© 2017 The study investigates uncertainty of financial performance of energy efficient office buildings to establish how making an asset energy efficient changes its financial characteristics. Two hypotheses explaining why a change may occur are presented and examined (one based on higher demand and one on higher economic efficiency). A large panel dataset, consisting of 30 time periods for 14,395 US commercial office buildings, is examined using different econometric approaches. Overall, the results seem to support theoretical predictions and show a structural change in energy efficient assets. Rental levels appear to be systematically different in buildings which hold energy certification. The average effect, over the investigated period, was a small premium although significant variations are found between different years.