Air conditioning in non-domestic buildings

The report sheds important light on the electricity use of air conditioning in UK offices and retail environments. It presents the findings of a two-year study commissioned by the Department of Energy and Climate Change (DECC - now subsumed within the newly-formed Department of Business, Energy and Industrial Strategy) providing insights into how energy is being used and the factors influencing consumption.

The study, led by Dr Andy Lewry, BRE's principal consultant, involved:

Analysing existing cooling demand and consumption data.
Assessing air conditioning inspection reports and energy performance certificates.
Reviewing literature on trends in air conditioning usage and the possible future impacts of new technology.
Developing procedures to extend the scope of DECC’s product policy model.

The main findings include:

Cooling in air conditioning systems may account for around a tenth of total UK electricity consumption.
Heat-waves are becoming more frequent across the UK, and in the South-East of England the number of heat-wave days per year has increased from 5 in 1961 to 17 in 2003.
The proportion of buildings with air-conditioning is increasing. The study estimates that, in 2012, some 65% of UK office space and 30% of UK retail space was air-conditioned.
The study estimates that cooling in offices typically uses around 40 kWh/m2 per year.
Air conditioning is frequently used even when buildings are unoccupied, for example in the evenings and over the weekends.
The analysis of Energy Performance Certificates (EPCs) indicates that more than half of all air conditioning systems in the UK are split systems. Although only 10% of EPCs have AC recommendations; these mostly relate to more efficient equipment, including variable speed drives, and reducing air leakage from ductwork
An analysis of the recommendations in air conditioning inspection reports, reveals that they tend to be generic with the focus on improving controls and maintenance.
Recommendations for updating the key inputs into DECC's product policy model of air conditioning electricity demand, and the development of an algorithm to estimate peak and monthly demand to supplement it.