The Impact of Operable Windows on a High Performance Office Building in U.S. Midwest

This case study evaluates how the operable windows improve energy efficiency and indoor air quality for a state government office building. The IUB-OCA building is certified as Energy Star 100 and LEED Platinum. The measured energy use intensity is 21.5 kBtu/ft²-yr. One of low-energy sustainable design features is the operable window. The building automation system identifies favorable outside conditions and notifies occupants to open or close windows. The associated zone’s heat pumps are automatically shut down when windows are opened. The study analyses the impact of the operable windows on heat pump energy savings and occupant satisfaction through natural ventilation.