It only takes a bit of common sense and a tiny minuscule amount of knowledge to know the answer to this question. Yet, there will be some people in the world who either completely ignore this or are actually too ignorant to know otherwise. To ensure you are not one of the latter people, this question is being addressed. Under no circumstance should you ever use a gas fire pit indoors. It has nothing to do with the heat, either; using a gas fire pit indoors has a risk of carbon monoxide poisoning. When you fire up a propane tank, it is going to release carbon monoxide and if you are exposed to it without proper ventilation it can lead to carbon monoxide poisoning. Carbon monoxide is odorless and colorless, and overexposure can lead to death. Seriously. Just be safe and only use it outside.