Camper water heater

[Dorthbison]

I'm thinking about installing a tankless portable water heater, instant camper propane water heater in my small truck camper. I see folks cautioning about the effects of a propane flame in an enclosed space. But these heaters are not producing a flame anywhere near as long as a propane cooking stove, yet no one cautions about cooking a stew for hours on the stove.....What say the forum?