We, at Arcola Theatre were thinking about getting an “air curtain†for our front door. An “air curtain†is when you have hot air blowing from above the door frame, to maintain the temperature inside although the door to the outside is open. Now we decided to close the door instead, after reading that this would cut 10 tonnes of our annual CO2 emissions. For more information about this research, look up “Close the Door†Campaign.