Catalytic Heaters

[Art Davis]

I have found one thread that discusses these gadgets, but it didn't really answer some questions I had about them. I just read an article about them that was pretty good---but still didn't answer the questions I had. Maybe you guys can help.

I have problems sleeping if there is any noise at all around me, so the standard furnace in my rig often wakes me up. I have looked for a small electric cube, but the fans in those things seem pretty noisy.

I had thought a catalytic heater might be the answer. As I understand things, there is no danger of fire because the temperature of the catalytic element is below the flash point of propane. And I understand that they are quiet because they put out radiant, rather than convection, heat.

I am not sure what the BTU rating of my standard furnace is, but I suspect that a catalytic would be sufficient for our needs.

Here are my questions:

1. Are they REALLY all that safe? Is there any real danger from asphysixiation from lack of oxygen if I maintain some type of small opening? And how much ventilation is needed?

2. Do they REALLY not give off products of incomplete combustion? In other words, do they actually not need to be vented (because of this issue, not for the sake of sufficient air to breath)?

3. How efficient are they in terms of propane? They would certainly save on the battery because they apprently have no blower to move the air around. (Am I right about this?)

4. If they are all that great, why don't trailer manufacturers offer them as standard equipment?

Thanks for any insight you can provide. If I have overlooked any threads that already discuss these issues, please tell me.

Art

P.S. By the way, why will my browser "back" button no longer work on this site after its recent refurbishment?

[Gina D.]

HERE is a recent discussion on them.

Your questions are many and typical of anyone considering them.

They give off a slight "Hiss" when on, nothing more than the fan of your laptop might produce, so noise is a non issue.

They will give off byprodcut when they are older and the pad is spent and not burning as efficiently as they do when new. This takes decades to happen tho. I replaced one in my 13 for that.

You will need open windows, yes, they consume oxygen and you are in more danger of suffocating than being poisoned by gas.

The portables consume about a canister of propane a nite when run on high, I run mine on low during the day and can get a couple days out of a standard canister. I rarely run them at nite.

My 13 had a wave 3 installed, and I did not notice any gross consumption with it. I intend to install one in my 17 eventually.

[Brian B-P]

I can guess at two reasons that unvented, radiant, catalytic heaters might not be widely offered by travel trailer manufacturers:

1. they may not meet some regulations for RVs
2. they may not be sufficiently effective, due to inadequate distribution of heat

Most RV manufacturers build a range of sizes, including units with multiple rooms which could not possibly be effectively heated by a single radiant unit. They would need forced-air furnaces (or circulating hot water systems) for most of their lineup, so they would not likely offer a different type for their one smallest model. The makers of our "eggs" tend to specialize in our small trailer, so this would not apply to them, and I'm back to my basic guesses above.

If anyone knows what the CSA or RVIA standards say about unvented heaters in travel trailers, it would be interesting to hear.

[peterh]

Catalytic heaters use a unique property of metallic platinum to grab onto the propane molecule and hold it in exactly the right position for oxygen molecules to come cruising along and attach themselves to the carbons and hydrogens. Getting the propane lined up in this precise manner lowers the amount of heat energy that's required to bounce the propane molecule around enough for it to randomly run into oxygen molecules when bent and twisted at just exactly the right angle for the oxygen to glom on to the propane.

(Technically, the platinum grabs the propane's eight hydrogen atoms, exposing the three carbon atoms and making them available for oxidation, leaving the hydrogens, which are pulled off the platinum by other oxygens.)

Because the platinum grabs on to the propane and won't let go until it's completely burned away, making carbon dioxide (CO2) and water vapor (H2O), the only by-products of the reaction are CO2, H2O, and heat. The platinum itself isn't change in any way, so it's ready to repeat the process over and over again. This is exactly the same thing the catalytic converter on your car does, except it grabs on to partially burned hydrocarbons and makes sure they're fully burned off before leaving the exhaust pipe.

The only way a catalytic heater can release carbon monoxide or any other chemicals is if the propane valve is opened too wide (catalytic heaters are designed so this shouldn't ever happen), in which case raw propane enters your trailer, or the platinum plating on the catalytic element flakes off or becomes contaminated by other metals, making it less efficient. (That's why cars with catalytic converters can't burn leaded gasoline; the lead contaminates the platinum catalyst.) Gina has already commented that a catalytic element can last for many years before contamination becomes a problem.

So, what does this mean for a small RV? You'll need a fresh air inlet so you don't deplete the oxygen in your trailer, and you'll want to leave a ceiling vent cracked open so the water vapor can escape and not condense all over your windows and other surfaces. I, personally, would also install a propane gas detector (a wise precaution in any case) and a carbon monoxide detector (more for peace of mind than anything else).

