Are Energy Savings Due To Ceiling Fans Just Hot Air?
Sonne, Jeffrey; Vieira, Robin; Parker, Danny; Anello, Michael
Human comfort studies have shown that people prefer higher temperatures when they are subjected to a breeze. Ceiling fans are often used to create air motion in residences. Simulation studies (including one given in this paper) have demonstrated that in Florida, using ceiling fans combined with raising a home's temperature 2° F will generate about a 14% net savings in annual cooling energy use (subtracting out the ceiling fan energy and accounting for internally released heat). This savings drops to 2.6% with a 1° F increase in set point and to a negative 3.7% savings with only a 0.5° F increase in set point. If the thermostat is not adjusted at all for fan use, cooling energy use may increase by 15%. The sensitivity of the simulation to changes in the convective heat transfer coefficient between indoor air and indoor surfaces from ceiling fan operation is also presented. The sensitivity is inconsequential for insulated houses. This paper also presents metered results from an analysis of 400 Florida households that indicate no cooling energy savings due to ceiling fans. Homeowner-reported thermostat settings were the same for homeowners with and without ceiling fans and measured thermostat settings were not statistically different for a sample of homes in which the indoor air temperature was measured.
Buildings - Cooling
Florida Solar Energy Center and James, Patrick, "Are Energy Savings Due To Ceiling Fans Just Hot Air?" (1996). FSEC Energy Research Center®. 768.