GBA prepared an ASHRAE Level 3 energy audit, including a calibrated energy model, and devised ways to reduce pressurization to improve conditions in the lobby and skyway connections. In addition, many recommended energy conservation measures and some capital improvements were implemented.
- CONTAM modeling indicated that physical barriers to air infiltration would be more effective than HVAC-based countermeasures. New doors were installed on the skyway linking 801 Grand to other buildings, and high-speed doors were added to the parking levels.
- A Level 3 energy audit, done as a collaborative project between JLL and GBA, resulted in recommendation of energy conservation measures. Current-sensing data loggers were employed to collect data; GBA and JLL also did off-hours walk-throughs to help assess conditions when occupancy was low.
- Eleven low- or no-cost measures were implemented, totaling $224,515 in annual savings, with a payback of less than a year. In addition, seven capital improvement measures with a longer payback were implemented, in line with the client’s goals for a deep energy retrofit. Total bundled implementation costs were about $3.05 million, with verified annual savings of $424,175 and a combined simple payback of 7.2 years.
- Among the low- and no-cost measures with the best savings were seasonal adjustment of HVAC schedules ($178,470/year savings, no cost) and turning off bathroom exhaust when the building is unoccupied ($9,560/year savings, no cost).
- Lighting and controls retrofits on tenant floors also provided cost savings for the occupying firms.
- The project received an Excellence in Engineering Award from the Illinois Chapter of ASHRAE, a First Place Technology Award from ASHRAE Region VI, and an ASHRAE Society-level First Place Technology Award.