Heat propagation of catalytic heaters

wrcsixeight · Jan 9, 2013

I have never used a catalytic heater, but my understanding is they do not heat the air so much as heat items in the line of site of the hot plate by radiation, which then heat the air by convection. I am envisioning putting a Coleman Blackcat/sportcat about 1 foot from my roof, aiming down ward at a 30 to 45 degree angle.  Best place for this would be under where my roof vent is, shining on my third chair to heat me and my bed.  It would fit very well here, be very convenient, if it would function properly, and still be safe.   I am wondering how hot the roof would get directly above in this orientation, or if most of the heat would be radiated downward as I would prefer. My roof vent has 2  inline 120mm computer fans and I do not shut them both off completely until it falls below ~50f.  I do not cover the vent until below 45.  I like fresh air, and I do not get cold easily. I am not really fearing the CO build up or oxygen depletion so much as I am worried the unit is not safe to operate pointing downward, or that so much heat rises directly off of it that the roof itself is in danger of melting or worse.  If this needs to be on the floor only aiming upward, then I'll pass on this type of heating, as I've rarely ever 'needed' heat in my current location, and I could just put my cast iron skillet on my single burner stove for the times I might move that need/want line a little further to the left. It would certainly be easier to get out of bed in the morning if I knew I could fire this thing up and have some "sunlight" shining on me from above, and if I were to fall asleep with it on, the vent directly above it would make CO poisoning a non factor. So what say you all?

VanLifeCrisis · Jan 9, 2013

Only used the mr buddy, which would probably burn your roof down in this scenario.  I'm curious is the other types are any different.

wrcsixeight · Jan 9, 2013

How much heat do you feel directly above the Mr Buddy?  Like, how long do you estimate you hold your hand 6 inches directly above the unit, not directly in front of the hot plate?  Well both locations would be informative really. In the mean time I saw this  compact 200 watt electric only heater and added it to cart.  I'm in Florida now but I will be returning to my Van soon, and I see the temperatures have been dropping into the high 30's there lately and forecast to stay like that.  Obviously not for long term use and I won't be sitting around in my undies, but I was not planning on running such a thing too long anyway. http://www.amazon.com/Lasko-100-MyHeat-Personal-Ceramic/dp/B003XDTWN2

longjohn · Jan 9, 2013

You might check your nearest Walmart for the Lasko 200 watt heater. I got one there for around $14.

VanLifeCrisis · Jan 10, 2013

My sister has the buddy, so I will check next time im over there.  I usually stand in front of it and hold my hands above it to heat them up, havent tried to test my mettle against it <img src="/images/boards/smilies/biggrin.gif" border="0" align="absmiddle">

bee · Jan 10, 2013

I have a 3000btu cat heater and it stated in the instructions how much clearance it needed on each side.  It need the most clearance overhead.  The wall does get hot above it.  The walls on either side just a little warm.

peacetara · Jan 10, 2013

I think a "Portable Buddy" by Mr. Heater is the same kind of heater as you propose.  I have one, and this is my experience: 6" above it while on high heat, and I can barely hold my hand there for a second (maybe 2 if I'm crazy). 2' from the ceiling, on LOW heat, and the ceiling is most definitely warm if not hot. 6" above on low heat and it melted a bit of my fan (I normally have a fan just behind and above the heating part, seems to help distribute the warm air faster) when I accidentally had it too far forward. Assuming your proposed heater is the same kind, I would say you want it at least 2' from the roof. With Love, Tara

Les H · Jan 10, 2013

As close to the floor as you can get it is the place to mount it. Heat will always rise, and you need a fan to push it down towards the floor. Mount the heater low and the fan high. For most effective heating and distribution.

wrcsixeight · Jan 11, 2013

Thanks Tara, That was the info I was looking for.  I think I am going to forego the catalytic heater.  I don't know if I have anywhere to place it that would not be in the danger zone, or just darn inconvenient. Got down to  the mid 30's last night, nice to have that mattress heating pad. That Lasko 200 watt  Heater shipped within 3 hours of ordering it, and arrived the next day. It pulls around 18 amps through my inverter, and I have not left it on long enough to see how much of a dent it makes in the internal temperatures as that kind of battery draw over time, is just kind of painful to me.

oldsoul · Jan 11, 2013

i run my buddy on my kitchen countertop at 3 feet from the roof without any problems.

peacetara · Jan 12, 2013

Mine is not mounted anywhere, I just move it on top of a 5 gallon bucket when I want it.  I agree 18amps from the battery is painful.

wrcsixeight · Jan 12, 2013

I plugged in last night and ran the Lasko 200 watter all night. I certainly would not power this heater via inverter overnight unless I was deliberately trying to abuse my battery bank. Temps Dropped into the low 30's but the interior never dropped below 58f, and my Van is only lightly insulated.  It was nice not having to sit around in full winter clothing. My compressor fridge condenser fan exhausts air from the van.  Last night when it was kicking on, I could feel frigid air getting sucked in through imperfect door seals and the tiny conversion van window vents. I guess it is  finally time to add the option to reroute the condenser fan air to the interior to limit the air exchange, as it is to be nearly as cold overnight for the next few days.

wrcsixeight · Jan 13, 2013

Hmmm, the buddy heaters do not seem to be catalytic heaters, and the heat propagation will be different from a catalytic heater that radiates heat instead of heating the air through convection, So I guess the my question still stands as to how hot the catalytic heaters get in the immediate area.   I'm tempted to just go and get one to satisfy my curiosity, but I'd rather spend that money on Gasahol.

karl · Jan 18, 2013

I use a Coleman 5033 cat (I think it may be older than the sportcat?)-it pretty much lives on the floor, and gets faced toward where ever I am, I don't use fans with it. You do need to pay attention to flammable or heat sensitive materials, but by keeping 6-8" from my seats, curtains,totes,etc, have had no issues other than burning my bare ankle when I blundered into it<img src="/images/boards/smilies/rolleyes.gif" class="emoticon bbc_img">. The metal rim gets HOT. It does indeed radiate heat, rather than convection.

wrcsixeight · Jan 19, 2013

Thanks Karl. Do you think it would be possible to aim it downward after it starts glowing red? I actually like sleeping in 45 to 50f interior temps, but getting out of the bed in the morning tests my gumption, and I've been failing.  And sleeping too late ruins my mood and puts me in a bad cycle of reading all night. Radiated heat might attenuate my morning lethargy.

karl · Jan 19, 2013

Don't see why not- just want to keep it a foot or so from the ceiling-it does get hot above it more than the sides, you know- the old heat rises thing. maybe in that case a fan would be in order...a warm Hawaiianish breeze might do the trick