Most outdoor propane patio heaters come with assembly instructions, so it's important to read these carefully before installing the patio heater. Outdoor propane patio heaters typically require a 20 pound or larger propane tank, which must be installed by a professional if it isn't already present on your property. If you do not have access to an outdoor propane grill, many manufacturers offer optional alternatives such as natural gas conversion kits. In addition, make sure to place the patio heater in a well-ventilated area and keep it at least five feet away from any combustible materials.