Empire GWT50 White Gravity Vented Wall Furnace

You've accurately identified a point of potential confusion. According to the Empire installation manual, the GWT50 is designed for installation within a standard 2x4 stud wall cavity with studs spaced 16 inches on center. The unit itself is 16 inches wide. While the manual specifies minimum clearances of 4 inches on the sides, 12 inches at the top, and 1 1/2 inches at the bottom, it doesn't explicitly detail how the 4-inch side clearance is achieved within the 16-inch stud bay. After confirming with the manufacturer, the 4-inch clearance requirement pertains to the portion of the furnace that protrudes from the wall. This means the unit should be at least 4 inches away from any door or window trim, and similarly, furniture should be positioned at least 4 inches from the sides of the furnace if it's placed against a wall. The section of the furnace installed within the stud bay does not need to meet this 4-inch clearance requirement.