Hot and cold calls come with the territory when managing a commercial building. But don’t ignore this important feedback from tenants and occupants. In many cases, what’s good for thermal comfort is also good for your building’s utility bills.
Hot/cold complaints and thermal discomfort issues are affected by a variety of factors:
- Solar heat gain
- Air temperature
- Average temperature of nearby surfaces
- Radiant temperature or humidity from lighting, a nearby data center or pool, etc.
- Air velocity
Sometimes the source of thermal discomfort stems from a simple problem. Start by checking thermostats; if an occupant changes the thermostat setting within a zone, it can throw the entire HVAC system off. Dampers are another factor; check to see if one is jammed. Lastly, check the system’s diffusers. When an overhead VAV box opens (on a hot, sunny day, for example), the occupants in the office space below should feel the cool air blowing.
If addressing these three factors doesn’t improve the situation, there are other ways to deal with thermal discomfort. (According to ASHRAE Standard 55, thermal comfort is achieved when a commercial building meets the comfort needs of 80 percent of occupants.)
Change HVAC Filters
A U.S. General Services Administration study discovered that using high-performance HVAC filters lowered total HVAC costs by up to 10 percent and improved indoor air quality and movement (conditions that improve occupant satisfaction and comfort).
Consider Displacement Ventilation
This cooling concept introduces low-velocity, cool air at floor level. It uses buoyancy forces generated by radiant heat sources (like people and equipment) to remove heat at the ceiling level instead of mixing it back into the space. Because lighting generates heat, and warm air rises, removing warm air from high in the space and exhausting it can also reduce the amount of cooling needed.
Eliminate Sources of Radiant Heat
Take a look at the number of printers and copiers in your building. If there are some you can eliminate, you not only save energy and reduce interior temperatures, but can also improve employee collaboration. In the same GSA report referenced above, it is recommended that one printer/copier be available for every 25 employees.
Install Low-e Window Film
Low-e window film can improve tenant and occupant comfort year-round. In warmer months, it reduces solar heat gain and keeps heat from entering the conditioned space, improving comfort and reducing utility bills. During cooler months, low-e window film can keep radiant heat inside. Some theories suggest that a connection to the outdoors gives occupants the ability to adapt to a wider range of thermal conditions. Because low-e window film reduces glare without negatively affecting or obstructing views to the outdoors, occupants can leave blinds and shades open and feel a connection to nature.
Chairs with mesh backs and seats can reduce heat build-up and keep occupants comfortable at higher temperatures than seating with cushions. Desks that are open on the sides and backs can also promote air circulation and improve comfort.
How do you handle hot/cold calls?