that’s just a defacto “new working weekend” in terms of building controls. You really have to start scratching your head those remote days are flexible. Is Duane working remote on Tuesday? Is Amol working remote on Wednesday and Friday? What about Peter, who finds he’s the most productive when we come in every day? A simple time clock isn’t going to handle this complexity. What can we do?
How to save energy in an office with mixed occupancy schedules
Below you’ll find some ideas for handling an office with mixed occupant schedules.
1. Recommission those occupancy sensors.
In California, occupancy sensors are fairly common in private offices, conference rooms, restrooms, breakrooms, etc. With a trend toward the building being less occupied more of the time, occupancy sensors are going to save more energy than they did in the past — if they’re setup and functioning properly.
Here is my tip for occupancy sensing RCx.
Walk around the building when occupancy is low. Note any occupancy sensor that turns on when you walk by the space – these sensors likely need to be relocated so they don’t have line-of-sight out the door and into the hallway or common areas. Alternatively, the sensitivity may need adjustment, but you need to be sure it’s still able to capture minor motion of the intended occupant. If the lights are on and no one was in the space in the last 30 minutes, it’s an indication that the sensor may be misconfigured and may require replacement.
2. Evaluate building-wide demand control ventilation.
With a reduced occupancy rate on a regular basis, ventilation code will allow us to reduce the ventilation rate based on the number of people and/or the area served. This option is probably one to begin looking at now for implementation in a year or two, after the COVID-19 health concerns have passed fully into the rearview mirror.
To be extra certain you’re providing the appropriate ventilation flow, take a page from Guideline 36 and make sure you’ve got an air flow station in your air handlers to track outdoor air flow and make sure – at least in zones with flexible work schedules – that you use CO2 sensors in spaces with large occupancies (conference rooms, open offices, etc.) and that you have CO2 sensors or integrated vacancy sensors in spaces that are typically all-or-nothing in terms of occupancy (like private offices). Then program your terminal units to reflect to the new inputs.
3. Re-evaluate plug load devices.
With fewer people in the office together at the same time, some appliances may now be oversized (e.g. coffee pots, refrigerators, etc.). Similarly, the absence of people from the office most of the week (e.g. the weekend plus two working days at home) makes plug-load controls even more important. Installing an occupancy sensor or integrating with an overhead lighting sensor could reduce the idle energy draw of monitors, cellphone chargers, task lights – things that often get left on over the weekend. Your old analysis that assumed two-day weekends may need a refresh with updated assumptions for three or four days of weekend-like plug-load demand each week.
4. Reconsider your seating plan based on work schedules.
This opportunity is one that is probably going to get the hackles up of the most people, but it represents a significant opportunity for energy savings. Shuffle your work seating plan to seat people who work similar weekly schedules together. This is particularly relevant for private offices that share terminal boxes. When one private office is occupied, the entire VAV box runs, requiring ventilation, heating, and cooling. If however, all the offices associated with a single VAV box are unoccupied, that VAV box can set back to zero minimum air flow and setback the space temperatures a couple of degrees, further curtailing energy use.
Continually monitor with hybrid work schedules for lasting energy savings
As employees adjust to new schedules in the office, it’s important our building operations do as well. Making the necessary adjustments to accommodate them can save you energy (and money) while reducing associated carbon emissions from energy waste. This is not a one and done effort. So as occupancy hours continue to change, be sure to check-in on your building to be sure it is performing optimally based on conditions. If you have any questions about making your building more energy efficient, contact us anytime.
