Furnaces. Very inefficient!

I love it "What's The Point?"

PROPANE PLANT > 73 Miles

Dutchman Sport has the best option IMHO. An extra inch of insulation and GOOD twin pane windows would do wonders, cold or hot.

Of course my Olympian 8000 has an inch of dust on it. And it's stored where a falling 20 lb coconut can't bean it. I purchased 45KG of gas, let's see, April 2015.

There's solely one good thing about suffering aches, pains, heart, vision and hearing problems of old age. Hook Up & Haul. Make like a goose. Go where the weather isn't. Snow? I get to see it online. Shorts & Tee Shirt. Sandals (huaraches).

For the smart folks, there's guaranteed good weather in your future...

Your right. RV furnaces gobble propane, drain the battery, are noisy, and often have uncomfortable swings between being too hot and too cold.
But rather than fighting it, why not just install a radiant heater? Much more comfortable, no (or minimal) electric use (depending on the type), quiet, and much more comfortable. The Wave (4,6, or 8) series of heaters are one example, but there are others.

I too am very happy with our furnace, for several reasons. First of all it is large enough to get the job done.... and then some. Our 24" Nexus Phantom 23P Class C came with a 35,000 BTU - 4 duct furnace. I don't think we have ever had it run for than about 10 to 15 minutes before it was well over 72 degrees throughout the coach.

Another factor for us is how well the Nexus is built/insulated. Once you get it warm it stays that way for quite a while. When camping with sub 30 degree temps leaving the thermostat set at 65 when we go to bed generates about 5 minutes of run time once or twice a night. It's nice to have the thermostat right above my head on the wall where I can reach it while still snug under the covers to toast up the coach in the morning before getting out of bed. :B

Also there are a couple of proactive steps you can take to increase your furnace's efficiency. Hang a curtain or better yet a heavy blanket/quilt between the cab (of a Class C), and the living space of your coach. A windshield cover will also keep the cold out - heat in. Pulling your window shades or using Reflectix (or similar insulation), will also help.

:C

The noise and efficiency issues don't bug me much. These are built to a size and price point and seem to do well with that. I simply do not have room for a larger quieter more efficient furnace.

I'm actually quite happy with the furnace. I take winter dry camping trips and encounter low 20 degree temps. Furnace never failed to keep me comfortable. If there is incremental improvement in the furnaces-I'd prefer it to be in the noise area. I'm best in RVs where the sleeping area and the furnace are well separated.

they make a 2 stage furnace that would go a long way toward better efficiency. Small burn for a longer time so less cyclying. BUT, it's all about COST. Can you make it cheaper? They could make a high eff furnace but think cost and how many people would buy it. A lot of you said you don"t use the furnace. I use electric whenever possible. So we are not a good candidate for a high eff furnace.

My complaint with RV furnaces is that the burner doesn't turn on soon enough and stays on too long leading to uneven heat. Electric space heater is much better down to around 35 or so.

It's not just the efficiency of the furnace itself that's an issue.

Many RVs nowadays have an enclosed underbelly and the furnace pumps some of the furnace output into the underbelly cavity to prevent the tanks and piping from freezing and to make the floor feel warmer. As a result, some of the heat ends up going into the great outdoors through cracks and gaps instead of being recirculated. Very inefficient design.

Secondly, the ducting is partly to blame. The flexible duct (2" & 4") they use creates friction loss. Sometimes they stuff lots of unnecessary extra duct in the runs rather than trim it and to keep bends to a minimum. As well, if a duct goes into the underbelly space and comes back up into a heated area, the duct won't be insulated and it may be sitting on top of the coroplast with no insulation.

Thirdly, the way they install the duct in some locations can cause it to become partially collapsed and thus restricting air flow.

Lastly, you may have large openings whacked into the floor for ducting & pipes. Ours had a large opening right next to the furnace and some return air was being drawn into the furnace from cold outdoor air.

Our furnace struggled to keep our TT sufficiently warm in temps around 40F and below and took forever to warm the interior up. Dealer claimed it was a faulty sail switch, but that was not the case at all. Our trailer has a 4" duct that goes into the underbelly space and back up to an outlet in the kitchen. I pulled it out and insulated it and used semi-rigid aluminum duct. I also increased the duct to the bedroom from 2" to 4". HUGE, HUGE improvement! Full story and pics here on another thread from a few days back. under-performing furnace

Last year I installed 3 permanent recessed electric heaters totally 1750 watts along with a demand controller I built that shuts the heat off when an high demand appliance gets plugged so our 30 amp breaker won't trip. Didn't have to use our furnace once last season. There may be times though that we could end up dry camping and still need the furnace.

They are very inefficient. But one way to beat it,....don't use it.
I never use mine,....most all my heat is done w/ 2 Olycats.
And if I need a little more, I fire up the cooktop before I fire up the furnace.
And it isn't money,......its the hassle of finding propane, that is "needed" for much more efficient uses.

The problem isn't efficiency so much as practicality.

An RV of any flavour is a relatively small space, that means you're never going to be far from the furnace. So noise will be a consideration.

But more importantly electrical power demand while off-grid.

To achieve higher efficiency would require a much longer burn at lower BTU rates and a power venting motor to push the heated air through the more complex heat exchanger. So now you have 2 blowers running (albeit one much smaller) and running for much longer periods.

Furnaces are already big power hogs, I couldn't imagine the extra battery capacity you would need to go this route.

ivbinconned wrote:
Seems to me that the furnaces in rv's are patheticly inefficient. There are natural gas house furnaces that are so good that the exhausts are plastic!

You have to realize, it's an RV, not a stick and brick house. Owning and operating an RV isn't exactly the most efficient use of money either, but it sure is enjoyable.