Controlling your thermostat is one the best ways to save energy within your facility. By adjusting and maintaining your thermostat and installing a few simple controls, you can save energy with your current heating, ventilation and air conditioning system.
Begin by adjusting your thermostat to a temperature no lower than 78° for cooling and no higher than 68° for heating. Contrary to popular opinion, it never costs as much to "heat up" or "cool down" a building to the desired temperature over a period of time. Turning down your thermostat just 3° in the winter, for instance, will save approximately 9% on your fuel bill; a 7° reduction will save approximately 20%. however, when operating an electric heat pump it is recommended that a constant temperature be maintained during the winter unless demand control equipment is present. Check local codes (when necessary) to determine what temperatures must be maintained. Once you've made the adjustments, install a clear plastic or opaque lockable cover so that only authorized persons have access to the thermostat.
Dead Band Capability
The dead band control consists of a 5° - 10° "band" on the thermostat. It eliminates the possibility of simultaneous heating and cooling. When temperatures fall within the 5° - 10° zone on the band, say 68° - 73°, neither heating nor cooling can occur. A dead band might compromise comfort, and may be unacceptable in situations where there are elderly persons or invalids.
Solid-state thermostats are especially effective to discourage tampering, since the only way to change the temperature setting is to replace the small glass sensor inside the thermostat. To protect against tampering even further, it is advised that only one person have access to the replacement sensors and locking covers be installed.
A duct limiter fits inside the return air duct, hidden from view. Select the cooling or heating setting on the duct limiter and connect it to the room thermostat. When the thermostat is turned on, the duct limiter will cool or heat to the temperature selected. Room occupants may tamper with the thermostat without affecting temperature settings. The room thermostat can, however, be used to turn the system off when the room is unoccupied, or on when the room is in use.
Some duct limiters are designed to control either heating or cooling; others can control both modes. Solid-state duct limiters are also available for even greater protection of settings.
Thermostats should be checked and calibrated periodically, along with heating plant annual maintenance. This is especially important in buildings which house dusty equipment or materials and low voltage controls where extra care is needed to maintain clean, efficient electrical contacts.
Setback thermostats, also called occupied/unoccupied controls, automatically lower (or increase in summer) temperatures when the building is unoccupied, thereby reducing heating or cooling needs. A 24-hour programmable thermostat can be programmed to automatically change thermostat settings ("setpoints") two or more times a day. A seven day programmable thermostat can be customized for different days of the week.
With a stand-alone time clock, the temperature can be adjusted by using the clock with dual-temperature setpoints over periods of 24 hours of seven days - or even a full year, allowing automatic adjustment during holidays. Some time clocks allow control of temperature, lighting and ventilation systems.
Optimal Start Capability
An optimal start capability may accompany the installation of an occupied/unoccupied control system. This allows for varying start-up time in the morning depending on outside temperatures. Cooler exterior temperatures will require a longer warm-up time.