When selecting the mounting location, it all comes down to your room layout, air circulation, furniture placement and how those things work in conjunction with heater clearance requirements and guidelines.
Here’s a quick rundown of the best practices and things to avoid:
Fan heaters work best on an inside wall; baseboard are best under a window. (But you can install fan heaters on outside walls and baseboards on inside walls.)
If you’re installing a heater by a door, make sure the heater isn’t blocked by the door when it is open.
You cannot have an electrical outlet above or below the heater.
Baseboards and fan heaters cannot be blocked by furniture, bedding, drapes or anything else.
Allow 3 feet of clearance in front of a fan heater; 6 inches to the sides and 12 inches above the heater.
Allow 12 inches of clearance in front of a baseboard, 6 inches to the sides and 12 inches above the heater.