Keeping Warm Off the Grid

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{mosgoogle left}Monstrous Consumer
The typical RV furnace chews up a lot of propane and electricity. You can thank old-style thinking, based on “stix and brix” home furnaces. The idea is to heat up a volume of air in the firebox, circulate cool air over the outside of the box (or a heat exchange system), and blast the heated air throughout the RV with an electric fan, which most often consumes monstrous quantities of power.

Meantime, outside the rig vast amounts of heat are discharged into the open air. Those armies of British thermal units aren’t doing much to heat up the outside air, but they do tend to warm you up when you see how much it costs to fill your propane tanks. All in all, RV furnaces aren’t super efficient.

The greatest concern to those staying outside the reach of the shore power connector at an RV park is how much electricity the RV furnace consumes. Even a non-ducted furnace (like those that heat a small truck camper or pop-up) chews up about 5 amps per hour. The larger the rig, the larger the furnace fan, and of course, the greater the power consumption. Very early on in our RVing experience, when our rig didn’t have a “house” battery, but drew power from our truck’s ignition battery, just a single night of cool-weather camping left us looking for a jump-start. A “factory” furnace is great for taking the chill off, but it’s just not the thing for extended boondocking. Enter the alternatives.

Here Kitty-Kitty!
A cat heater may be what you’re looking for. Yes, it will keep your feline friend warm, but we’re more in mind of a catalytic heater. These little fellows are flameless units that produce gobs of heat without using any electricity. Powered by propane, they’re highly efficient, turning most of your LP buying dollar into heat—about 95 cents worth or more of it coming into your RV.

Cat heaters are relatively small, can be mounted on a wall, or if you like, with optional feet can be placed on the floor and pointed in the direction where you most want heat. These are radiant heaters, and do a bang-up job of warming anybody standing in front of them. However, they do take longer than a forced-air furnace to transmit heat to other parts of the rig. That’s because of their nature: They warm objects first, then the heat from those objects (like floors and walls) radiates out to warm the surrounding air.

Cat heaters do have their drawbacks. They obtain their oxygen for combustion from the air inside the RV. Because of their high efficiency, they don’t use nearly as much oxygen to produce the same amount of heat as would an open flame heater.

Nevertheless, it’s important to follow the manufacturer’s precautions about providing air—cracking a window, for example. And because cat heaters don’t “exhale” outside, a byproduct of LP combustion—water vapor—is likewise released into the RV. If RVing in a high-humidity area, you’ll be adding more moisture to your air.

Another drawback is that most cat heaters don’t have a “demand” thermostat, that is to say, you can select a level of heat from the unit (typically low, medium, and high), but they don’t cycle off and on to meet heat demand. Once on, they’re on until you reset the heat production level or turn them off.

Blue Flames and Bricks

{mosimage}There is another class of non-vented heaters, many of which do provide a demand thermostat. Freestanding flame heaters, often referred to as “blue flame type,” are very big on the snowbird circuit. Most of them allow a view of the flame behind safety glass, so it’s like having a miniature fireplace in your rig. They too are highly efficient with their use of LP, and don’t require electricity to operate.

As with cat heaters, you need to be cautious about providing sufficient combustion air to your blue flame heater. Many are equipped with a low oxygen sensor that shuts the heater down if the oxygen level in the rig falls to a point that would endanger human life. If you travel to higher elevations, the sensor may not allow the heater to operate, but don’t try to defeat its purpose!

Other non-vented heaters somewhat similar to the blue flame style are brick heaters. These little heaters have one or more ceramic “bricks” containing tiny orifices. The LP flows through the orifices and burns off on the surface of the ceramic. We don’t think they’re nearly as cute as a blue flame, but they’re less expensive and heat well.
Alternative Heater Maintenance

Happily, most of these alternative heaters require little maintenance. The catalytic bed of a cat heater is susceptible to air pollution and dust. It’s best to keep your cat heater covered with a vinyl cover when not in use. Fuel-borne pollutants can raise problems by clogging tiny orifices that feed the cat bed. We had to send one of our cat heaters back to the factory to have its plumbing cleaned out after we’d gotten into a bad batch of LP. One major manufacturer recommends not burning LP obtained from Mexico as they say their experience is that South of the Border LP can contain more contaminants than that sold stateside.

If you use a cat heater, it may be wise to have your LP tanks purged by an LP dealer once a year to ensure any gunk you’ve picked up is removed. Compared to the cost (and hassle) of having to send your cat heater in for service, it’s cheap insurance. Repairing clogged cat heaters is not a do-it-yourself proposition. DON’T touch the cat heater catalyst bed, and don’t try to vacuum clean it. It’s a sensitive little critter and easily damaged.

Blue flame heaters with oxygen sensors can be susceptible to the buildup of dust. The blue flame in our fifth wheel occasionally gets balky and refuses to light. That’s a sign to us to get out a “can of air” like that used for cleaning computer keyboards. We blast the stuff through the oxygen sensor, and off we go again. If you buy a used cat heater, be sure to get the instruction manual to know how to perform this operation.

A few other tricks for staying warm in the winter: Never underestimate the power of a warm sweater. Orient your rig so the broad side is aimed at Old Sol. We don’t recommend using the stovetop as a heat source. It can prove dangerous to your health, and heating up the “pan grids” without a pan on them to absorb the heat can cause them to distort, or even break.

And speaking of distortion, if you’ll allow us to borrow (and slightly twist) a quote from an unknown source, we leave you with this thought:

“Winter is the season in which people try to keep the RV as warm as it was in the summer, when they complained about the heat.”

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.  They also provide great resources in their book, Camp Hosting USA—Your Guide to State Park Volunteering.  Visit for more information. 

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Written by Russ and Tiña De Maris
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