Some downsides to a catalytic setup are: They don't have a fan to circulate the heat around your trailer, so heating will be uneven. The water vapor the catalytic heaters give off puts humidity in the air and can condense on cold surfaces in your trailer. And, finally, most catalytic heaters have just three settings, off, low, and high, and no thermostat so you can't set your heater to keep your trailer at, say, sixty-four degrees (18c) at night and seventy-two (22c) in the day.

On the plus side: Pound-for-pound of propane, they are very efficient; you'll get the absolute maximum heat possible for every pound of propane you burn. Most units don't use electricity, so it's ideal for boondocking setups. And, they are very quiet.

--Peter

[Jan Adams]

We have a 78 VW Westfalia - and we have two catalytic heaters. One that uses Coleman fuel and one that uses propane. We love them because they make no noise. The one that uses Coleman fuel will last the whole night and part of the next with no refill. The one that uses propane will last until the early morning, when it is the coldest. So, if it is REALLY cold, we use the Coleman fuel one.

We also crack open a window and have never had any problems with them. They heated the Westfalia sometimes to the point of having to open the window even wider - nice problem to have - much better than no heat!

[Kevin A]

We have a new Wave3 in our 16' UHaul that heats very well. My question concerns fire from other objects igniting. I won't run the heater at night because it is near enough to the bed to have the possibility that a stray blanket or sheet could come in contact. I assume this will ignite the fabric, right? How far away is safe? Our option thus far has been to run a small electric heater on low at night and only use the Wave3 when we're awake and the bedding is put away.

[Art Davis]

Thanks folks for the insights.

PeterH, that was a great minicourse in catalytic conversion---just what I needed! As an old prof, I really appreciate a good presentation of a difficult topic. Have you ever taught?

Best,

Art

[peterh]

Thanks folks for the insights.

PeterH, that was a great minicourse in catalytic conversion---just what I needed! As an old prof, I really appreciate a good presentation of a difficult topic. Have you ever taught?

Best,

Art

I've done some teaching and tutor college physics students to keep my science skills sharp, but I also write books and magazine articles about computers, communications, and a few other (mostly technical) topics.

--Peter

[Gerry]

We have a new Wave3 in our 16' UHaul that heats very well. My question concerns fire from other objects igniting. I won't run the heater at night because it is near enough to the bed to have the possibility that a stray blanket or sheet could come in contact. I assume this will ignite the fabric, right? How far away is safe? Our option thus far has been to run a small electric heater on low at night and only use the Wave3 when we're awake and the bedding is put away.

I am in a mind of getting one of these units for my 13ft Boler and your concern is just one of mine.
I'll do alot of shopping around before I buy (thats just the way I am) and as of now I have looked at the some portable floor models that take the 1# tanks, the Colman Buddy, with there own regulators (Brother-in-law has one working in his camp and has it hooked up to a seperate gas line to a 20# tank) and looked at some floor models that look real fancy, I'm sure for added heat in homes. a bit too large for the limited floor space in the Lady-Bug.
And, looking into wall mounted vented models mentioned in another discusion:
http://ventedcatheater.com/index.html
Real nervouse about being sick or worse from the CO2 while sleeping and as mentioned above the fire hazard.
Kevin I am sure that if your heater has enough BTU's that you can have it moved far enough away from your bed while sleeping. after all you will be heating the trailer not just the bed.
Even the little electric Cube heater I use will heat the whole trailer so being next to bed is not a problem but in the Boler having a larger unit on the very limited floor space may be a problem so goes the argument for a wall hung unit
Read on one box of a floor model that required fresh is is 6 square inches, am I to assume that if it needs 6 inches in I will need 6 square inches out for exhaust and I will be safe????
Gerry the Canoebuilder

[Alf S.]

Hi: Check out the selection of heaters over at Vintage Trailer Supply Lots of info there. They recommend 1sq. inch of vent for every 1000BTU of heat. My 2.5 cents worth!!!
Alf S. North shore of Lake Erie

[Joe Z]

Gerry.....
I read a very sad article about 2 months back where they had a catalytic heater in a horse trailer with a separate section for sleeping and they had the vent cracked open pretty good up top at the vent and you would think all would be fine.... well it wasn't and sorry to say there was a few fatalities (asphyxiation)and they blamed it to the reasoning that a vent needed to be opened down low and one up top for the air to circulate. with it open up top only was not enough for circulation. if i can find the article i will post it.
Joe

[Gerry]

Yes, I also remember hearing about that, so sad. I always have my over the stove window open while useing stove with back window open for this cross ventilation so I would do the same with a heater.
Even when the furnace in Lady-Bug (when it worked) I felt more comfortabe with some sort of ventilation.
Plan of attack is to first try again to get the Duo-Therm to be reliable but on my own...after paying $300 for what amounted to being for a dealer to vacume out dust and dirt from behind the furnace because it didn't work when it went in and it worked once when I got it home and on the next trip it didn't and hasn't worked since.
That $300 would have almost paid the $470 for that Platinum Cat Heater....
Will have to sell more fire wood to get the bucks.
Will feel much more safe with a wall mount externaly vented model, not to mention the area that a floor model will take up in the 13foot Boler
Gerry the canoebuilder

[Pete Dumbleton]

Hi: Check out the selection of heaters over at Vintage Trailer Supply Lots of info there. They recommend 1sq. inch of vent for every 1000BTU of heat. My 2.5 cents worth!!!
Alf S. North shore of Lake Erie

Coleman recommends ten square inches for the 3,000 BTU Black Cat.

