RV Propane 101 Cover Featuring Travel Trailer near Mountains

RV Propane 101: How Does My RV's Propane System Work?

(Your Practical Guide to Staying Warm, Keeping Food Cold, & Not Blowing Up Your RV)

RVers know that propane is a huge deal. It runs your furnace, keeps your fridge cold, and powers your outdoor kitchen. But when it comes to the actual setup and how it functions, propane is a subject most RVers have questions about from time to time. Maybe you want to know how much propane your appliances use and how freely you can use them. Maybe you just want to know how this whole propane system works and how to stay safe while using it.

Whatever the case, we've answered the most common questions we receive about RV propane systems below.

Here's the slice of RV life you'll learn about in this article:

How Does My RV's Propane System Work?
How to Fill an RV Propane Tank
How to Find a Propane Leak in an RV
How to Tell If Your RV Propane Tank is Empty
How Much Propane Does Your RV Use? (Furnace, Fridge, Water Heater)
How to Connect an RV Grill or Other Accessory

How Does My RV's Propane System Work?

RV propane systems can be complicated, but their overall operation is quite simple. High-pressure propane flows out of the tank into a regulator. There, the regulator reduces the gas to a controlled, low-pressure flow to be used for propane appliances.

You can also use a propane tee (or T-fitting) to hook up an extra propane tank and/or another accessory, like a gas grill. These tees are usually installed between the tank and the regulator. For more help expanding your propane setup, check out our guides to hooking up an external propane tank (here) or grill (here).

Your setup will be a little different depending on whether you have a motorhome or travel trailer/fifth wheel. Generally, motorhomes use built-in ASME propane tanks (regulated by the American Society of Mechanical Engineers), whereas travel trailers and fifth wheels use removable DOT tanks (regulated by the Department of Transportation). Smaller travel trailers/fifth wheels will use one tank, while larger campers will usually have two.

Why does this matter? ASME and DOT tanks function similarly, but you will see slightly different fittings used on these tanks, and you may have different options when it comes to refilling them. We'll go into more detail on these differences below.

Motorhome Propane Systems

Propane systems found on motorized RVs use a permanently mounted ASME tank to hold propane. These tanks are able to hold larger amounts of propane than the DOT cylinders used on other camper types. Typically the fill valve, regulator, and optional tee fitting are located at the propane tank on a motorhome.

What the Setup Looks Like:

Motorhome Propane System Diagram with Labels

Components to Be Familiar With:

1. POL to 1/4" NPT adapter: Connects LP tank to regulator or T-fitting.

2. Optional Propane Tee: Lets you connect an extra propane tank or accessory like a grill or fire pit. Usually installed between the tank and regulator.

3. Regulator: Ensures safe, controlled gas flow.

4. Supply Hose: Connects propane tank to RV's gas piping system.

Travel Trailer/Fifth Wheel Propane Setups (Single Tank)

Typically found on pop-up campers and small travel trailers, single-tank setups use one DOT propane cylinder, usually either a 20-lb or 30-lb tank.

From the tank, propane travels through the pigtail hose to a dual-stage regulator. After the regulator, propane enters the supply hose (or trunk hose) and is distributed to your propane appliances.

What the Setup Looks Like:

Single Tank Trailer Propane System Diagram

Components to Be Familiar With:

1. Optional Propane Tee: Lets you connect an extra propane tank or accessory like a grill or fire pit. Usually installed between the tank and regulator.

2. RV Pigtail Hose: Used on DOT tanks on travel trailers and fifth wheels. Allows you to connect a propane tank to regulator or T-fitting. Single-tank systems use one pigtail hose, while dual-tank systems use two.

3. Regulator: Ensures safe, controlled gas flow.

4. Supply Hose: Connects propane tank to RV's gas piping system.

Travel Trailer/Fifth Wheel Propane Setups (Dual Tank)

Dual-tank DOT propane cylinders are found on most travel trailers and 5th wheel campers. These campers have larger appliances and more of them; for instance, you may have an outdoor kitchen or larger furnace. On travel trailers, propane tanks are typically stored at the front of the trailer, on the frame between the trailer and coupler. On 5th-wheel campers, tanks may be stored in a single storage compartment, or they may be split so that one resides on each side of the camper. (In this case, a long pigtail hose will run from the far-side tank to the regulator.)

