Firms using up to 10% of UK power to cool buildings – even when nobody’s there


London_SunsetA new report by BRE suggests that as much as 10% of UK power generation is being used to cool non-domestic buildings – even at the evening and weekends when staff have gone home.

The two-year study on air conditioning use was commissioned by the Department of Energy and Climate Change (Decc) – now part of the Department of Business, Energy and Industrial Strategy. It delivers some interesting insights into how energy is being used and the factors influencing consumption.

The aim of the study was to improve Decc’s understanding of UK electricity usage by air-conditioning (AC) in UK non-domestic buildings. Led by Dr Andy Lewry, BRE’s principal consultant in the sustainable energy team, the study included 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; and developing procedures to extend the scope of Decc’s product policy model.

The main findings and outcomes of the research and report 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 increased from 5 in 1961 to 17 in 2003.
  • The proportion of buildings with air-conditioning is increasing. The study estimates that 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 over half of 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, which tend to be generic with the focus on improving controls and maintenance.
  • Recommendations for updating the key inputs into Decc’s existing product policy model of air conditioning electricity demand and development of an algorithm to estimate peak and monthly demand to supplement it.

BRE has also put together a dissemination plan aimed specifically at air-conditioning designers and technicians, building managers and smart system designers

The full report with appendices is available here as a free download.

Relates stories:

European Commission steps up focus on energy efficient heating and cooling

Supermarkets and data centres afraid to challenge energy load assumptions

Click here to see if you qualify for a free subscription to the print magazine, or to renew.

Follow us at @EnergystMedia. For regular bulletins, sign up for the free newsletter.


  1. The Gov needs to get behind ACIs – on ESOS and Heat Networks too – and do something similar to Scotland with their Section 63. Enforcement would create jobs, lower energy demand, reduce the need for Hinkley and generally be the ‘right thing’,

    CHP and DHCHP or CCHP may well follow – that can be left to market forces – but this is about firms simply wasting energy, not where they should get it from.

    Without enforcement we will struggle to get anything done before peoples personal worlds start to fall apart (e.g. floods and storms). That will be even more costly in more ways than one – if business thinks legislation is expensive they should look at all the reports pricing up the cost of inaction in lives and conflict as well as simply money terms. That is what hard-headed business is about, not the short-term soft option of inaction.


Please enter your comment!
Please enter your name here