This paper focuses on the effect of energy performance ratings on appraised capital values, rental values and equivalent yields of UK commercial property assets. The study is based on a cross-section of 708 commercial property assets. Incorporating a range of potential confounding factors such as unexpired lease term, vacancy rate and tenant credit risk, we use hedonic regression procedures to estimate the effect of EPC rating on rental and capital values. The study finds no evidence of a significant relationship between environmental and/or energy performance and rental and capital values. A small subset of 24 BREEAM-rated assets is also tested for significant price effects but a statistically significant effect is only confirmed for equivalent yields. Similarly, there was no evidence that the EPC rating had any effect on Market Rent or Market Value with only minor effects of EPC ratings on equivalent yields. The preliminary conclusion is that energy labelling is not yet having the effects on Market Values and Market Rents that would be expected if high EPC ratings were associated with substantial cost savings that are fully reflected in capital values and/or were readily available and taken into account by prospective tenants and buyers. (C) 2011 Elsevier Ltd. All rights reserved.