I am installing my AVALON ASTORIA, which heats 2800 sq. feet pellet stove to outside wall with a straight installation & have an outside air kit. My book says the typical distance from a window that "opens" is 4 feet if you do NOT have an outside air kit. I called my retail store and they said it's only 18 inches from a window if you do have an outside air kit. However, i don't see this exception in my installation book.. I believe the retailer but I need to prove it to the building inspector after the installation...Anyone have this experience?