Human behavior and interaction with the building space plays a critical component in achieving holistic sustainability. Desired gains in energy efficiency can only be achieved and sustained if the occupants and HVAC systems are working in tandem.

Occupants have one main concern when it comes to HVAC: comfort. When a space is uncomfortable, you will often see building occupants bringing in their own space heaters, humidifiers, fans and other equipment that adds to the overall building energy load. These devices are a form of system “controllability,” but not the type that is best for energy efficiency. Occupants can also impact HVAC systems by leaving equipment on unnecessarily, creating extra waste heat. Strategies to reduce the loss of conditioned air, like revolving doors, are often bypassed. Operable windows are often left open when outdoor conditions are unfavorable. To improve the effect of occupants on HVAC systems, consider the following strategies improve comfort and add convenience:

• Employ zoning strategies that give control over the thermostat to many.
• Specify raised floor systems with individual, adjustable air vents.
• Establish an easy way for occupants to request temperature or humidity changes to facility managers. In response to occupant requests, the maintenance staff may have overridden building control settings in a way that was intended to be temporary. Check these settings regularly to ensure that comfort and energy are both preserved.
• Set up electronic alerts as to when opening windows is recommended. Establish a “floor walk” routine to make sure that operable windows are closed during unfavorable conditions.

Providing high quality thermal and ventilation comfort as part of Indoor Environmental Quality (IEQ) in commercial offices is a high priority for federal projects. Happier and more comfortable occupants tend to miss fewer days of work and perform at sustained levels when achieving tasks throughout the day. Good HVAC design tends to prevent extreme hot or cold conditions, keeping the majority of occupants comfortable. For those people who “run hot” or “run cold,” controllability of temperature and air flow can have tremendous benefits to health and productivity. Systems with smaller zone control can accommodate the occasional after-hours worker, conditioning a small portion of the space rather than heating or cooling the whole building. Increased filtration of indoor air can reduce allergy attacks. Proper ventilation can also keep workers alert, while removing stale air and unpleasant smells.