RVhometown is reader-supported. When you buy through links on our site, we may earn an affiliate commission. Learn more

How Does an RV Propane Furnace Work? Everything Explained

Writen by Dane Heldt

Fact checked by Robert Clark

how does an rv propane furnace work

Today, RV campers can stay warm in their vehicle just as they do at home with a camper propane furnace. But the question is, how does an RV propane furnace work?

A propane furnace works like a heater to warm the inside of your RV. It creates hot air and blows it out through the ducts when the blower motor gets activated by the thermostat. Continue reading for more related facts.

A Brief Overview About RV Propane Furnaces

A furnace warms your RV to make it cozy during the cold days. Most of the time, this heating unit comes already built inside the RV. Since it only feeds on propane for power, there’s no additional cost involved.

What this furnace produces is dry air, meaning there’s no moisture buildup. Best of all, it pumps more heat compared to an electric model without needing a plug socket.

Are RV furnaces safe? Yes, they’re totally safe. There’s very little chance that any poisonous emissions infiltrate your RV space because, as we’ve said, the vents are outside. However, since propane furnaces do generate carbon monoxide, it’s crucial that your vents are set up properly.

The Different Parts of an RV Propane Furnace


The intake vents bring fresh air into the furnace. Meanwhile, the exhaust vents send the toxic gas out of the motorhome. The pathways which carry the heat from the furnace to different spots in the RV are called the heat ducts.

Throughout the system, the fans circulate the air — one bringing in the outside air and another to push the toxic gasses out. The burner, which burns fuel, is located inside the air exchanger.

If you got an RV propane heater with thermostat, you’ll see an automatic device that controls the furnace and allows you to set the desired temperature. The thermostat can be similar to what you actually use in the house, and some fancier models come with digital technology.

What this thermostat does is monitor the temperature inside the RV and signal the furnace to turn on/off. The thermostat urges the furnace to kick on when the interior gets too cold and shut down when the temperature reaches the desired level.

Propane and House Batteries – The Power Sources

The travel trailer furnace operation depends solely on propane to produce heat; it doesn’t have any electrical heating elements. A 12-volt DC power from your house batteries runs the propane igniter and the fans.

Because the lifespan of the battery depends on the battery type, your RV insulation, and other factors, I recommend having multiple power packs during long winter trips, so you don’t have to worry about freezing to death in your camper.

Moreover, you need to charge your house batteries to run the furnace properly. The best way of charging the house batteries is to run a generator or plug into shore power.

At the same time, you can’t run the furnace without propane.

How Long Propane Tanks Last?


Propane plays a significant part in the function of furnaces, so it’s only wise to prepare enough tanks to fuel the entire winter road trip. Typically, RV propane tanks come in two types – ASME and DOT cylinders.

ASME tanks or RV horizontal propane tanks are usually installed and mounted outside of the RV. One of the benefits of these tanks is that they provide a gauge to indicate how much propane is left in the tank. The size of ASME tanks may vary from 20 pounds to 80-100 pounds.

Unlike ASME tanks, a DOT cylinder tank can be removed when it’s time to refill it. This portable type has a size that ranges from 5-200 pounds, but the two most common sizes for RVing are 20 pounds and 33 pounds.

The average RV propane furnace runs on about 20,000-50,000 BTUs, depending on the size of the furnace. Obviously, a small propane RV furnace consumes less BTU.

Generally, a gallon of propane delivers 92,000 BTUs of power. So, if we multiply that by the tank’s total number of gallons, then divide by the BTUs consumed by the furnace, we’ll get the amount of BTU hours available.

Let’s say you have a 20,000 BTU furnace. The BTU hours available in your 33-pound (8 gallons) propane tank would be:

92,000 BTUs * 8 gallons = 736,000 BTU hours

736,000/20,000 BTU = 36.8 hours

This means that a 33-pound tank can fuel a 20,000 BTU furnace for more than a day if run nonstop.

Efficiency and Cost

Propane furnaces are around 70% efficient. The remaining percentage is due to some unavoidable systematic flaws. However, you get a higher efficiency when you run a non-vented heater.

In terms of costs, you can save money with camper propane heaters compared to their electric counterparts. Let’s apply mathematics to compare the electrical cost to every gallon of propane.

Propane is rated in BTUs/hour, while electricity is rated in kilowatts/hour (kWh). When we convert BTUs into kilowatts, we get an equivalent of 27 kilowatt hours of electricity for every gallon of propane.

Let’s say you pay $13 cents per kWh; 27 kWh of electricity will cost $3.51 (0.13 x 27= 3.51). As of 2021, our propane supplier is selling propane at $2.72 per gallon. Since propane is selling below $3.51/gallon, it’s cheaper than electricity.

You can make your own comparisons by using your electricity and propane costs.

Common Problems and How to Fix Them

Using RV furnace for first time might be a little overwhelming, so here are some helpful RV propane furnace troubleshooting tips to get you by.

1. No Heat

When you run the furnace, and you’re not getting any heat, make sure that the propane tank is turned on. If it’s on, remember to light your burner to ensure that you get propane flowing in your device.

You probably have a problem with the sail switch if there’s no heat while the fan is running. The sail switch might stop the ignition of the furnace when there’s no proper airflow. Moreover, sail switches can also malfunction when they’re clogged with dirt and dust.

When the fan is not running, but no heat is produced, the battery might also be the culprit. The fan won’t work when the battery doesn’t produce enough voltage. Use a multimeter to check the voltage.

2. Pilot Won’t Light

Again, check if you have enough propane. If there is, the thermocouple might be the problem. Make sure that the thermocouple is in the right position in the burner and remove any insect webs if there’s any. You should also use spider spray periodically so these insects don’t hover near your furnace.

Replace the thermocouple if it has gone bad. Use the same model to avoid further problems.

3. Has A Foul Smell

Don’t be alarmed when you smell something awful when you turn on the furnace. This is normal when you’ve not been running the unit for too long. However, you might want to check the toxic gas sensor when you’ve been using the unit regularly.


Hopefully, you no longer wonder “how does an RV propane furnace work?”

To make the furnace run efficiently, make sure to pack enough propane tanks for your road trip and charge your house batteries.

Let us know your experiences with RV propane furnaces in the comments below. Please share the article if you like it.

5/5 - (3 votes)