I couldn't imagine rving without our Mr. Heater. I read the reviews, the warnings and the Mr. Heater advice. They've been in business since 1955 so they have somewhat of a track record.
We used ours last summer in April/May on our northwest U.S./Canada trip where we stayed at elevations up to 8000 ft and temps as low as -5C. This winter in the mountain snows in Durango, Mexico at -9C. The Mr. Heater worked beautifully.
A little education and common sense goes a long way. We cracked a kitchen window (front of rv), a living room window (middle of rv) and the roof vent in the bedroom. We tested the CO2 alarm and LP gas alarm everyday, used the low heat setting. Our LP has a connection inside the rv so the shortest hose possible is used. The slightest movement to the heater and it shuts down. As LP tank empties the low pressure shuts down the heater (no low flame burning).
From the Mr. Heater FAQ:
WHY CAN THE BUDDY HEATERS BE USED INDOORS SAFELY?
There are a couple of required safety features needed for ventfree heaters to be used indoors safely. A BURNER that is 99.9% efficient at burning all the gas it consumes so that very little CO or carbon monoxide is emitted. The heater also requires a ODS or Oxygen Depletion System that will shut off the heater if the Oxygen level drops to a still safe 18%. Because these heaters are portable, they also require a TIP SWITCH so if they are knocked over the gas flow stops shutting off the flame and gas. Last there is a FLAME SENSOR safety shut-off system that will shut off all gas flow if the flame goes out.
Nothing in life is 100%. Use any appliance with caution. If I had a near-death experience in a car crash or a plane crash would I stop driving or flying?
Safe, inexpensive to purchase, uses much less LP, environmentally friendly. Rv furnaces exhaust so much heat to the outside they are wasteful and inefficient.