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Small Cabin Forum / Off-Grid Living / Ventless Propane Heater Output?
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spencerin
Member
# Posted: 3 Nov 2019 18:46
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Just wondering about real world experiences -

I have a 336 sq. ft. cabin that's essentially a studio that I need to heat. The side walls are 8' high, but the ceiling peaks at 13.5' (these are nominal measurements - actual volume will be slightly smaller). It's in southern IN, and I'd like to be able to bring it up to 70-75* inside (max). Insulation and windows are fine/good enough.

I seem to be getting 10,000-13,000 btus as proper heat output/sizing. However, all 10,000 models I've looked at say they're applicable up to only 300 sq. ft., and the next size up (20,000) is definitely overkill. I know I can run a 20,000 at a lower output, but space is at a premium also.

I'm wondering if anybody has found these sizings to be fairly accurate, or if anybody has run what was supposed to be an undersized model without any performance problems, or what your experience is running these heaters under similar variables. Thanks in advance.

spencerin
Member
# Posted: 3 Nov 2019 18:48
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I forgot to mention - I do have 2 ceiling fans, so warm air can be redistributed from the ceiling to the floor.

Nate R
Member
# Posted: 3 Nov 2019 19:22
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Foundation type? Insulation on underside? What's outside temp when you need 70 inside?

Fanman
Member
# Posted: 3 Nov 2019 20:15
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How tight is your cabin? Because those ventless heaters put a lot of moisture and CO2 into the air, that's why they recommend leaving a window open when using them, and they're not recommended (or even legal in some jurisdictions) for sleeping rooms. I wouldn't put one in my cabin.

spencerin
Member
# Posted: 3 Nov 2019 20:16
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Pier. R6, more acting like an air and vapor barrier than anything else. 10-20*.

Just
Member
# Posted: 3 Nov 2019 20:51
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Last week I was moose hunting in northern Ont. Canada . A new guy was in camp , he went to bed with a ventless heater and a warning from the camp members .At 3am the camp woke up to the scream of a co detector. He did not ,we had to pound on his camper door for what seemed like for ever before he woke not feeling well .” Just “saying!!!

SCSJeff
Member
# Posted: 3 Nov 2019 20:51
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I switched from using a kerosene heater as supplement in our cabin bedroom to a Big Buddy heater. The kerosene heater smelled worse and definitely created moisture on the windows. I grew up in the 70s/80s with a kerosene heater on all the time and nobody was ever concerned about carbon monoxide poisoning. (Grant it, the homes back then weren't super tight)

I have a digital CO sensor in the bedroom and it has never gone above 0 with the Big Buddy (didn't have it when I used the kerosene heater). To confirm that the sensor was working, I took it out into our generator shed to test and within 5 minutes it was screaming with a number above 40 . I also don't see any moisture on the windows either...

All that being said, for whatever reason, I'm still worried about running the Big Buddy while I sleep... So I don't. (But, before I was aware of all these concerns, I routinely let the kerosene heater run all night while I slept... Go figure)

spencerin
Member
# Posted: 3 Nov 2019 21:01
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Fanman - moderately tight.

Just wondering about sizing based on real world experiences regarding sizing.

spencerin
Member
# Posted: 3 Nov 2019 23:48
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Just - did he use a tanktop attachment, or something that was really rated for outdoor use only?

Brettny
Member
# Posted: 4 Nov 2019 06:26
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Dont mess with ventless heaters while sleeping. You want to wake up the next day right?

They make these little diesel fuel heaters that are vented i believe ebay has them. Why not a wood stove?

jhp
Member
# Posted: 4 Nov 2019 09:53
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Quoting: spencerin
Just wondering about sizing based on real world experiences regarding sizing.


I have found online calculators to be pretty accurate regarding expected results, however I feel the best way to describe my real world experience is much like "there is no replacement for displacement" with engine sizing for power.

Buy the biggest heater you can afford/fit in that space and you won't be dissapointed. The few hundred extra dollars is well worth the investment for flexibility and power output when you need it.

I had an 18k BTU heater last year and it was fine, but the 28k BTU heater this year is much, much nicer. Heats faster and runs less often.

Ceiling fans on reverse at low speed help mix the air better and prevent striation but they don't do anything for preventing heat loss.

KinAlberta
Member
# Posted: 4 Nov 2019 11:26 - Edited by: KinAlberta
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Quoting: Just
Last week I was moose hunting in northern Ont. Canada . A new guy was in camp , he went to bed with a ventless heater and a warning from the camp members .At 3am the camp woke up to the scream of a co detector. He did not ,we had to pound on his camper door for what seemed like for ever before he woke not feeling well .” Just “saying!!!

Then you have to wonder about permanent brain damage or some delayed effect down the road like strokes or dementia.

