Wasted heat

Something that irritates me quite a lot during the winter, and particularly in the run-up (the what? - is it an athletic event?) to Christmas, is the habit of shops leaving their doors wide open in freezing weather. This is no doubt to make customers feel welcome and remove any barrier to them entering and spending lots of money. It is shockingly wasteful of heat though. I wonder if it's budgetted for separately. And I've never noticed anybody anywhere pointing this out before.