Winter’s frigid freight train blasted into the U.S. early this year, causing more RVers to think seriously about heading south to escape the cold. Don’t let anybody fool you, the Desert Southwest may be shirtsleeve weather by day, but winter nights can be down right chilling.
If you plan on staying on that low-cost desert land, how can you warm up without wiping out your battery bank? There are some attractive and relative easy alternatives. First, consider that the typical RV furnace chews up both propane and electricity. RV furnace design is taken from land-based forced air systems, which heat up the air in an enclosed firebox, circulating cool air over the outside of the firebox, and blasting it out through the rig with a fan.
Put your hand near the outside exhaust port and you’ll find plenty of heat blasting out—enough to burn your hand. Tons of British Thermal Units rush out of your firebox, only to contribute to desert warming. A forced air RV furnace isn’t all that efficient on LP. But for the boondocker, the real problem is how much electrical power the furnace consumes.
Even a small, non-ducted furnace system (like those used in truck campers or pop-ups) can chew up five amps of power for every hour of operation. The bigger your rig, the more ducting the air has to be pushed through, and in short order, you can eat up your battery banks overnight. Really, a forced air RV furnace is best used when tied up to shore power, or for short spells to take the chill off. What’s your alternative to freezing?
While our own four-footed feline thinks our “cat heater” was made just for her, “cat’ stands for catalytic. These flameless heaters are the “cat’s meow” for producing lots of heat with little or no electrical power consumption. They use a specially coated catalyst “bed” or mat to efficiently burn propane. They are flameless after lighting—they do produce a bit of a flare when first being started—as our own cat was rue to find out. She stuck her face right up to the heater and it flared, giving her a close shave, and the loss of a few whiskers. She learned quickly and now stays back several inches anytime we’re lighting the thing up.
Catalytic heaters are highly efficient; 95 percent or better of your propane fuel is turned into heat, all of it released inside the rig. Most are small, and can mount directly on a wall, as they have very small clearance areas required. They can also be put on legs (cat feet?) and pointed wherever heat is needed. Since they are radiant heaters, they will quickly warm up any object or person in front of them, but they do take time to heat up the house. This is because the radiant heat of a cat heater has to be absorbed by something (or someone) and then gradually released. Think in terms of walls and floors. However, they are practical for heating your rig.
Catalytic heaters do have their drawbacks: Since they are non-vented, meaning that they don’t release anything to the outside of the rig, they will add moisture to your RV air. If you’re in an area of high humidity, a cat heater will add to the dampness. They also draw their air for combustion from inside your rig. The catalytic process requires less oxygen than an open flame, but it is a consideration. It is best to crack a window whenever you run a cat heater, so that the air that is used can be replaced.
The heart and soul of a catalytic heater is its catalytic “bed’ or mat. This specially impregnated material is where all the heating takes place. The bed is susceptible to pollutants, so if you frequent areas where air pollution is rampant, the bed won’t last as long as it might otherwise. Contaminants from propane or propane containers can also migrate their way up the propane lines into the catalytic heater, contaminating the bed. Our own catalytic heater has had to be sent in for service when gunk from the propane lines clogged some fine orifices, reducing the heat output significantly.
What’s to be done? Olympian, the maker of a large number of catalytic heaters, makes several recommendations. When not in use, catalytic heaters should be kept covered. You can buy specially designed covers from your catalytic heater manufacturer. This tends to keep the airborne pollutants off the cat bed. As far as fuel-borne contaminants, avoid using LP produced in Mexico. The company says this fuel often contains contaminants that can clog orifices and damage catalytic beds.
Olympian suggests propane cylinders be “purged” once a year to remove tank contaminants. This is an operation best performed by an LP dealer. It’s not an expensive operation, and with catalytic beds costing in excess of $100 (not to mention labor charges), it’s cheap insurance.
Cat heaters are rated based on their heat output, measured in BTUs (there they are again, those British Thermal Units!). The greater the BTU output, the higher the cost, but of course, the larger the area that can be heated.
Most cat heaters use NO electricity. This is great for solar and wind power users—stay warm while keeping the batteries for other uses. However, these no-power cats have a drawback: They have no thermostat. Generally, you’ll have a choice of high, medium, or low output, but if they’re on, they’re always heating. There are thermostat-equipped cat heaters that do use a small amount of power to control heat output to keep things more comfortable if the inside temperature fluctuates. Still, we’ve learned how to put up with the lack of thermostatic control and can usually tell at bedtime at just what setting to leave our cat heater.
Freestanding Flame Heaters
Other non-vented heaters actually produce a flame in operation. The flame is usually shielded behind safety glass, but still visible to the user. It’s almost like having your own fireplace (assuming you have a fair amount of imagination). Marketed under brand names like BlueFlame, these heaters generally have a higher heat output than a cat heater.
These flame-type heaters have a standing pilot light that allows the use of a mechanical thermostat. Nice, not having to use power, but still having a steady heat source. Some users leave their flame heaters on all the time, just set to the desired temperature. Others only fire them up when things get chilly, saving that small amount of propane by not leaving the pilot lit.
Being non-vented, this style of heater “breathes” your inside air. CAREFULLY follow the instructions of the manufacturer about how much you’ll need to leave a window open to make sure you wake up the next morning.
Not as “cute” as a flame heater, but costing less than a catalytic heater is the so-called brick heater. These heaters use a ceramic “brick” with tiny orifices as a heat source. Some have adjustable thermostats for “perfect control,” while others (cheaper) allow you to set the heat output, and live with it until you readjust it.
Like cats and flame heaters, they too, draw inside air for combustion. The same safety precautions apply.
Generally speaking, all of these heaters (with the exception of most catalytic heaters) have an ODS (Oxygen Depletion Sensor) that detects a low oxygen condition, and will shut themselves down before the oxygen level is so low that it could be harmful to air breathers like us. That can be a drawback if you take your rig to higher altitudes—the air being so thin at some levels that the heater won’t work. Be sure to ask your dealer about how high you can travel and still use your heater. A general thought is that when you are more than 4,500 feet above sea level, you may play Cain trying to get heat out of an ODS-equipped heater. Now’s the time to fire up that big gas-sucking forced air furnace. NEVER try to defeat the ODS system!
Since cats, flame type, and brick heaters all require propane to fire, you have to get the propane into them some way. Here’s another disclaimer: Be sure to follow all local, state, and federal applicable laws and codes when installing auxiliary heat systems in your RV. Check with your heater dealer about facts on these matters.
Some folks use copper tubing to tie into the RV propane system, leaving the heater right where it’s mounted. Others find that using the appropriate rubber tubing allows them to “point” their heater or move it where needed. Some even use “quick connect” fittings to allow them to disconnect the heater and move it to another place in the RV. If you decide to go with a “quick disconnect” fitting, USE ONLY THOSE SPECIFICALLY DESIGNED FOR USE WITH LP GAS. We know one RVer who swears he’s gotten away with using the cheaper, “made for air pressure” quick disconnects, but it could easily just be a matter of time before something could go wrong with fatal consequences.
Russ and Tiña De Maris are authors of RV Boondocking Basics—A Guide to Living Without Hookups, which covers a full range of dry camping topics. Visit icanrv.com for more information.