Here're some 'facts' gleaned from my own experience and from reading other RV groups:
1. The Buddy Heater is NOT catalytic; not to say it isn't safe, but it's not catalytic despite how Camping World continues to list it (Don't take my word for this, call Mr Heater and ask them) -- The ODS system used on many non-Cat vent-free heaters will shut the thing down long before O2 levels drop anywhere near dangerous levels. Also, last time I looked, not all Olympian heaters are catalytic.
2. The most tech-inclined guy I know is currently an over-the-road trucker (and RVer), sleeps in his cab bunk and heats it with a Coleman Black Cat -- He has rigorously tested it with an O2 meter and pronounces it safe, just as Coleman says, with the appropriate ventilation specified by Coleman.
3. Same guy uses a NiteHawk CO monitor because it also gives out the actual CO reading, esp when using LP rangetop.
4. Reportedly, the CO monitors for home and RV differ in the level at which they alarm; ostensibly so fire departments don't respond to false alarms -- Given that a home has more volume and the alarm threshold may be set higher, these factors may or may not offset each other (hence my friend's preference for a monitor that reports actual levels) when used in RV.
5. RV furnaces of age and rough use, the heat exchange kind, have been known to leak between the combustion and clean air chambers, plus there is always a possibility of exhaust air leaking back into the RV with prevailing wind conditions and air leakage of door and window seals.
6. Having a way to shut off the CO monitor is a good thing, esp if you have a generator
, because the generator
or a nearby idling automotive engine will indeed produce alarmingly high CO levels (Pun intended