Rv furnaces?

[ahh_me2]

A few weeks ago I ran into a fellow I know, and saw a Suburban RV furnace intake/exhaust outlet plate on his mini van.
Now I remembered a few years back him showing me the aftermarket conversion of his vehicle but I had never paid attention to his method of heating the interior.
He doesn't live in this van, it's more for camping or longer road trips, and it is really small, with some kind of pop-up roof with fabric walls.
I can't remember what make/model of vehicle but I will probably see him again in a couple weeks, and if I do, I'll take some pics.

Anyway, after I noticed his heat system, I asked if he could show me the heater. He opened the rear hatch, lifted a carpet covered plywood lid and lo and behold, a small Suburban furnace with ducting!

I hadn't realized just how small these units were, and never thought they could be put into such a small vehicle, so it got me thinking...

I was having some issues with the layout and emplacement of the heater that I was looking at using in my build, and figured this type of heater would solve most of my problems, so I bought one.

Here I am bench testing the electrical/blower assy, and also checking the current draw. It is supposed to use 2.7amps, but my meter shows it around 1.8 amps with a slight surge on power-up.




So I guess I'm wondering why more vandwellers don't use this type of furnace as it seems like a much better system over the various buddy heaters/catalytics etc.

Any thoughts?

 

[TMG51]

I'm curious what type of answers you'll get to this. I have one of these heaters installed in my van, but I've never turned it on. I've inferred from context that people seem to think they waste propane / battery power so I've just kind of ignored it for now. If it's true that they're wasteful I'll probably remove it for space savings eventually. But if it's a viable option I'll keep it.

I'd like to hear what other people think about these RV furnaces vs Little Buddy heaters etc.

 

[Almost There]

For me the cost of the furnace, the cost of installing and plumbing below level propane tanks, outfitting the cargo van with an access panel for filling the tank and the venting required of the RV style propane furnace just isn't worth it for the amount of use I would ever get out of it. All of these are beyond my skill level and would have to be done by several different professionals or at an RV centre. My cost here in Canada, probably in excess of 2Gs.

A portable heater with a portable tank for those few times that I will need to warm the interior is sufficient. I can also take that portable tank and use if for the barbecue or the propane stove.

It's also a cosmetic thing - I hate having the side of my nice white van carved up with access and vent panels..

TMG - if you've already got it on board then it makes sense to use it.

 

[compassrose]

The vintage (1980's) Suburban in the Class C is pretty decent on LP. I've heard the newer ones aren't as good but I don't have any experience. RV stuff does not have to be energystar compliant.

The furnaces come in various sizes. You might want to look at the ones they are putting into popup campers. They do tend to have a much smaller footprint.

I suspect that many furnaces are poorly ducted and are possibly undersized.

I heat with electric space heaters when on sufficient shore power and with LP fireplace and LP wall mounted Tag-a-long heater when not.

 

[ahh_me2]

I'm curious what type of answers you'll get to this. I have one of these heaters installed in my van, but I've never turned it on. I've inferred from context that people seem to think they waste propane / battery power so I've just kind of ignored it for now. If it's true that they're wasteful I'll probably remove it for space savings eventually. But if it's a viable option I'll keep it.

Interesting...
I have a Suburban range top stove with 3 burners, front burner is 9000 btu and the 2 back burners are 7000 btu's each
The furnace I just purchased is 16,000 btu's so it would be the equivalent of running my front burner and rear burner on the stove.
Now i have done a lot of cooking on that stove and the propane usage seems to be quite small as I haven't filled the 20#er in quite a while.

As for power, even at the rated 2.7 amp draw, if the furnace cycled 30% of the time we would have :
(24 hres X 2.7 amps)X 0.3 = 19.44 amps in a 24 hour period.

Now I did pick random cycle times... outside temps, amount of insulation in vehicle etc, all would contribute to a higher or lower cycle time.

Not trying to convince you or anyone else, just kinda thinking out loud.

 

[ahh_me2]

For me the cost of the furnace, the cost of installing and plumbing below level propane tanks, outfitting the cargo van with an access panel for filling the tank and the venting required of the RV style propane furnace just isn't worth it for the amount of use I would ever get out of it. All of these are beyond my skill level and would have to be done by several different professionals or at an RV centre. My cost here in Canada, probably in excess of 2Gs.

