Furnaces. Very inefficient!

westend wrote:
For one thing, it seems like those RV furnaces draw combustion air from the surrounding space. If that space is open to the inside of the RV, cabin air is drawn out through the stack and replacement air comes in from somewhere.

Both Atwood and Suburban RV furnaces draw their combustion air from outside of the vehicle as well as exhausting it outside. Internal air is drawn thru a cold air return for the heat exchanger and sent back out the heat registers, just like most residential hot air furnaces.

MEXICOWANDERER wrote:
One RV designer working for the manufacturer. Sitting behind him are four cheapskates with adding machines. Prime Directive. "Make It Cheap! Make It Pretty! Make It Cheaper!"

Isn't this also the mantra of the Great American Consumer?

The long running before and after is safety measure to vent potential gas residue.
On boats with inboard engine, you have blowers that are recommended to run for like 15-20 minutes before engine start, so don't complain about 2 minutes ;)

Is there an adjustment on the cool down after the flame goes out? Mine heats ok, but seems to run along time after the flame goes out and blows cold air!

Propex makes a quiet 9,553 BTU furnace that is 90 percent efficient, and uses 1.9 amps and 8 ounces of propane per hour when running. It draws combustion air from, and vents exhaust to, the outside. I think one could replace my Suburban 16,000 BTU furnace, and a couple or more of them could be implemented in larger RVs.

Too much noise and fuel down the drain. We use a Mr. Heater and an electric blanket on battery and solar. Works great and we can stay anywhere. Mr. Heater needs no electric. Best way to go.

For one thing, it seems like those RV furnaces draw combustion air from the surrounding space. If that space is open to the inside of the RV, cabin air is drawn out through the stack and replacement air comes in from somewhere.

Also, yeah, the holes, I've seen some bad pictures on this Forum, half the under shower area open to just run two supply lines and a drain.

My furnace is a tin can with a gas ring (Sportsmen brand heater). It is very efficient, usually just idling along even in real cold temps.

Thanks gentlemen for all the great responses. I guess I can always turn on the furnace in our new to us 09 Cedar Creek go outside and roast my wieners at the furnace chiminy. Should only take a few minutes.

One RV designer working for the manufacturer. Sitting behind him are four cheapskates with adding machines. Prime Directive. "Make It Cheap! Make It Pretty! Make It Cheaper!"

One can of aerosol foam insulation may turn out to be the best money you've spent in a long, long, time. I spent four hours insulating behind the absorbsion tubing on the last Norcrap refrigerator. It and an inch of rigid foam board everywhere else reduced interior temps from the high fifties at max cold setting to the high forties at "7". Problem turned out that Mexico summer temperatures allowed food to spoil. Something that has not happened for eight years using a freon unit.

But for sealing up cracks, holes, and unintentional wind tunnels, foam is unbeatable.

Not only furnace is having low efficiency, but check the construction of your RV.
On my camper I discover that power cable compartment is "cold" one with hole for the cable and non-insulated door. But the compartment had no divider from the space under bathroom sink, where another opening lead to tank compartment with another open connection to the outside.
Such design not only radiate lot of heat, but in case of furnace heating - create chimney effect that runs cold air under shower pan and bathroom vanity.
I used big can of "Great stuff" foam to seal some of those passages and figured out that in case I will camp on snow - stuffing sponges into cable compartment can save me quite a bit of energy.
Than would I have sewer hookup - I don't need to run heat to tanks compartments. New installed gate valve on ducting will allow me to make the choice.