You'll only use one tank at a time, so when one runs out, you can refill the empty tank while using the propane in the backup. If you have an automatic changeover regulator, your setup will automatically switch to the backup propane tank when the first one runs out, provided you leave both tanks open. If you have a manual changeover regulator, you'll usually move a lever to switch between the tanks.

What the Setup Looks Like:

Dual Tank Trailer Propane System Diagram

Components to Be Familiar With:

1. Optional Propane Tee: Lets you connect an extra propane tank or accessory like a grill or fire pit. Usually installed between the tank and regulator.

3. Regulator: Ensures safe, controlled gas flow.

4. Supply Hose: Connects propane tank to RV's gas piping system.

How Does an RV Propane Furnace Work?

In terms of what you actually have to do to make the furnace work, it's pretty straightforward. When you get to the campsite, slowly open your propane valve all the way. Then, set your thermostat inside to your desired temperature. Your RV may also require you to manually light the furnace pilot light (read more about how to do that here.)

Your RV propane furnace uses a forced air system that requires both propane and a sufficiently charged battery to function properly. If your furnace isn't igniting, you'll first want to check that you have enough propane and that your battery isn't too low.

Here's how it works:

1. The temperature falls in the RV; the thermostat tells the furnace's circuit board to turn on.

2. The circuit board turns on the fan and gets spinning at the proper speed (this won't happen if the battery is too low).

3. The sail switch allows the furnace to ignite once enough air is moving from the fan. (The sail switch prevents the furnace from igniting prior to having sufficient air flow.)

4. The propane-fueled flame heats the air, which is then forced through the ducts by the fan.

How Do You Run an RV Fridge on Propane?

Start by slowly opening your propane valve all the way. Make sure your fridge is set on the propane or automatic setting. (Automatic settings typically tell the fridge to use electricity when it's available and propane when it's not.) Many RVers prefer to turn their fridge on the day before their trip to cool give it time to cool down. No one wants a warm beer or melted ice cream at the campsite!

Most modern RV fridges ignite automatically, so you won't have to light the pilot light yourself. But if you have an older RV, it's possible (albeit rare) that you'll need to light it manually. Learn how here.

Note that RV refrigerators are temperamental and won't work properly if they're unlevel. Therefore, it's important to make sure your camper is always level when you're at the campsite and using your fridge. (Read more on leveling your camper here.)

Driving Your RV with the Propane Fridge On: Is it Safe?

This is one of the most common RV-fridge questions we get. And the answer is: you are assuming some extra risk, but you'll most likely be fine.

For the record, many propane suppliers, RV fridge manufacturers, and even insurance companies recommend keeping your propane off while you drive. You're not opening your fridge and letting the cold air out while you drive, so most fridges will keep your food reasonably chilled between campsites.

However, we'd venture to say that most RVers with propane fridges do drive with them turned on at least some of the time. The main risk is a line breaking and triggering an explosion in the event of an accident. Is this unlikely to happen? Statistically, yes. Just be aware that it is a possibility, and you assume the risks when you drive with propane on. We advise you to check any laws in your state before traveling.

Remember that you'll have to shut your propane off in some circumstances no matter what:

Shut off your propane and appliances when you refill your propane tank.
Shut off your appliances when at the the gas station. If you only turn off main propane line and not your appliances, they might try to reignite the pilot light, and you don't want an open flame burning at the gas station.
Check your state's restrictons on tunnels, and keep an eye out for signs that prevent bottle gas in tunnels. Why the concern over tunnels? Propane weighs more than air, and there's a risk of gas pooling at the bottom of tunnels and creating a hazardous gas tube. You may be allowed to pass through by simply turning your propane off, or you may have to find an alternate route.
Of course, shut off your propane anywhere a state or local law prohibits propane use while driving.

How to Fill an RV Propane Tank

When your propane tanks run low, it's time to either exchange or refill them. If you have a 20-lb tank (the same kind you use for a gas grill), you can typically exchange these at Home Depot, Walmart, or another propane exchange location.

