[IYAS9YAS]

One thing I got 2 weeks ago is a Mr. Heater Portable Buddy 9000BTU propane heater. I LOVE that thing. Heats my basement up where I’m at my computer pretty good. I have the extension hose that allows you to connect it to a 20 lb propane tank. Got it on Amazon for $85 free shipping....

While they say they're rated for indoor use, they are full of disclaimers saying not to use it inside your actual living space (good for garages, tool sheds, etc...). You really should have some good ventilation for that unit.

[Gaffer]

In an open basement, it’s not a problem. There is enough outside air infiltration (I have an insulated boat door) and it has an oxygen sensor and I also have a carbon monoxide detector. I also do not leave it alone unattended.