The horse trailer tragedy is the only time I have read of catalytic heater fatalities and IIRC it was a policeman who made the remarks. I personally suspect that something else was wrong. However, I personally don't sleep with my unvented LP heater on, relying instead on a good sleeping bag. The egg heats up quickly in the morning with the heater back on and making my coffee.

[CarolnJim]

We don't ever use our Buddy Heater while sleeping.

We just purchased two new sleeping bags at Sam's Club that go down to zero degrees. We'll be trying them out next week when we camp at Jalama Beach in California.

It won't get down to zero at night (we hope) probably closer to 35 degrees.. these sleeping bags should keep us comfy. Jim's job is to turn the heater on in the morning... works for me.

[Byron Kinnaman]

We don't ever use our Buddy Heater while sleeping.

We just purchased two new sleeping bags at Sam's Club that go down to zero degrees. We'll be trying them out next week when we camp at Jalama Beach in California.

It won't get down to zero at night (we hope) probably closer to 35 degrees.. these sleeping bags should keep us comfy. Jim's job is to turn the heater on in the morning... works for me.

We have 15 degree sleeping bags. I find them too warm in temperatures above 35 degrees. We have the factory forced air furnace and set the thermostat at 50 at night, and use 50 degree bags. We also keep the window over the stove open a bit, the roof vent open a bit, and the windows on each side open a bit. I'm not sure what I would do without the forced air furnace.

[Joe Z]

I think i would do about the same thing............ Use the catalytic in the day and try to get thru the night with a sleeping bag and/or set the thermostat down real low on the furnace hog when it's really cold. That catalytic is a real nice way to save precious battery amps when possible and the vented catalytic ones may be a different story and get you thru the night....i just don't know enough about them yet.
Joe

[peterh]

OK, for those who are interested, I sat down with my calculator and worked this out:

A single one-pound cylinder of propane (10.3 mols/lb) burned in a catalytic heater will consume all the oxygen present in (roughly) 14 cubic feet of air at sea level (.13 mol o2/liter STP), about the same volume of oxygen consumed by a resting adult over the course of two days.

Assuming an air space of 10' long by 6' wide and 3' tall (as an approximation of the air volume of a 13' trailer), that's about 8% of the total oxygen available in a small trailer, enough to push the O2 level to 19.3%, slightly below the OSHA minimum of 19.5% but well above the 16% o2 concentration where asphyxiation effects occur.

I believe the small Olympic Wave 3 heater set on low burns one pound of propane every eight hours, so it's possible you could make yourself sick by sealing yourself in a 13' trailer with a small catalytic heater set on low all night, but it's not going to kill you. Set on high . . . maybe, but not low. That said, even when set on high, a small fresh air intake to the heater plus a window or vent opened a crack elsewhere in the trailer should more than supply all the oxygen you and the catalytic heater need to keep you warm, happy, and alive.

Thinking back, Gina posted some excellent pics of her catalytic heater and the air intake vent she installed in her old 13' trailer. (And, dare I note, that both Gina and her flying monkeys all seem to be doing quite well.) Perhaps she can dig those pics up and post them again if anyone is curious?

-_peter

--Peter

[Gerry]

Does anybody know of a wall hung model Cat Heater.
As said, one of the problems I have with most floor models is they take up most the floor space in the Lady-Bug.
We do not spend any time in the trailer during the day and would only use the heater at night to keep the trailer a comfy 68 degrees.
Haveing it on during the night and haveing the required vents open I am sure the warmth will be there but that all dreaded mid-night Nature Call I do not want to have to start it out with a half asleep vault of an open flame in the heater.
Jack Sprat I am not....even on my best day due to artificial hip.
Gerry the canoebuilder

[Joe Z]

Peter
I really rely on your post as you really know your stuff with technical Data and i use your info with my common sense (but so so technical brain).........those figures you give really help out for that wave3 which is presently my favorite.
when you say "fresh air to the unit" and another window elsewhere opened do you mean to pump air in from outside and direct it to the front of the unit or just opening windows on each end of the trailer is fine?____
Joe

[Brian B-P]

Does anybody know of a wall hung model Cat Heater.

At least the common models of the Olympian heaters can be wall-mounted.