Who doesn’t fancy a warm cozy rig when parked in the middle of their favorite camping site? Most overlanders and off-road enthusiasts tend to rely on shore power to enjoy all the onboard amenities and live their off-road lives like normal. Then there are people who go totally off-grid, living completely off of their RVs. This is called boondocking and it requires your RV to be a real motorhome.
Once you have nothing but your RV’s power, things are going to get tricky and tough. You become totally reliant on your vehicle for all your needs, especially heating and staying warm on cold winter nights.
If you’re concerned about your RV furnace running on battery and planning to go boondocking, it is important that you read through our comprehensive guide and prepare yourself for that hardcore trip.
How Does an RV Furnace Work?
Your RV furnace actually uses propane to run and generate heat. But it also uses a blower to dissipate that heat so that you could use it to keep your RV warm and cozy.

Most RVs come with a 12V battery and although the furnace won’t even blink with this menial power, the blower would run just fine. And you actually need the blower to keep running and keep the interior warm.
A furnace typically uses 8 amps per hour and your RV battery is rated at 12V 100 amp hours. In simple terms, if your RV comes equipped with 2x 12V 100 amp batteries, you would have 200 amps of power available.
If it’s a lead-acid battery, you can’t let it drain below 50%, so you could only use 100 amps carefree. Also, remember that other appliances and accessories are using the same battery over time.
How Long Could You Use the RV Furnace with a 12V Battery?
With smart planning and economical usage, you could make your RV furnace run for more than a day continuously, without losing power.
Theoretically, if you’re just running a furnace and nothing else on your RV, it would consume 8 amps per hour and run for 12.5 hours straight. We also consider that nobody is going to run the heater all day and night, and with no backup nearby, everybody is going to act smart and frugal about it.
Normally, you would be running your RV furnace for 20 minutes per hour and by this logic, your RV heater would run for nearly 40 hours (37.8 hours to be precise) and keep you warm for enough time to keep going into the adventure.

How to Make Your Batteries Last Longer While Running an RV Furnace?
To make sure that you don’t run out of power and get stranded out there while boondocking, follow these simple steps and make your RV battery run for extra hours.
Lower the Thermostat at Night
When getting all packed up to sleep, it is better to turn the thermostat down. You don’t need your RV boiling up when going to bed and it only needs to be cozy enough for a comfortable sleep.
Turning down the thermostat saves a lot of power and keeps your batteries running for a longer duration.
Turn off the Heater During the Day
You don’t need the heart running all day and mostly you’d be out exploring the wilderness with your friends. Turning off the heater and even disconnecting the batteries make sure that they don’t get drained when not in use.
Keep it Sleeping When not in Use
Whenever you’re just sitting around and having a nice time, it is important that you turn it off and unplug the switches. This would help you prolong the battery’s power and lifespan for good.
Cover Yourself
This is the most economical way of staying warm and extending your battery’s life at the same time. When loading your stuff, remember to pack all the necessary winter apparel like jackets, sweaters, and caps for staying warm, without having to use an RV furnace all the time.
Insulate the RV
Keeping the heat from escaping and the cold from getting in your RV is the easiest way to stay warm and prevent battery drainage. You have to cover all the vents and exits, particularly the windows and the roof vent. Using a carpet to insulate the floor also prevents the heat from escaping and keeps your RV warm.

Control the Thermostat Manually
Manually controlling the thermostat helps you regulate the temperature precisely, and helps you run the furnace economically, and prevent the batteries from running out.
Check the Ductwork
This is another important consideration to keep your furnace working efficiently and prevent loss of heat. If the ducts are leaking or not connected properly, you’d be wasting the batteries and propane altogether. Get all the parts of the assembly checked before embarking on your boondocking adventure.
Park Under Direct Sunlight
If you’ve enough sunlight getting inside your RV, you won’t need to run the furnace or use those batteries at all. This is the easiest most economical way of staying warm during winter boondocking.
Get Solar Power
The easiest way of heating the RV without draining the batteries is switching to solar power. There are portable and smart solar panels available that you can easily set up on your RV rooftop and save yourself from the hassle of generators and pollution.

Use Generator When Required
Needless to say, when you have no other option left, a generator would save the day for you and charge the batteries. A propane generator is ideal for that as it is silent in running and doesn’t release any toxic gases.
Verdict
It is an excellent and practical alternative to using your RV’s battery to power your furnace, but you shouldn’t depend exclusively on the battery to keep your RV warm and cozy. To assist you in maintaining the ideal temperature in your camper, you can employ several additional backup solutions, such as portable solar panels or a propane generator.
To ensure that you won’t be left out in the cold while exploring beautiful nature, you can also assist conserve your battery’s life by using warm clothes, reducing the temperature at night, and making excellent use of strong daylight.
Citations
https://www.rv.net/forum/index.cfm/fuseaction/thread/tid/24588130/print/true.cfm
https://www.irv2.com/forums/f50/how-long-will-furnace-run-off-battery-401310.html
https://www.rvforum.net/threads/furnace-only-works-on-battery.70922/
Ever since I was a kid, I've been fascinated by travel. I inherited this passion from my parents. Since my college years and to this day, I have had a passion for traveling in a motorhome. I am here to share my experiences with you.