Keeping the air in while welcoming customers can be difficult. This can be a problem in older buildings as well as new. Yesterday I noticed one solution at the National Innovation Centre, at the Australian Technology Park while at "Startup BarCamp Sydney". This building was part of the historic Eveleigh Railway Workshops. The building has large brick arched entrance, which could not be made airtight on the outside without detracting from the historic look of the building. Instead the a large glass wall has been built inside the entrance. From the outside the glass is not noticeable.
Apple could consider this approach building a glass box inside the doors of its store (which in itself is a large glass box). The inner wall created could have self closing or revolving doors.
While smaller historic buildings could not afford the space that ATP and Apple have, they could consider a similar approach by leaving the wood door open and using a modern glass one to close the entrance for air-conditioning, while retaining an open look for customers. There are detailed guides to making historic buildings energy efficient.