Energy saving claims for lighting controls in commercial buildings

Lighting systems consume a significant proportion of the energy used in commercial buildings, and the control of lighting use is an important determinant of the energy performance of buildings. A review and meta-analysis of lighting energy studies in commercial premises is undertaken to investigate difficulties with reported energy-saving claims for popular lighting control methods. Earlier studies have indicated that in some installations automated controls may save very little energy if they are replacing manual control. However, even where manual control would be a reasonable expectation, such as in private offices, it has been common practice to report saving in energy compared to the lights being used throughout the working day, which leads to overstatement of the energy-saving potential. However, generally, user behaviour cannot be reliably predicted, which makes it difficult to quantify properly the benefits of adding automatic controls. It is argued that savings should instead be quantified with reference to published norms for lighting use in commercial buildings.