Smart Ceiling Fans and Communicating Thermostats to Provide Energy-Efficient Comfort
Research Team:
U.C Berkeley’s Center for the Built Environment (prime), TRC, AEA, Big Ass Fans
Smart Ceiling Fans and Communicating Thermostats to Provide Energy-Efficient Comfort
Research Team:
U.C Berkeley’s Center for the Built Environment (prime), TRC, AEA, Big Ass Fans
Challenge
The electric peak demand in California is driven by summer-time air conditioning loads in residential and commercial buildings. Air conditioning has become a necessity in many climate zones: extreme heat events kill more Americans every year than any other weather-related disaster (US Department of Homeland Security 2020), and as climate change progresses, heat waves are increasing in intensity and frequency (Center for Climate and Energy Solutions (C2ES) 2017). Low income populations are increasingly more vulnerable as these communities often lie in areas disproportionately warmer than wealthier communities (Anderson and McMinn 2019), their houses tend to be less efficient (Berelson 2014), and they pay more of their income for energy (Alamo, Uhler, and O’Malley 2015).
Project Objective
The project goal was to identify and test the integration of smart ceiling fans and communicating thermostats. These highly efficient ceiling fans use as much power as an LED light bulb and have onboard temperature and occupancy sensors for automatic operation based on space conditions. The Center for the Environment (CBE) at UC Berkeley led the research team including TRC, Association for Energy Affordability (AEA), and Big Ass Fans (BAF). The research team conducted laboratory tests, installed 99 ceiling fans and 12 thermostats in four affordable multifamily housing sites in California’s Central Valley, interviewed stakeholders to develop a case study, developed an online design tool and design guide, outlined codes and standards outreach, and published several papers. The project team raised indoor cooling temperature setpoints and used ceiling fans as the first stage of cooling; this sequencing of ceiling fans and air conditioning reduces energy consumption, especially during peak periods, while providing thermal comfort. The field demonstration resulted in 39% measured compressor energy savings during the April–October cooling season compared to baseline conditions, normalized for floor area. Weather-normalized energy use varied from a 36% increase to 71% savings, with median savings of 15%.This variability reflects the diversity in buildings, mechanical systems, prior operation settings, space types, and occupants’ schedules, preferences, and motivations. All commercial spaces with regular occupancy schedules (and two of the irregularly-occupied commercial spaces and one of the homes) showed energy savings on an absolute basis before normalizing for warmer intervention temperatures, and 10 of 13 sites showed energy savings on a weather-normalized basis. The ceiling fans provided cooling for one site for months during hot weather when the cooling equipment failed. Occupants reported high satisfaction with the ceiling fans and improved thermal comfort. This technology can apply to new and retrofit residential and commercial buildings.