No, you cannot install your portable propane heater outside as it is not designed in such away. The reason behind this is that the strong winds can affect the flame of the heater and could extinguish it with its potential. You can use the other type of heater for an outdoor purpose such that the hot surface ignition heater or even the spark ignition heater. If there is no proper ventilation where your propane heater is being installed then it can prove to be a serious health cause for people working there in that room and may also lead to death.