RV Repair Manual
for the RV Do-It-Yourselfer
A catalytic heater burns propane in an efficient manner (almost 100% according to some manufacturers) and uses little or no 12-volt power. It sounds great for RV use ... but is it?
Ideal propane combustion in a catalytic heater produces only heat, water vapor, and carbon dioxide. It also uses oxygen from the immediate environment and exhausts the products of combustion into that environment. Therefore, oxygen must be replaced and water vapor and other byproducts removed from the RV in some manner.
Catalytic heater manufacturers suggest leaving a window open or providing another source of fresh air. Hmmm ... what if a child gets up in the night and closes that window?
Less than ideal combustion produces carbon monoxide. Carbon monoxide is a killer gas – odorless, colorless, and invisible.
RV furnaces are designed with a sealed vent system – outside air is drawn into the combustion chamber to supply the flame with oxygen, and combustion byproducts are exhausted outside. Water vapor produced by the flame is also vented outside. While RV furnaces use more fuel and electrical power, they operate safely.
Many people swear by their "cat" heater, while many others warn of the associated dangers.
A new type of vented catalytic heater is presented by the website listed below (provided for informational purposes only; not an endorsement):
"THE PLATINUM CAT utilizes a power vent system which exhausts all combustion by-products to the outside of the living area, which automatically replaces oxygen used for combustion. The vent system prevents buildup of unhealthy indoor air pollution and eliminates any chance of accidental asphyxiation."
– Platinum Cat Vented Heater
I must replace the heat source in my 30ft fifth-wheel. I have heard low-pressure LP gas catalytic heaters are much more efficient than forced-air furnaces and don't require a battery. Most advertisements say their model is designed for RVs, but the last sentence says they do not meet ANSI A119.2 standards for RVs. Are they safe, and how much ventilation do they need? Any advice would be greatly appreciated.
Some folks use 'em, some don't.
Les is adamantly against the use of catalytic heaters in RVs and, in fact, in some places in Canada they are illegal. The bottom line is that when using any fuel-burning device in an RV, sufficient ventilation must be provided to replace oxygen used and allow for the release of deadly gaseous byproducts.
Personally, I find it distasteful when a company recommends their catalytic heater for an RV and then adds the ANSI disclaimer to protect themselves if someone dies as a result of using one.
Well said, Mike. Any combustion process has to be vented outside or it will build up CO levels in the RV. I'd never use this type of heat as the only source in an RV.
Thanks Mike & Ken, I appreciate your input. I dry camp at wildlife management areas and was concerned about battery life with a forced-air furnace.
What about heating the RV in winter when nobody is occupying it? My 36' motorhome is right next to my house and I like to keep it above 40°F when not in use. I use a ceramic heater now, but at full throttle it draws 13 amps and drives up the electric bill.
I have read that catalytic heaters induce a heat-producing catalytic reaction rather than open burning, but they still consume oxygen. The Olympian brand has models with an Oxygen Depletion Sensor (ODS) that shuts the heater down if room oxygen gets too depleted. Zero-electricity appliances make sense for dry camping, but safety is the big question.
Not long ago, two kids my daughter grew up with went hunting in winter. They used a catalytic heater in their tent and opened a window flap for air exchange. Sometime during the night, the flap became untied and closed. The boys never woke up.
Taking a chance just isn't worth it, especially when used for comfort rather than survival.
Just last week our local newspaper reported that two soldiers died in their tent one night while on maneuvers. The catalytic heater they used to heat their tent created the conditions that caused their deaths.
I remember using a small catalytic heater back in the '70s while camping in my friend's van. We used to wake up with terrible headaches even when we didn't drink. I'd stay away from anything catalytic.
Carbon monoxide (CO) is produced by incomplete combustion. CO attaches itself to blood hemoglobin, keeping the blood from absorbing and transporting oxygen throughout your body. Combined with oxygen depletion inside an enclosed space, an unvented heater creates a severe hazard.
Catalytic heaters are fine in well-ventilated areas with a continuous fresh-air supply, but sealing yourself in a small area with an unvented fuel heater is extremely dangerous.
I want to thank everyone for spending their time to respond. I think I'll go with the consensus and sidestep the dangers in favor of the normal factory furnace.