Cambridge University research proves closing a shop door in winter saves up to 50% in energy usage and carbon emissions

New research proves exactly how much energy is wasted by shops leaving their doors open with the heating on.

The research found that closing a shop door when heating is being used:

• Reduces energy usage by up to 50%
• Cuts a shop’s annual CO₂ emissions by up to 10 tonnes of CO₂, equivalent to 3 return London Hong Kong flights ⁽¹⁾
• Assists with mandatory national 34% reduction in carbon emissions 
• Enhances comfort of staff and customers, maintaining temperature at Chartered Institution of Building Services Engineers (CIBSE) recommended levels all day, even when outside temperature plummets
• Maintains energy use at a standard low level
• Enables heating to be shut off long before the end of the day without affecting internal temperatures
• Stops need for so-called “air curtains” over the door – among the greatest wasters of energy: a single one consumes 24 kWh per day. This is equivalent to emitting 91 kg CO₂ per week, or more emissions than a return Glasgow London coach trip

The research found no conclusive evidence that footfall or transactions were affected by closing the shop door.⁽²⁾

About the study

• Conducted over the winter of 2009/10 in Cambridge
• Research by the Glass and Façade Technology Group, Department of Engineering, University of Cambridge
• Commissioned by the Close the Door Campaign who were funded by The Esmee Fairburn Foundation. 

For the original research see the summary presentation and report. Please contact the campaign with any questions on  This e-mail address is being protected from spam bots, you need JavaScript enabled to view it .

(1) Based on an average of 150 days a year being cold enough for shops to need heating in Cambridge

(2) The study approximated footfall by measuring door openings when the door was closed, which is an underestimate as groups are counted as one door opening, and no consistent trend was found when compared with beam-interruption footfall data for open doors. To accurately compare transactions would require a larger sample and/or would need to take into account effects specific to the days measured e.g. day of week, weather, public events or offers in competitive shops.