A portable heater with a portable tank for those few times that I will need to warm the interior is sufficient. I can also take that portable tank and use if for the barbecue or the propane stove.

It's also a cosmetic thing - I hate having the side of my nice white van carved up with access and vent panels..

TMG - if you've already got it on board then it makes sense to use it.

I understand what you're saying AT, as I used to think that also.
However, the only access or vent panel needed is the small 4" X 8" intake/exhaust plate.
I will be running off of a 100# tank, but it can be easily run off a 20 pounder.
I have a regulator with about 4 feet of hose that I use on my range stove that I am going to grab later on
and hook it up to this furnace to bench test.
Now a person does need to provide a short 3/8 flared copper connection to connect to the propane hose.

Again, just thinking out loud, but I'll post a pic or 2 when I get it setup on the bench tonite or tomorrow.

 

[Willy]

I have the older style non-electric vented furnace and find it to be preferable over the new (electric valve body+fan) units. One of the problems with the new(er) style units is that, if the pilot flame blows out, the furnace will still turn on, fan blowing, but all it's doing is moving cold air around and will do so NON_STOP!! That can lead to a severely depleted battery in the morn and an EXTREMELY cold living area, since the furnace then effectively acts like a heat exchanger and sucks it all out. The same thing happens if you run out of propane with the furnace turned on.

What I did is to add a thermocouple (normally open) to mine with a computer fan hooked up to it. Thus, when the burn chamber reaches a certain temp, the thermocouple closes and the fan turns on, blowing air past the burn chamber and also increasing efficiency. ..Willy.

 

[ahh_me2]

I have the older style non-electric vented furnace and find it to be preferable over the new (electric valve body+fan) units. One of the problems with the new(er) style units is that, if the pilot flame blows out, the furnace will still turn on, fan blowing, but all it's doing is moving cold air around and will do so NON_STOP!! That can lead to a severely depleted battery in the morn and an EXTREMELY cold living area, since the furnace then effectively acts like a heat exchanger and sucks it all out. The same thing happens if you run out of propane with the furnace turned on.

What I did is to add a thermocouple (normally open) to mine with a computer fan hooked up to it. Thus, when the burn chamber reaches a certain temp, the thermocouple closes and the fan turns on, blowing air past the burn chamber and also increasing efficiency. ..Willy.

Yeah, I wanted a gravity style furnace but they don't make them anymore apparently.
Also they now use spark ignition, and so after 1-3 attempts and failing, they shut down and won't run the blower fan.

 

[Willy]

I picked up a used 'gravity fed' one a coupla weeks ago for $35, and it's now installed in my rig. It's good to see that the manufacturers have changed how their furnaces operate.. tho not as thrifty power-wise as my setup. NYAA Nyaa! ..Willy.

 

[ZoNiE]

I have one in my travel trailer. Loud as hell. Wakes me up. If you are a light sleeper, make sure your duct runs are long, and the intake is far away from your head.

I found an ALDE Boiler/recirc unit very cheap on ebay and will be installing it this fall. ALDE's are usually very expensive, but I'll be into this for less than $400 with all the plumbing.

 

[rvwandering]

I think that we're pretty heavy energy users. We have a 22 gallon propane tank (about 100#) and fill it about once a month in the winter, about every 1 1/2 months the rest of the year. We use the range every day, often two burners at once and have a Dometic fridge running exclusively on propane and a propane water heater. Our furnace is an Atwood RV furnace and it's a little too big for our RV. We can only leave it on for a short time before it gets too hot and we always turn it off at night.

So anyway it's not the propane but the electric that the furnace blower uses that makes them impractical. The furnace uses more energy than everything else - lights, TV, computers,etc. - combined. If we have to use it a lot, our solar panels can not bring our batteries up to full charge and we have to drive or plug in after two days.

 

[westriver]

So anyway it's not the propane but the electric that the furnace blower uses that makes them impractical. The furnace uses more energy than everything else - lights, TV, computers,etc. - combined. If we have to use it a lot, our solar panels can not bring our batteries up to full charge and we have to drive or plug in after two days.

