An RVer wrote us that she’s planning a trip from Texas to the higher elevations of the U.S. and wondered if there are any issues that she might face with her RV. High-elevation RV travel can and does present some challenges. We’ll tell you about them, and how to “fix” what you can.
High-elevation propane issues
Propane-operated appliances may be the first issue that comes knocking on your door. High-elevation travel can lead to erratic operation, or even non-operation of water heaters, refrigerators, and furnaces. Here’s the principal reason: The higher you travel, the less gravity pulls the oxygen molecules, and the air becomes “thinner” in that there are fewer oxygen molecules in the same amount of air at lower elevations. What happens?
Here’s a lift from an RV refrigerator owner manual: “All gas appliances experience lowered efficiency (or rating) at high altitude This is a direct result of lower atmospheric pressure and oxygen levels, and is not a defect of the refrigerator. Reduced cooling performance and burner outage may occur at altitudes higher than 5500 feet above sea level (while operating on LP gas). Always operate refrigerator on electric power at altitudes higher than 5500 feet.”
All well and good, provided you can operate your RV refrigerator on electric at a high elevation. If you’re parked somewhere that has shore power available, it’s not a big problem to plug in and keep cooling. But boondockers at high elevations don’t have that advantage. We’ve found our RV fridge ran just fine at 6,000 feet. However, once we got higher, the chill doesn’t always come as readily. We haven’t experienced “burner outages” even at 8,000 feet and, happily, the ambient temperature kept us going well enough.
Water heaters and furnaces
As to refrigerators, there isn’t much to be done to adjust for higher-elevation travel. This isn’t necessarily the case for RV water heaters. Your water warmer’s manufacturer may be able to provide you with a jet with an orifice rated for the altitude range where you travel. If you are fairly competent at wrench twisting, changing out the jet isn’t a big deal. However, if you won’t be long at the higher elevation, it may be more of a bother. Some have found that if their water heater isn’t running so hot, opening the access door was all they needed to do to improve the situation.
The same holds true for furnaces. You just may be able to obtain an appropriately sized jet for your house warmer for higher elevations. However, accessing the jet on the furnace can be a real bear of a chore. If you use a catalytic or “blue flame” heater, operations at higher elevations can be tricky. These efficient heaters often are equipped with an oxygen sensor as a safety feature. Get too high and your “Rocky Mountain High” comes to a crash when the heater simply shuts itself off.
Not all “LP” is propane
One more thing on the subject of LP. Our reader from Texas may find she has problems when she hits higher elevations and their associated lower temperatures. Not all “LP” is really propane. In some areas of the country, particularly where the temperatures rarely dip below freezing, you may be sold butane rather than propane. Butane under pressure is a liquid, just as is propane. Both liquids must vaporize, or turn into a gas, to be useful. But butane stops vaporizing a little below 32 degrees Fahrenheit, so it becomes useless in cold country. Ask your pumper just what they’re putting in your rig if you have any questions.
Germain to generators
If you use a generator in your high-elevation travels, you may have problems. Once you hit 500 feet above sea level, generator engine power decreases 3.5 percent for every 1,000 feet of increased altitude. We had an experience with a portable generator on one trip. Little did we know then, heat is also a “power killer.” Engine power decreases 1 percent for every 10 degrees in temperature increase above 85 degrees Fahrenheit. At our 5,000 feet of elevation on a 105-degree day, we were then 20 degrees above the magic number, meaning an additional 2 percent power loss. A total of 18 percent “less available” power.
We’ve switched generators now, and happily our new traveling companion (a FIRMAN) has three different jets. One that we principally use is good to about 5,000 feet. Two others can be switched out for higher-elevation traveling. It’s not real convenient; we have to yank off a cover and dig into the machinery to swap jets, so we tried to “fudge” on it recently. At 7,000 feet we “fired up the FIRMAN,” and it started easily enough. But the moment we put a load on, the Faithful FIRMAN flopped and died. We decided we could get along without the power for the day. You’ll find more information on high-elevation generator operating here.
Knock, knock. No joke!
There are a couple of other things about high-elevation RVing to be aware of. Knocking. No, not the kind you do when waiting for your teenager to get out of the bathroom, but that which your engine may do. This is particularly true for older-model gas engines. If you’ve been traveling at higher elevations, then come down toward sea level, you may be startled to hear an unwelcome engine knock. It’s all in the octane.
Octane ratings, a measure of gasoline’s ability to help an engine resist knock, may be lower at stations at a higher elevation. You may find “regular” gas in Colorado that has an 85 octane rating. Come on down to the lowlands, and regular is typically rated at 87. Fill up with 85, come down to the lower elevations, and the “knock, knock” is no joke. Check your engine owner manual to see what it recommends for minimum octane level. You may need to spend a bit more for the “mid-grade” higher octane-rated fuel. Read more here on the subject.
Finally, some RVers are concerned about tire pressure and high-elevation travel. Yes, the higher you travel, the higher the seeming pressure inside the tire. For those with tire pressure monitoring systems, this may seem alarming. But RVtravel.com tire expert, Roger Marble, reminds us things have a way of working out. Using an illustration of the difference in elevation—and temperature—between Denver, Colorado and Pikes Peak, Roger helps reason on the matter.
“If we needed 70 psi to support the load on a tire according to the tables, we would want to see 70 psi on both our hand gauge and our TPMS if we were setting the tire pressure in Denver. If we were to then drive to the top of Pikes Peak, the outside pressure has now dropped (12.2 – 8.59 = 3.61 psi).
“Remembering that our handheld gauge is reading the difference between the pressure inside the tire and the pressure outside the tire, that drop of 3.61 psi would mean our tire pressure was now 73.61 PSIG [gauge pressure], assuming no temperature change. But the reality is that Pikes Peak temperature is usually colder than Denver. When I was writing this up, the temperature at the mountain top was 40°F colder. In this post, we learned the effect of temperature on tire pressure was about 2% for each change in temperature of 10F. So once the tires were at the surrounding air temperature they had cooled off by 40°F. That means the pressure would have dropped by about 8%, so our tire inflation pressure would be about 67.7 psi.”
What’s that mean for an RVer’s reality? Roger’s rule is this: “Bottom line: In the real world, the increase in tire pressure due to higher elevation is offset by the decrease in tire pressure due to the drop in temperature. So my advice is to not get your shorts in a bunch and just be aware of the changes in the pressure readings of your TPMS.” You can read more on this topic here.
High-elevation travel in your RV can lead to some issues and difficulties. Still, the view from “up there” can be particularly rewarding. If the heights are too much for your RV, consider parking a little lower, and using the tow vehicle or toad car to catch the view.