If you have a 30-lb or 40-lb DOT tank, or if you have a motorhome with an ASME tank, you'll have to refill the tank rather than exchange it. You can also refill your own 20-lb tank if you choose. You can find designated propane refill stations at many RV parks, truck stops, U-Haul locations, Camping World dealerships, and some gas stations. A quick internet search should pull up propane refill stations near you.

To actually remove your tank (this only applies to DOTs, not permanently mounted ASME tanks on motorhomes), first make sure the valves are closed. Disconnect the pigtail hose from the tank (twist off the large green or block knob). You'll most likely have a wing nut or bar that holds the tank in place; remove this, and lift the tank from the camper. Remember that wing nuts on propane setups are left-handed threads, so you'll unscrew them clockwise.

So what happens when you go to refill a propane tank? First, make sure the gas is off. The attendant will make sure your tank isn't expired and perform a visual inspection of the tank. If it's in good shape and considered safe to refill, the attendant will then refill it for you. Some campgrounds even offer a propane refill service, where an attendant will come to your campsite and refill your tank if you need it.

It's important to remember that propane is gas, and as such, it can be dangerous if you don't treat it with proper caution. This is why it's usually best to let a trained propane attendant fill your tank for you.

Label showing disconnect location on propane tanks (at green knobs)

Exchanging Tanks

PROS

Highly convenient - can typically do this at any Walmart or hardware store
Can trade out your nearly expired tank for a new one

CONS

Typically costs more than refilling
May not receive a completely filled tank in exchange
May end up trading your newer tank for an older one in worse condition
You don't know how well the tank you receive was cared for by the previous owner
Limited to 20-lb tanks in most exchange locations

Refilling Tanks

PROS

Typically costs less than exchanging
More control over the amount of propane in your tank
Can keep your own tank in great condition and use it for years
Typically the only option for tanks larger than 20 lbs

CONS

May not be as easy to find a refilling location as it is an exchange location
DOT tanks must be recertified every 10 years since you'll be using the same tank

How to Find a Propane Leak in an RV

We always recommend using a gas detector in your RV. But you also have another reliable propane leak detector on board: your nose. If you do smell the telltale stench of rotten eggs, you likely have a gas leak. (The manufacturers add this smell deliberately as an added precaution.) You may also have a leak if you start going through propane much faster than normal, or if your appliances aren't lighting or have a low flame.

You can also test for a leak using a soapy water solution. Mix liquid soap and water in a spray bottle, spray the solution onto your propane lines, slowly open the tank valve, and watch for any bubbles that appear and indicate the leak location.

If you do have a leak, here's a quick rundown of what to do:

Immediately turn the main propane valve to "off" if possible.
Cease using your gas appliances and put out open flames; turn off lights; don't even risk using your cell phone near the RV. Even the smallest spark can turn dangerous when there's a gas leak.
Open the doors and windows.
Put as much space between yourself/your family and your leaking gas tank as possible.
If you have campground neighbors, make sure to warn them too so they can take precautions.
Once you're a safe distance away from the RV, call 911.

Pictured: a potentially life-saving RV propane gas detector

How to Tell If Your RV Propane Tank is Empty

Of course, you could wait and find out when all your appliances stop working. But you'd probably like to find out before you're left with a cold shower or melted food. Here are a couple ways to check if your tank is running on E:

The easiest way is with a propane tank gauge like this one. It will let you know how much LP you have left and even detect leaks.
Another simple method is to pour a pot of hot water on the outside of your propane tank. No, this isn't a joke — feel the tank afterward, and where the tank is hot, it's empty. The cold part of the tank indicates that it's filled with propane. Similarly, if you're camping in a cold climate and part of your propane tank is frosted over, the propane is usually where the frost is.

How Much Propane Does Your RV Use?

If you've never used propane while camping before, you might not know what to expect as far as how much propane you'll actually use. And like with most RV-related questions, the answer to this one is "it depends." If you're camping in cold weather and constantly running your furnace, you're going to guzzle gas like your favorite soft drink. If you're camping in mild weather and just running your fridge, it'll probably be weeks before you have to refill.

So how can we be more precise when estimating propane usage? We can look at the BTU rating of our appliances.

