In light of the recent launch of the Minimum Energy Efficiency Standard and its expected impact on the commercial buildings sector, this study investigated the impact of adding cooling systems on the annual energy consumption, carbon dioxide emissions and energy performance certificate (EPC) rating of an existing UK hotel. Thermal Analysis Software (TAS) was used to conduct the study, and the baseline model was validated against the actual data. As is the current accepted procedure in EPC generating in the UK, the cooling set points of the guest rooms were set to 25 °C, resulting in a small increase in the annual energy consumption and emission rates, but not enough to change the energy performance certificate rating. Also, it was found that an improvement in energy consumption and energy performance certificate rating of the hotel would be achieved if the new systems replaced the existing heating systems in the guest rooms. Further simulations investigated more realistic situations, in which occupants may decide to keep their rooms at cooler temperatures. The results from this round of simulations showed considerable increase in the energy consumption and emissions of the building; however, these results would not be considered in the current approved procedure for EPC generating.