Good Sam Club Open Roads Forum: Tech Issues: Furnace using too much propane
Open Roads Forum Already a member? Login here.   If not, Register Today!  |  Help

Newest  |  Active  |  Popular  |  RVing FAQ Forum Rules  |  Forum Posting Help and Support  |  Contact  

Search:   Advanced Search

Search only in Tech Issues

Open Roads Forum  >  Tech Issues

 > Furnace using too much propane

Reply to Topic  |  Subscribe  |  Print Topic  |  Post New Topic  | 
Page of 6  
Prev  |  Next

Mason Co, WA/Bullhead City AZ

Senior Member

Joined: 11/12/2008

View Profile

Good Sam RV Club Member

Posted: 03/29/22 03:37pm Link  |  Quote  |  Print  |  Notify Moderator

Don't know but if any storage doors were open or inside vents open all the way it doesn't help. the thermostat only turned down to 65 at night and during the day if the thermostat is calling for heat at times doesn't help either. I can see how the heater could burn up a lot of gas in a night.
You could call a mobile repair person to check it if you are not comfortable doing that.

Welcome to my home, that door you just broke down was there for your protection not mine.


Davison Michigan (East of Flint)

Senior Member

Joined: 07/04/2006

View Profile

Posted: 03/29/22 03:54pm Link  |  Quote  |  Print  |  Notify Moderator

What would cause the furnace to use more propane?

There are several answers. MOST of them are "Maintenance" issues
Some there might be an obstruction in the flame/exhaust path. this would reduce the ability of the furnace to heat. It might also cause an OVERTEMP shutdown or a fire so that's a serious one.

A better guess is air/fuel mixture (Air gate) it is adjustable.. now I know how to adjust it but.. I'm not comfortable giving instructions READ THE FINE MANUAL or better yet an even better manual or ask someone who knows. It's easy you need basically a screwdriver (Phillips on mine) fingers eyes and ears.

Last (This is not the furnace) Air leaks and/or poor insulation on the "House" (RV in this case)... A drafty house burns more propane.

Home was where I park it. but alas the.
2005 Damon Intruder 377 Alas declared a total loss
after a semi "nicked" it. Still have the radios
Kenwood TS-2000, ICOM ID-5100, ID-51A+2, ID-880 REF030C most times

Grit dog

Black Diamond, WA

Senior Member

Joined: 05/06/2013

View Profile

Posted: 03/29/22 04:31pm Link  |  Quote  |  Print  |  Notify Moderator

30' camper is way bigger than my experience, but most LP used was in our TC, camping in AK interior in the spring, with a drafty slide out (wasn't smart enough to run the slide in at night...). Daytime temps above freezing (a little). Night temps in low teens maybe single digits and some wind.
Drained a 30 pounder in about 2.5 days, aka, middle of the third night.
At night, the furnace ran almost constantly.
I agree, seems like a consumption issue. But I don't know much about 'em.

2016 Ram 2500, EFIlive tuned, 5” turbo back, 6" lift on 37s
2017 Heartland Torque T29


Portland, OR

Senior Member

Joined: 07/06/2012

View Profile

Good Sam RV Club Member

Posted: 03/29/22 04:46pm Link  |  Quote  |  Print  |  Notify Moderator

Well our experience when we lost power last year for nine days. We averaged about 2.5 days on a 30# cylinder. That was nights in the 30’s days 50’s heating to 68 degrees daytime and 65 at night.

Russ & Paula the Beagle Belle.
2016 Ram Laramie 3500 Aisin DRW 4X4 Long bed.
2005 Copper Canyon 293 FWSLS, 32' GVWR 12,360#

"Visit and Enjoy Oregon State Parks"



Senior Member

Joined: 05/12/2010

View Profile

Good Sam RV Club Member

Posted: 03/29/22 05:17pm Link  |  Quote  |  Print  |  Notify Moderator

The OP's profile shows a 36' Forest River Sandpiper with 3 slides. That should be considered more of a 3 season RV and it is not surprising that it is going to use lots of propane with night time temps dropping to 30 degrees.

The furnace for that unit is 35000 BTU so it will burn through about 0.4 gallons of propane per hour. A 30# tank is typically filled to about 7 gallons giving roughly 17.5 hours of burn time. That is about 70% operation. That is probably about what it is going to take to keep that RV at 65 degrees. I would not be surprised if the furnace is running almost constantly at night.

Maybe the burner is a bit out of adjustment or you have a heat leak but the propane use is not way off of expected.

There is a simple solution. Turn the heat off at night. For temps down to freezing I can get by with little propane and little electric use for the blower. At night I turn the heat off entirely. I have some really good fleece blankets which keep me plenty warm. In the morning the RV temps are likely to be only about 10 degrees or so warmer than outside. Maybe 40-45 degrees. I put the heat on and the RV warms up pretty quickly. Then I turn it off while I am out for the day. So I am heating for an hour or so in the morning and maybe 3 hours of so in the evening.

Don't forget about propane used for hot water. It takes a lot of heat to warm up ice cold water. The typical RV water heater will pull up to about 10,000 btu when running.

You might also want to check on the fill level of the tanks. Places that have a flat charge for filling or which do exchanges often substantially underfill tanks.


