Table 1.

Building characteristics.

Type of building	Multi-storey office building
Dimension	17,402 m2 (8,585 m2 heated)
No. of Employee	~350 employees
Location	Frankfurt, Germany
Thermal characteristics	High energy standard of building envelope Walls: U-values 0.24 to 0.5 W/m2K) Windows: U-values 1.5 W/m2K, solar transmittance <40%, light transmittance 70%
Structural system	Reinforced concrete construction
Type of observed spaces	Office rooms
Year of construction	2002
No. of floors	2-level underground car park +4 office floors + 1 floor apartments on top
Window dimensions	Windows: Top lights
Windows, orientation	Mostly E and W
Window opening	All windows open inwards. No obstacles prevented window opening except those potentially added by occupants (e.g. plants or papers placed in front of window) Windows: Manual opening through window handle by occupants only, windows had hinges on one side and could be fully opened (rotated) to any degree up to 90° opening angle Top lights: automatic control + manual opening through switch next to office door by occupants, windows had hinges at the bottom and opened on top; any degree up to ° was possible at manual control; at automatic control for night-time ventilation the angle was predefined in order to balance pressure difference between floors and achieve almost the same volume flow for each floor and office.
Window control options	Automated 10 minutes flush ventilation before working hours through top lights in the façade and between office and corridor Afterwards: Top lights: Tilt (automatic + occupant driven mode), Windows: Tilt-and turn (occupant driven)
Shading devices	External sun protection (automatic + occupant driven mode) with different angle of blinds in the upper part to provide daylight guidance. Sun protection consists of light metal Venetian blinds with a slats width of 80 mm and a reflectance of 60%..
Predicted annual primary energy consumption	107 kWh/m²
Monitored annual primary energy consumption	100 kWh/m² in third year of monitoring