Using and Maintaining Your RV
Stay Warm With Alternative RV Heaters Part 1
By Russ and Tina De Maris

Even folks who flee the north country and head south for the winter find themselves needing heat from time to time. Don't let anybody fool you, the Desert Southwest may be 'shirt sleeve' weather by day, but winter nights can be down right chilling.

Staying warm is a good trick for any RVer, but if you're a boondocker -- somebody who camps away from electrical hookups, keeping warm without killing off your batteries is a major trick.

Furnace Follies

The typical RV furnace chews up propane and electricity. That's because 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.

If you stick your hand near the outside exhaust port of your RV furnace, you'll find quite a bit of heat blasting by--enough to burn your hand. Lots of those little British Thermal Units coming marching out of your firebox, only to contribute to desert warming. A forced air RV furnace isn't all that efficient.

For the boondocker, the real problem is how much electrical power your furnace consumes. Even a small, non-ducted furnace system (like those used in truck campers or pop-ups) can chew up 5 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.

In our experience, a forced air RV furnace is best used when tied up to shore power, or for short spells to "take the chill off." Where does that leave you for keeping the place warm for extended times?

"Cat" Heaters

While our own four-footed cat 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.

A catalytic heater uses 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 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 only 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 your run a cat heater, so that the air 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. Susceptible to pollutants, if you frequent areas where air pollution is rampant, the bed won't last as long as it might otherwise. As well, contaminants from propane or propane containers can 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 guck 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. First, 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, Olympian recommends avoiding the use of LP produced in Mexico. The company says this fuel often contains contaminants that can clog orifices and damage catalytic beds.

Olympian also recommends that RV 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) if you run a catalytic heater, it's cheap insurance.

Some catalytic heaters (as well as some "blue flame" type heaters) have a 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 cat heater won't work. Be sure to ask your dealer about how high you can travel and still use your heater. Another disclaimer: Be sure to follow the manufacturer's safety information. Try not to become a negative statistic.

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 "cats" that do use a small amount of power to control heat output to keep things more comfortable if the inside temperature fluctuates. Still, we learned how to put up with the lack of thermostatic control and could usually tell at bedtime at just what setting to leave our cat heater.

Read part two of this series.