Each gallon of propane equates to 91,500 BTUs (British Thermal Units). If you know the BTU rating of a given appliance, you can estimate how much propane you'll need. For reference, a 20-lb propane tank holds about 4.6 gallons of LP. This is 420,900 total BTUs. Add up the BTU rating for each of your propane appliances and the hours per day you'll run them, and you'll get a rough estimate of how long your propane will last.

For instance, if your furnace is rated at 30,000 BTUs, it will use 30,000 BTUs (or 1/3 of a gallon) after running continuously for an hour. After three hours, it will use 90,000 BTUs, which is just about one gallon of propane.

Of course, you probably won't run your furnace continuously for an hour at a time. And you'll probably be running other appliances in the meantime. The more you camp, the better idea you'll form about how much propane you actually use during your trips, and the less you'll have to rely on math and rough estimates.

How Much Propane Does an RV Furnace Use?

*Biggest propane drain

RV furnaces usually use about 1 gallon of propane to run for 3 hours. Of course, the temperature outside, the temperature you set your thermostat at, and how often you run the furnace plays a big part in how long your propane tank lasts. But in general, an RV furnace will use up a 20-lb propane tank in about 13.8 hours. This is total runtime; you probably won't be running it continuously, so this runtime will be spaced out over several days.

Propane Usage Chart (20 lb tank = 13.8 hour furnace runtime)

How Much Propane Does an RV Hot Water Heater Use?

*Medium propane drain

Again, this will vary quite a bit. The best way to figure out how far your propane will take you is to just camp and keep track of it. You may want to bring a small bottle along for backup propane.

Some RVers leave the water heater off and turn it on about twenty minutes before showering. This does conserve a bit of propane, but not much. In our opinion, it's more convenient to just leave the water heater on so you have hot water when you need it, unless conserving propane is really important to you (such as for an extended boondocking trip).

Many RVs now come with a tankless water heater, which runs on about 50% less propane than standard water heaters.

How Much Propane Does an RV Fridge Use?

*Least propane drain

Compared to RV furnaces, RV refrigerators don't use much propane, particularly the newer/more efficient models. After a couple days, you may look at your propane gauge and wonder if it's working right.

On average, most RV fridges only burn about 1/4 to 1/5 of a gallon per day, or about 1 lb per day. This figure is even less if you partially run the fridge on shore power.

How to Connect an RV Grill or Other Accessory

There's nothing like an old-fashioned BBQ at the campsite. If you have a propane grill, you may wish to run it off your RV's propane tanks rather than carry around extra bottles.

Generally speaking, you can connect your grill to your RV propane setup in one of two ways: either connect directly to a Quick-Disconnect (if you've got one) or tee into the propane system with a T-fitting.

The main issue people run into when hooking up a grill is that some grills come with regulators, and most campers come with regulators, and you can't have the gas flow through two regulators or the flow will be too weak to use. If your grill doesn't have a regulator, tee into your propane setup after your RV's regulator so you're only using regulated gas. If your grill comes with its own regulator, tee into the propane setup before your RV's regulator, so the gas only flows through the grill's regulator.

We promise it's not as confusing as it sounds — check out a more detailed explanation with diagrams here.

Other accessories, such as firepits, work the same way. Many campers come with Quick-Disconnects that run off the main propane line (you can always add one if yours doesn't). Connect to this port, or tee into your propane setup to run a hose from your RV to your accessory.

Still have questions?

Give our experts a call at 800-298-8924, or contact us online. We're happy to assist any way we can!

About the Author

As a content writer for etrailer, I might spend my morning loading and unloading a bike on five different bike racks to figure out which is easiest to use. I might be in the parking lot, taking pictures of an impressive RV battery setup our techs came across in the shop and discussing the benefits of the setup with the owner. I might spend an afternoon in a manufacturer training class for some hands-on experience with new products, and then sit down to assemble all this information into a coherent article.

At etrailer, one of our core values is that we are always learning, and I learn something new every day. I start each morning with the goal in mind of taking all of this information and figuring out the best way to answer the questions people ask us (and the ones they don’t know to ask yet), and helping people get the solutions they need to make their lives easier, safer, and more fun. I’m a DIYer at heart, so it brings me great joy to help a fellow DIYer find what they’re looking for, whether that’s a product, an answer, or a community.

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