PDP 200,000 BTU Propane Gas Vertical Power Vented Unit Heater

There is no definitive relationship between dimensions of floor space and how much heating capacity needs to be installed. As I am sure you can imagine the same structure if located in Alaska is going to need significantly more heat than if it were located in Florida. To know what you need for capacity you should do a heat loss calculation. There are plenty of free programs on line that do this. Myself I use the Slant Fin heat loss calculator. You can download it at the Apple or Droid app store. You enter the dimensions, building material, location, windows, etc.. and it will calculate how much heat, in BTU's the structure loses on the coldest hour of the coldest day of the statistical year. Thus you know how much heat you need to put back in to the structure to keep it at a constant temperature. Then you can search for a heater that has that output in BTU's. Under the header "Info and Guides" on the Home Depot product listing page, you will find a PDF of the care and use manual. If you open it you will find info on suspending the unit begins on page 4. The unit is manufactured with 3/8" threaded connections on the top. Typically hang them using 3/8" threaded rod that I screw into these receivers. I attach the other end to the ceiling using conventional pipe hanging hardware. I would think you could mount a bracket to the wall and have it come out and receive the rod.