This is the biggest problem. I have awoke to ice cold travel trailers on more than a few occasions, only to find that the blower killed the battery in the middle of the night. With a trailer it's as easy as running the tow vehicle to give the dead trailer battery a bit of juice, but you would need a separate "house" battery in the van to protect yourself from being cold, with a dead starting battery. Given the rave reports I have always seen regarding the little buddy heaters, I can't imagine going through all the effort to install an RV furnace in a van.

 

[B and C]

I have a Suburban 16,000 BTU unit in the Roadtrek.  It is the one that tries to light 3 times before giving up.  It is noisy though, but I wouldn't be without it.  It cycles infrequently during use and doesn't run very long except when first turned on.  I run out of black holding tank capacity way before I need propane.  The thermostat is by the bed and remains set at a comfortable level.  Before going to sleep, I turn it off with a switch on the thermostat.  If we wake up cold in the middle of the night, we just pull up the covers.  When I wake in the morning, I turn it on.  I do not have to worry about leaving a window open for oxygen and the water vapor (and heat) to escape if using something like a Little Buddy.  The heater is at floor level in the middle of the van and keeps our feet warm as well as the rest of us.  If the propane has been turned off for a few days, it will not light, the Dometic fridge will not light and the water heater will not light (air in the system).  I have started turning on the cooktop right after I open the valve on the tank and get it lit.  After the stovetop is lit the first time, everything else works as it should.  Propane is heavier than air.

I do have a propane detector, carbon monoxide detector and a smoke alarm.

 

[Spaceman Spiff]

Having used both (furnace and catalytic heater) in pop-up truck campers; my 2¢:

• Furnace (~70%) is less efficient than cat heater (~99%)
• Furnace can be controlled by thermostat (will hold a set temp), cat heater must be manually regulated
• Furnace does not add humidity to inside air, cat heater adds about 1 pint per 10,000 BTU per hour
• Furnace uses battery power (ignition, control board, fan), cat heater does not
• Furnace fan can be noisy, cat heater is quiet
• Furnace does not have very hot elements exposed, cat heater's heating element is touchable (children, pets, spiff)
• Furnace must be installed with plumbing and fuel tank, cat heater can be totally portable
• Furnace is installed with heat shields, cat heater needs to be set up away from flammables
• Since the flame is using outside air a furnace is safer to run while sleeping, cat heater must be vented
• Furnace is not damaged by dust, cat heater is (must be covered when not in use)
• Can't accidentally tip over a furnace (unless you tip over your truck )
• Both have altitude shutoff controls (varies by make, model, phase of moon, ... )

I have a Mr Buddy 4,000 - 9,000 BTU heater for my pop-up camper.  Works well in all but the coldest weather (but I am a Minnesotan, 40° is tee shirt weather  ).  I live alone with a beagle and he is smart enough to give it wide berth; me not so much :s .

I'll probably think of more after I hit send, but this is enough for now.

-- Spiff

 

[akrvbob]

I'd never even consider a furnace!

1) Too much battery draw when you can least afford it.
2) Way to complicated for me to install safely=BIG BUCKS
3) In the tiny space of a van the furnace bakes it out, then you turn it off and get cold.
4) Too noisy.

Their only advantage is they are vented, but to me that is just not worth all their other negatives.

Personally, I just use my Coleman propane stove for heat and it works extremely well for me. If it's too cold for that I add the smallest Mr Buddy, the 3800 btu one.

* Less than $100 bucks total.
* Takes almost no room.
* Silent.
* No electric usage

Bob

 

[TMG51]

I'd never even consider a furnace!

1) Too much battery draw when you can least afford it.
2) Way to complicated for me to install safely=BIG BUCKS
3) In the tiny space of a van the furnace bakes it out, then you turn it off and get cold.
4) Too noisy.

Their only advantage is they are vented, but to me that is just not worth all their other negatives.

Personally, I just use my Coleman propane stove for heat and it works extremely well for me. If it's too cold for that I add the smallest Mr Buddy, the 3800 btu one.

