First of all, you need to check the specifications of the building that includes the length, width, height of the wall, type of animals, rate of ventilation, type of insulation, and also the thickness. With all these above specifications one can easily calculate the load of heat and also can determine the size and quantity of the portable propane heater you require. You also must know the NG or LP to identify the size of the gas piping required by your heater. Along with that, you must know the distance between the gas supply and your building and also between the heaters so that they become efficient in use. You can also make use of the sketch of your building, gas supply, and the layout of the heater so that it can prove to be the best decision for having an efficient barn with the perfect size of the installed heater and gas piping.