The enjoyment of a meal can be lost if you are concentrating more on keeping warm than on your food. These conditions can affect the happiness of the diner, and whether he or she will return to the restaurant. This way the entire room is heated and cooled and the diner can eat in a comfortable and relaxed state. This way the diners are comfortable, as are the workers of the restaurant. You have to go through one set and then through another set to actually enter or exit the restaurant.
Restaurants have two reasons for the double doors.
The first is that the air exchange from the outside to inside can be greatly reduced. This helps to keep a nice comfortable temperature in the restaurant for the diner. A second reason is that this in turn helps to keep down utility bills for the owner. Lights should always be placed to reduce glare, tilted and directed in such a way that it does not blind. Dining lights should be placed directly above tables, emphasizing the table displays and not the aisles.