Special Maintenance Considerations - Effective Building Maintenance: Protection of Capital Assets - page 86

this, the facility maintenance staff can typically implement improvements
in three areas:

HVACOperatingSetpointsandSchedules
Establishing on-off (occupied-unoccupied) schedules with indi-
vidual temperature setpoints can reduce energy consumption by heating,
ventilating, and air-conditioning (HVAC) equipment by 10-25%.
In larger facilities that have a facility-wide direct digital control sys-
tem, this system should be used to schedule operation of every piece of
HVAC equipment and establish temperature (and, as required, humidity)
setpoints for each occupancy period. But, even in simple facilities (branch
banks, dentist offices, retail stores, etc.), replacing older existing thermo-
stats with newer programmable, seven-day thermostats (a $40-$150 in-
vestment) is very cost effective.
In order to have good indoor air quality, temperature setpoints
should in the range of 72-77°F (cooler in winter and warmer in summer).
Thermostats that have automatic changeover for heating to cooling and
vice versa, should have at least a 5°F “deadband” or difference between
the heating and cooling setpoint temperatures. And, thermostat setpoints
should not be adjustable by the facility occupants. Setpoints should be
changed by the maintenance staff, only, in accordance with facility policy.
This eliminates occupants adjusting thermostat setting too low or too high
and wasting energy and resolves most of the “too hot/too cold” conflicts
that can arise. Finally, purchase thermostats that have no temperature dis-
play; often people decide they are hot or cold based a thermometer read-
ing.
Humidity control, particularly in facilities located in hot, humid cli-
mates is necessary to prevent the development of mold infestation. Modi-
fying existing systems to incorporate humidity control, adding humidity
sensors or humidistats, and establishing humidity setpoints may be re-
quired. To minimize the energy expended for humidity control, humidity
setpoints should be in the range of 30% RH (winter low limit) to 60% RH
(summer high limit).
In addition to space temperature and humidity setpoints, there are
other setpoints in HVAC systems that are critical to energy consumption:

• For constant or variable air volume air handling systems that pro-

vide supply air at a constant temperature, that temperature setpoint
should be as high as possible while maintaining comfort conditions