801 grand

Energy modeling, facility assessment, troubleshooting, and combined low/no cost and capital improvements provided award-winning benefits for this Des Moines skyscraper.

Exterior of 801 Grand, Des Moines, Iowa

The Objective

801 Grand is a 44-story office building constructed in 1989 in Des Moines, IA. Podium levels include retail shops and restaurants, as well as a lobby and parking. The building is all electric, other than natural gas for cooking and for retail tenants in the podium level.

Owner and primary tenant Principal Financial Group and management firm JLL hired GBA to assist with LEED EB: O&M certification and to improve indoor environmental quality pertaining to air infiltration during cold weather. Principal desired building improvements in preparation for consolidating its own office space elsewhere in Des Moines, opening more space in 801 Grand for tenant rentals. In addition to saving money and demonstrating sustainability through LEED EB: O&M certification, Principal and JLL wanted to improve conditions for occupants by addressing air infiltration and pressurization issues. 

The Response

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.


Physical barriers recommended to solve pressurization problems

Data loggers and off-hours walk throughs employed to collect useful energy usage information

Low/no cost measures combined with capital improvement measures for maximum impact

ASHRAE awards at the state, regional, and international levels

The Results

Annual $ savings from low/no cost measures

Annual $ savings including capital measures

Payback (yr) including capital measures

801 Grand, Des Moines, Lobby Entrance