does the furnace run on 12v?

MOST rv's have a furnace that uses 12 VDC power to operate...but not all. Some motorhomes and destination/park models require 120 VAC to run the heat.

Well, all systems are different but usually, unless your battery bank is in poor shape, it is REALLY cold out or you prefer to sleep in tropical temperatures, you should be able to go all night without running a generator.

When I first picked up my coach at night in cold weather I stopped at a camp ground and didn't have shore power and the furnace shut down during the night. I didn't know that the 12v batteries had died and the furnace needed them to operate. That's your answer!

Running the onboard generator while you sleep can be a VERY bad idea, unless you have some means (Genturi or similar) to run the exhaust well away from the living area!
You could wake up very sick, or possibly even not wake up at all!
I certainly would not do it in my coach, and I am fairly certain the generator exhaust system is in good shape, but I don't trust electronic gadgetry well enough to bet my life that the carbon monoxide detector will work!
The very first Class A that we bought had a Group 8D battery for the coach. The outside temp was about 35 degrees, and the thermostat was set for 60 degrees. The battery went dead at 3 o'clock in the morning! I had to get up and start the engine to get enough power to start the generator! that was not a fun night!
What made it better was that the fishing in that Montana mountain pothole lake was GREAT!!

RoyB wrote:
Here is a simplified 30AMP Electrical Diagram for RV Trailers. Might give some insight on what does what with 120VAC and 12VDC usage requirements.

Roy Ken

That is a great flow chart. Do you have a link to it?

Your furnace will run off the battery but it may not last all night especially if the temps is really cold. You can try it for say 4 hours then get up to check the power meter to see how much is left so you don't run it down to zero. At that point, if it is more than 1/2 empty...run the generator or just run it all night to save a restless night.

RVs are 'self contained'.........meaning that 12V DC & propane work the necessities.
The lights, the water pump, the fridge, the water heater and the furnace

As long as the battery(s) are keep charged and propane tank filled the necessities will continue to work
Furnace is the biggest hog....12V DC & propane, then water heater, water pump and then the fridge uses the least.

Course RVs have morphed....the basics are no longer considered the necessities
AC Electric for some lights, fridge, water heater, A/C, microwaves etc.

brandonrv wrote:
Odd that my operations manual doesn't say anything about the AC or the furnace. I'm assuming it's propane furnace, just wondering does the fan usually run on 12v battery?

I bought this motorhome earlier this year haven't had it in the cold. Using it this weekend where it's going to be really cold, but don't have a place to plug in.

Wondering if I need to run the generator at night?


It's a winnebago vista 26he

You should have seperate manuals for the furnace and AC with specs.

Shouldn't have to run the generator all night; as others have said heat is from propane, while fan and controls are all 12 volt. It'll use whatever propane is needed to keep you warm, and it'll probably hit the battery hard to run the fan, so I suspect you'll have to recharge the battery the next day.

AC, on the other hand, is strictly 120 volts because it uses so much power, the typical RV house battery would power it for less than an hour.

Here is a simplified 30AMP Electrical Diagram for RV Trailers. Might give some insight on what does what with 120VAC and 12VDC usage requirements.



Roy Ken