Coast to Coast


Joined: 01/26/2004

View Profile

Good Sam RV Club Member

Posted: 03/29/22 05:54pm Link  |  Quote  |  Print  |  Notify Moderator


1 - Most RV ducting is put together badly, so you end up heating your cargo bays more than you heat your coach. This is good for keeping your tanks from freezing but bad for LP efficiency. Walk around in the middle of the night barefoot and see if the floor is toasty. If it is, then you need to get inside the bays and check as much of the ducting as you can get to and find any fittings that are disconnected or even holes in the duct.

2 - 65° is pretty high if you want to conserve your LP and don't want to run your batteries down. Try something closer to 55-58° and throw on some extra blankets.

3 - We use portable buddy heaters in our bedrooms to keep those rooms warm without warming the whole coach. If you keep the doors open, you shouldn't have to worry about C0 since there's so many cubic feet of oxygen in the coach.

4 - Walk around your coach and feel the window sills etc. and feel for leaks to make sure you don't have heat escaping from a window that doesn't shut completely. Our toy hauler has a small crack where the ramp seals against the frame and it can get cold back there since it's so far from the thermostat and it's at the far end of the ducting.

I would be surprised if it's a propane leak, because that much LP would go kaboom if it were pooling someplace inside. My guess would be that it's just running too much and never shutting off.

2014 RAM 3500 Diesel 4x4 Dually long bed. AISIN trans & 4.10 rear. B&W RVK3600 hitch • 2015 Crossroads Elevation Homestead Toy Hauler ("The Taj Mahauler") • Hooligan #3

  • 18 Can Am Maverick x3
  • 05 Yamaha WR450
  • 07 Honda CRF250X
  • 05 Honda CRF230
  • 06 Honda CRF230


Carrolton, Texas

Senior Member

Joined: 06/11/2007

View Profile

Posted: 03/29/22 06:14pm Link  |  Quote  |  Print  |  Notify Moderator

The furnace CANNOT use excess LP. If you went thru 20 gallons of LP in 3 or 4 days, you must have a massive leak by the tanks, which you should hear or smell. Until you figure it out, I would get the tanks refilled and observe HOW MANY gallons of LP are actually in the tanks. If the furnace used excess LP(Impossible) you would have black soot all over the exterior vent. I have 43 years as a RV tech and NEVER have I had a LP appliance use EXCESS LP. Doug
How long will a 20lb propane tank last on a 30000 BTU heater?
14.34 hours-----20 hours on a 30 lb
A pound of propane has 21,591 btu. So if you had a 21,500 btu heater it would run basically 20 hours on a true 20lb bottle. With a 30,000 btu heater you multiply 21,500x20(pounds)=430,000 and divide by your heater size of 30,000btu. Which gives you 14.34 hours if you run it at full all the time.

C Schomer

Pueblo West, Co.

Senior Member

Joined: 12/26/2000

View Profile

Posted: 03/29/22 07:39pm Link  |  Quote  |  Print  |  Notify Moderator

These little safety vent furnaces are extremely Inefficient. I guesstimate the overall efficiency, combustion efficiency along with the stack loss factor, to be about 40%. I got tired of listening to mine cycle below my bedroom slide window and I got a Mr. heater big buddy a couple of years ago. My wifey has fibromyalgia and cold is murder on her. Now I can heat the trailer warmer than I did with the furnace and go a little over twice as long on a 30 pound cylinder.


Regina, SK, Canada

Senior Member

Joined: 12/18/2004

View Profile

Posted: 03/29/22 10:05pm Link  |  Quote  |  Print  |  Notify Moderator


Thanks for the nice formula and the math.

His furnace is 35,000 btu so the 20 pound bottle is around 12 hours.

Regards, Don
My ride is a 28 foot Class C, 256 watts solar, 556 amp-hours of Telcom jars, 3000 watt Magnum hybrid inverter, Sola Basic Autoformer, Microair Easy Start.


No paticular place.

Senior Member

Joined: 08/19/2009

View Profile

Good Sam RV Club Member

Posted: 03/30/22 07:16am Link  |  Quote  |  Print  |  Notify Moderator

jdc1 wrote:

Average RV heater uses about 1/3 gallon of fuel an hour. 30* weather? More than that. A 30 pound tank is 7 gallons. Expect only 14 hours out of a tank in those conditions.

We had our 28ft 5er in -5F and only went thru a 30lb tank per day. The furnace was running 24/7 (well actually we left around day 3 when the roads were clear).

Does the furnace run continuously at night or does it cycle? At 30F, I would expect it to cycle on and off and you should get much more duration than 7-10hrs out of a tank.

I'm betting on a leak. If the propane doesn't run out unless the furnace is on, check for a leak in the feed to the furnace.

Tammy & Mike
Ford F250 V10
2021 Gray Wolf
Gemini Catamaran 34'
Full Time spliting time between boat and RV

Reply to Topic  |  Subscribe  |  Print Topic  |  Post New Topic  | 
Page of 6  
Prev  |  Next

Open Roads Forum  >  Tech Issues

 > Furnace using too much propane
Search:   Advanced Search

Search only in Tech Issues

New posts No new posts
Closed, new posts Closed, no new posts
Moved, new posts Moved, no new posts

Adjust text size:

© 2022 CWI, Inc. © 2022 Good Sam Enterprises, LLC. All Rights Reserved.