Mr. Heater Big Buddy Indoor/Outdoor Propane Heater

I have one, but I've never used it in my pop up. I usually camp at a spot with an electric hookup and just use a ceramic heater which works nicely to heat the popup. I wouldn't hesitate to use the Mr. Heater Buddy heater in my popup when awake. Like others have said, I'd be hesitant to use it when sleeping. Anything with an open flame that puts out carbon monoxide (minuscule amounts but still) and burns oxygen is probably best used when you are fully awake.