The American Express project was a new two-story, 145,000 sq. ft. office building. The HVAC system consisted of large roof-mounted HVAC units supplying air to VAV boxes with hot water reheat coils. Perimeter and interior temperature control zones were developed, using the VAV boxes to satisfy the heat loss and gain from a large amount of perimeter glass. Fan-powered VAV boxes using temperature and CO2 control were installed to serve conference rooms, ensuring fresh air ventilation. Tweet/Garot also provided the commissioning for the HVAC system.