Approximately 40% of the total U.S. office floor space of 1.5 billion sq.m (16 billion sq.ft.) isleased space occupied by tenants. Tenant fit-out presents a key opportunity to incorporate energyefficiency within the real estate business cycle. We designed a package of energy efficiency measurestailored to the scope of a tenant fit-out. This tenant fit-out package (TFP) includes advanced lightingand heating, ventilating and air-conditioning (HVAC) controls as core measures, with ceiling fans,automated shading, and plug load controls as additional optional measures. We conducted laboratorytesting of six configurations of the package to evaluate energy savings, indoor environmental quality,and identify installation, commissioning, and operational issues. Combined savings for HVAC,lighting, and plug loads ranged from 33–40%. Lighting savings ranged from 69–83%, and HVACsavings from 20–40%. The laboratory testing also revealed some minor but tractable challenges withinstallation and commissioning of HVAC controls. Overall, the results demonstrate that significantsavings can be realized in existing office buildings by incorporating relatively low-risk, provenmeasures at the time of a tenant fit-out.