Indoor comfort is largely a matter of individual preference, so there is no specific thermostat setting that can be considered the “best.” The cost associated with lowering or raising the indoor temperature is dependent on a number of factors including local weather conditions, the SEER rating of the unit, and the quality of the building’s construction.
As a general rule, raising the thermostat one degree will save up to five percent on monthly air conditioning costs. While Natural Resources Canada recommends that the indoor temperature in the summer should be set as high as possible while still maintaining indoor comfort, homeowners are encouraged to raise the thermostat at least five degrees when leaving their home for over four hours.
The following chart can serve as a guideline for energy saving thermostat settings throughout the day:
Morning: 78 degrees Fahrenheit
Leave Home: 85 degrees Fahrenheit
Return Home: 78 degrees Fahrenheit
Before Sleeping: 82 degrees Fahrenheit
Many people believe the common misconception that less energy is consumed when a building is kept at a constant temperature. In fact, the rate of energy consumption is substantially lower when the indoor temperature is kept closer to the outdoor ambient temperature. Numerous studies have verified that the cost of climatizing the building upon reentry is far less than the total cost of maintaining a lower temperature when your home is unoccupied.
There are two primary choices in thermostat operation, including manual and programmable varieties. Homeowners interested in simplicity and a low purchase price usually choose a manual thermostat. A programmable thermostat offers a variety of features that are designed to reduce air conditioning utility costs and enhance overall comfort.
In areas with high humidity, it is important to verify that the capacity of your air conditioning system is accurately matched to the total load. Unfortunately, equipment that is oversized will short cycle, which can degrade humidity control, especially when the temperature setting is raised.
Inexpensive improvements to the building itself can also help improve comfort and lower utility bills. Specifically, raising insulation levels, sealing the perimeter envelope and sealing the interior ductwork will all help create a more efficient indoor environment.