Does Furnace Run on DC Power??

The blower fans are the power hog. In some rigs, a blower for a 35,000 BTU furnace can pull as much as 8 or 9 amps. One blower circulates the air inside the rig. The other blower brings outside air into the comustion chamber and back out the vent.

Setting the blower to use the lowest speed possible will extend battery life.

manualman wrote:
Why are full size RV furnaces such power hogs? Our popup furnace will keep our camper (24' when open) at 50 degrees overnight when the outside is 30 for 4 to 5 nights (off in the day) on one G29 deep cycle! And we have ZERO insulation with those canvas walls. Just how hot you guys trying to keep it in there? And why? Get some blankets.

Or maybe popups just have magic furnaces...

popups have way less power drains than other RVs.

YES

I left my thermostat on when storing my first TT once. Went back to check on it about 6 hours later. Two big batteries deader than my first marriage.

manualman wrote:
Why are full size RV furnaces such power hogs? Our popup furnace will keep our camper (24' when open) at 50 degrees overnight when the outside is 30 for 4 to 5 nights (off in the day) on one G29 deep cycle! And we have ZERO insulation with those canvas walls. Just how hot you guys trying to keep it in there? And why? Get some blankets.

Or maybe popups just have magic furnaces...

The ducting is bad and it draws 2x the battery power(or more).
I assume your PUP furnace vents direct to the living area.

I ended up adding two additional vents to get some heat into the trailer.

Why are full size RV furnaces such power hogs? Our popup furnace will keep our camper (24' when open) at 50 degrees overnight when the outside is 30 for 4 to 5 nights (off in the day) on one G29 deep cycle! And we have ZERO insulation with those canvas walls. Just how hot you guys trying to keep it in there? And why? Get some blankets.

Or maybe popups just have magic furnaces...

I found out that one group 24 won't run the furnace through the night with a 24' camper. I have bought a second group 24 to add, but I'll have to modify the battery rack to squeeze it in. Seems odd that the toy hauler manufacturer made a battery rack that won't hold two group 24 batteries with battery boxes.

I'll hook up the generator next time I try it, just in case the two of them together won't make it through the night.

When we bought our first motorhome (Class A Pace Arrow), we immediately learned that an 8D battery, fully charged, will be dead by 3 AM running the furnace.
For those who don't know, an 8D battery is one of those 12 volt units that is a little bigger than 2 group 24 batteries!
Getting up at 0300 to start the engine so you can start the generator, in 35 degrees temperature, is NOT fun!
But, to directly answer the question, YES, 12 VDC power and propane are the only things necessary to run the furnace.

BigSur2 wrote:
A friend and I are planning a trip where we might have to stay overnight in a parking lot the first night in. We both have TTs. Can we run our furnaces off of DC Power?

In case you don't know, the furnace runs ONLY on 12vDC power, not shore power.
The furnace fan and lighting are 12vDC. Shore power only recharges the battery.
Of course you also need propane.

Bobbo wrote:
We found out in 2011 while in Yellowstone National Park in November, that we had to have the heat turned down to 50 at night, or the 2 batteries would be dead by 2am. We learned to snuggle under the comforter, and turn the heat back up in the AM.

That is exactly the place I learned about running the furnace & batteries.
As a NewB in '08 we were at Madison CG, it got down to 30F, so we ran the furnace at about 65 all night, sometime in the early AM, DW noticed that the furnace was no longer running, granted, it was only 2 27 series batteries, but they were dead in the morning,
As a side note, this is also where I learned about the Altitude adjustment on the Onan generator. :B

Thanks again folks. All great information.