By Russ and Tiña De Maris
In Part 1 of our little primer on propane, we talked about the nature of propane gas, and made a few points about taking care of propane storage cylinders. We’re back again to postulate on other propane peculiarities.
How much LP do you use?
Using a leak detector is less messy than soap, but either can help you stay safe. LP gas is a highly concentrated substance – there’s an awful lot of energy packed into that little container. Just how much? Glad you asked! From the technical side, there are roughly 91,000 BTUs (British thermal units) in a gallon of LP. So how does this work out? The typical RV refrigerator burner runs off about 5,000 per hour. That would mean over 18 hours of full-blown operating time on a gallon – but, of course, unless you’re in a really hot climate, your fridge will be switching off and on.
Big consumers of propane are water heaters and furnaces. A 25,000 BTU (measured at input) furnace will run off five gallons of LP in that same 18-hour period. Into long showers? Keep in mind your typical six-gallon RV water heater eats up 12,000 BTUs at full blast. You’ll likely get wrinkle-skin before you run through a gallon of LP, but it does add to the tally.
While you can sit and compute with a calculator and specification information, most RVers can tell you with experience just about how long it’ll take to chew up their available propane supply. But if the cost of LP cuts into your lifestyle, here are a couple of things to try:
When in warmer weather, if your water heater has a standing pilot light, simply set the heater valve to “pilot” and let the pilot light keep the water warm. Some report that with judicious use of showers they can actually keep from lighting off that main burner and let the pilot do it all.
RV furnaces are notorious LP hogs. If you’re in the market for a new furnace, compare the input BTU figures to the output – if 85 percent or more of your heat is going into your RV, that’s pretty good efficiency. But to make your LP go almost 100 percent, consider using a “blue flame” or catalytic style heater – almost 100 percent efficiency, and no use of 12-volt power to run a blower fan.
Traveling with LP
A point to keep in mind while traveling is that not everything sold as propane is the same. In a few areas, particularly in parts of Mexico, the product sold as propane has a higher proportion of butane gas than that sold in most areas of the U.S. That’s not usually a problem, as higher butane content LP burns just as well as that made up with lesser concentrations of butane. A problem can creep up if you take the “more butane in the mix” LP to colder climates. Where the ambient air temperature is below freezing, butane will not vaporize correctly, which can leave you with an inoperative gas system. If you gas up in Mexico, you’re best off using up the load before you head to the colder areas of the states.
Now here’s where we get to stick our necks out: Do you run down the road with your LP gas valves open? We’ve never seen a definitive study, but some tell us they do. Others forswear having the refrigerator cold while motoring, telling us they feel a lot safer with the LP turned off. We used to be of the latter camp: If we were out of camp, the valves were closed. Then we started motoring through the desert country in summertime and found that here was an exception to our old maxim: “Keep the reefer door shut, it’ll stay cold enough.”
Yes, it’s nice having the food cold, and not fearing a case of food poisoning. At the same time, there is that bit of dread. The old “what ifs” keep flowing: What if we forget to shut off that refrigerator when we pull into a gas station, and the worst thing happens? What if we get pushed off the road by a big truck and we tip the unit over, and an LP line breaks? A disaster is the answer to both of those “what ifs.” Wherever possible, we prefer to run with our appliances turned off, and the gas valves closed. And in country with moderate summer temperatures, that’s doable. We’d rather not become a terrifying statistic.
In any event, should you decide to run with your valves open, then ALWAYS stop before you get into a refueling station of any kind (gas or LP) and TURN OFF any gas-fired appliances. Standing pilots or automatic ignition, either way, the pilot or the spark from ignition can really create an explosion hazard under the right circumstances.

Other LP safety concerns
It’s not a bad idea to go through the LP system annually to check out safety concerns. With a bottle of soapy water solution (heavy on the dish soap) or, our favorite, an LP gas sniffer, check all gas connections inside and outside your rig. Here’s a detector on Amazon. If you have (and know how to use) a manometer (gas pressure gauge), then check to make sure your LP gas regulator is doing its job correctly. Don’t have one? Call around and find out what RV service facility will give you a good rate to test your regulator, and give you some peace of mind.
While doing your LP safety walk-through, check out all gas-using appliances for insect encroachment. Some wasps think the odor of LP is like honey to their cousins. They’ll build little nests in RV vents, causing appliance malfunctions or, worse, allowing for a buildup of deadly carbon monoxide gas inside your rig. An RVing friend of ours, investigating a stubborn furnace problem on his fifth wheel, got a real surprise. As he put his face down to the furnace vent to take a closer look, the furnace attempted to light. A wasp nest in the vent finally gave way, just as the face got down to the same level. The resulting BOOM ensured that his heart was still capable of pounding at a high rate of speed.
LP gas is a wonderful tool for RVers. Use it with care, observe appropriate safety cautions, and you’ll have plenty of good times in your RV.
##RVT952
Stores like Home Depot, Lowes etc sell a “Leak Detecting Fluid” (commonly used by plumbers / pipe fitters) that I MUCH prefer to soapy water. This fluid is FAR more viscous and, when it is brushed over a pipe with ANY sort of gas leak, instead of “tiny bubbles” you may or may not see, the bubbles you’ll see will be the size of softballs. Said fluid is reasonably priced and, compared to “soapy water”, Leak Detection Fluid is, in my opinion, significantly more effective. Just my $0.02.
Is it safe to travel with a bird in a class b with a furnace and water heater that runs on propane. If there is a small leak can it kill the bird.
don’t forget that if you live in eastern flyover country like we do that unless your furnace is operating no heat is being generated in the underfloor to keep plumbing from freezing. you can “supplement” the furnace with other heat sources, but should never turn it off during freezing weather.
Question on Propane. What about using a product called GasStop? This is suppose to detect if there is a problem it will shut off the flow.
We always turn the propane off when we drive down the road. It has been our experience that putting the refrigerator on DC will keep it cool (though it is not very good for cooling down a warm one). Admittedly, we avoid very hot weather when possible, that’s an advantage of having wheels.
Re your mention of how much energy (91,000 BTU/gal) in Propane which seems to panic many people. They seldom look at their tank of gasoline which comes in at 114,000 BTU/gal (google it) and generally we carry far more gallons of gasoline than liquid propane. Diesel has even more at 139,600 but its much lower flash point makes it safer.
I always thought diesel had a higher flash point?
Diesel: 51.7 °C (degrees Celsius)
Gasoline: -42.8 °C (degrees Celsius)
But in a major accident, either fuel dripping on the hot exhaust pipe can lead to disaster.
Another test for leakage would be using one of the gauges that go between the tank and pigtail. Install the gauge,turn on the tank to activate the dial. Turn off any appliances,and turn off the tank. Wait for I don’t know how long and watch the dial. If it moves you have a leak. If it doesn’t you should be ok. Called a leakdown test. Quite reliable.
The debate will no doubt rage on re: gas on while traveling. But as for that old “What happens if we’re in a crash and a propane line is cut” the answer is “nothing.”. The safety valve in the tank will detect the high flow and shut off the gas, which is why we “ease” the gas on when opening a new tank.
I agree 100% But! If a line is damaged and is not leaking at a sufficient rate to trip the safety devices built into the valve, then a partial leak can occur.
Hopefully you are going to do a Part 3 and discuss the propane level gauge systems like the Mopeka system. Although it tends to go through batteries it’s wonderful to be able to monitor the propane tank levels including the grill at home. I can even monitor the tanks in my stationary 5th Wheel in the winter when I’m not there to call a service to do a refill. Great system.