* Less than $100 bucks total.
* Takes almost no room.
* Silent.
* No electric usage

Bob

All this talk of using stoves to heat with instead of heaters has gotten me thinking... I've refrained from firing up my furnace for the reasons you've described, but now I wonder about using my little propane grill to heat with. I could put it on the floor near my sitting area instead of the stove top which is in the kitchen. The downside would be if there's food/grease left in the grill it's going to get smoky fast.

I once had an apartment where the propane ran out one week before Christmas. The gas company would not deliver for two weeks. I had an electric range, and for two weeks I heated a two-story apartment by boiling water. The water vapor distributed heat well. The downside was that it rained indoors and everything paper turned to mush.

 

[karl]

Thirsty has an Attwood 12,000 btu, specs say draws 1.8.
Still pack a mr Buddy that I used for years.

The main reasons I spent the ridiculous money for it was to save my dogs tail- burning hair and yelping bust my joy, hers too. She can't seem to control that happy wand.
I really appreciate the dry heat, not so much the noise
It's nice to come back to a warm van in winter.

 

[SoulRaven]

I have the older style non-electric vented furnace and find it to be preferable over the new (electric valve body+fan) units. One of the problems with the new(er) style units is that, if the pilot flame blows out, the furnace will still turn on, fan blowing, but all it's doing is moving cold air around and will do so NON_STOP!! That can lead to a severely depleted battery in the morn and an EXTREMELY cold living area, since the furnace then effectively acts like a heat exchanger and sucks it all out. The same thing happens if you run out of propane with the furnace turned on.

What I did is to add a thermocouple (normally open) to mine with a computer fan hooked up to it. Thus, when the burn chamber reaches a certain temp, the thermocouple closes and the fan turns on, blowing air past the burn chamber and also increasing efficiency. ..Willy.

We were in pretty cold temps in NC, full-time in a travel trailer and we experienced a few times when because of the cold, the furnace just pooped out and we had the cold air blowing, endlessly, but were hooked up to electrical at the time.  This was a brand new trailer so it wasn't just a worn out furnace.  In the ice storm, it was less than a delightful winter, the owner of the park let us all take turns recharging our batteries when the power went out on a generator that he had.  But, the furnace blower is a power hog when it comes to the battery.  Also, those furnaces can be so noisey and ours woke me every time it kicked on.  

I am really looking for things like A/C not on the roof, just one that can be replaced at Wal-Mart and same with heater, just buy a new one locally that I could handle myself rather than paying someone else or buying parts that cost almost as much as a new unit.

 

[ahh_me2]

Well, some interesting and varied comments, I was kind of surprised in some ways.

I've lived for the past 16 years with my bedroom right next to the furnace room with a super loud furnace, so I find this Suburban
pleasantly quiet in comparison!

While I am looking to put this furnace in my cube van build, had I actually taken a closer look at the Suburban last year, I would have put
it in my Ford van right from the beginning.

I suppose for extended boon-docking one does need an adequate power source such as good solar and batteries, but I am urban docking with access to shore power on average 12 hours a day, so I don't expect it to draw that much from my house batteries.

While some have mentioned the difficulty in hooking it up, it can be very easily hooked up using a Mr Heater 11" WC regulator and hose assembly that I paid $30 for.



While technically not the correct way to connect as on the hose itself is a warning not to be used inside, it is relatively easy to get a length of 3/8 soft copper made up with flare fittings on the end to route it to the outside of the vehicle, and then connect the Mr Heater hose/regulator.

I too was concerned about large access doors or unsightly vents but this unit has a very small intake/exhaust port, basically need to drill 2 holes
for the tubes.



Any way, thanks for all the replies! It was enlightening!
And as usual, there is no right or wrong way, whatever works for each and everyone of us in our own unique situations/environment!

 

[compassrose]

I suppose for extended boon-docking one does need an adequate power source such as good solar and batteries, but I am urban docking with access to shore power on average 12 hours a day, so I don't expect it to draw that much from my house batteries.

I don't boondock nor do I have an RV furnace so I couldn't care less BUT boondockers report that it depletes the battery bank overnight.