People flip out over things like asbestos which is normally fine until disturbed but then willingly walk into situations where they breath in all kinds of other crap.

I grew up with coal and wood smoke from from our cabin’s old leaky stoves (plus No Pest Strips*) and still wonder if that won’t someday come back to haunt me.



* hey, lets all hang an insecticide strip in the rooms we inhabit so we too can breath in the same bug killing gases. What could go wrong?

ICC
Member
# Posted: 4 Nov 2019 12:09
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Quoting: KinAlberta
* hey, lets all hang an insecticide strip in the rooms we inhabit so we too can breath in the same bug killing gases. What could go wrong?


Lots of stuff takes a long time before damage is apparent.

Wilbour
Member
# Posted: 4 Nov 2019 13:25
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spencerin
What's keeping you from a wall hanging vented heater?

ICC
Member
# Posted: 4 Nov 2019 14:09
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I can keep a 450 sq ft cabin at 70 F when it is in the 20's outside with a direct vent wall heater that produces about 14K BTU, corrected for altitude. DV usually cost more than non-vented but have safety and health benefits. My results may not be typical. My walls are R21, floor R25, ceiling R55, widows triple pane, insulated no window door with a storm door.

cspot
Member
# Posted: 4 Nov 2019 18:44
Reply 


I used a big buddy ventless when we first got our camp in the camper. Left windows open as per the instructions. That produced a lot of moisture and with the recommended ventilation it isn't the most efficient. Also it bothered me using a ventless in a small area. When we built our cabin, I put in a wood stove and also a direct vent. Sleep much better at night knowing that it is safer.

As a sidenote I don't have electric to run the blower on my direct vent. Therefore I think it doesn't quite heat what it is supposed to for it's BTU rating. Still works great for us though. Usually since it is a recreational cabin when it is really cold the wood stove is going as well.

ICC
Member
# Posted: 4 Nov 2019 18:50
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I like being able to run both the wood stove and propane DV heater when arriving at a cold cabin. Then being able to choose one or the other. At night I let the wood burn down and the propane can kick in if it gets too cold. No having to get up in the night to reload wood. My wall heater has a fan too, but was designed to operate w/o the fan. I often turn off the inverter overnight so the propane unit heats a little slower, at some reduced rating I guess. But fine for the purpose.

cspot
Member
# Posted: 4 Nov 2019 18:56
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Quoting: ICC
I like being able to run both the wood stove and propane DV heater when arriving at a cold cabin. Then being able to choose one or the other. At night I let the wood burn down and the propane can kick in if it gets too cold. No having to get up in the night to reload wood. My wall heater has a fan too, but was designed to operate w/o the fan. I often turn off the inverter overnight so the propane unit heats a little slower, at some reduced rating I guess. But fine for the purpose.


Yes I do the same. I actually have a buddy heater in my bathroom that I will turn on when I get to the cabin to help with heating it up quicker. I also use it to preheat the bathroom before showers as our bathroom is a little distance from either heat source. It works well for that and no worries about it since it is never used when sleeping.

ICC
Member
# Posted: 4 Nov 2019 19:04
Reply 


I also use an electric blanket (gasp!!) to warm the bed mattress. The batteries are always up to 100% when I arrive so an hour or two does not really matter much. I have a three-level (something like 700, 1100 1500 watts?) 120 VAC heater in the bathroom in case I want to hasten to warm it up. It only has to run a short time so again, no big drawdown on the batteries. The bathroom/shower is the only separate space, the balance of the cabin is open with a few chests of drawers acting as dividers.

ConnyW
Member
# Posted: 11 Nov 2019 05:52
Reply 


Quoting: spencerin
Just wondering about real world experiences -

I have a 336 sq. ft. cabin that's essentially a studio that I need to heat. The side walls are 8' high, but the ceiling peaks at 13.5' (these are nominal measurements - actual volume will be slightly smaller). It's in southern IN, and I'd like to be able to bring it up to 70-75* inside (max). Insulation and windows are fine/good enough.

I seem to be getting 10,000-13,000 btus as proper heat output/sizing. However, all 10,000 models I've looked at say they're applicable up to only 300 sq. ft., and the next size up (20,000) is definitely overkill. I know I can run a 20,000 at a lower output, but space is at a premium also.

I'm wondering if anybody has found these sizings to be fairly accurate, or if anybody has run what was supposed to be an undersized model without any performance problems, or what your experience is running these heaters under similar variables. Thanks in advance.

I don't know if it's suitable for you, but I've recently purchased 2 biggest Marley baseboard heaters (if you need smaller maybe you can find them here where I read about these heaters
My cabin is of almost the same size (a little bit bigger) and this two heaters do the job, but It was too cold yet and I'm actually using just one now, but I think it'll be warn enough when it's freezing as well

Rickkrus
Member
# Posted: 11 Nov 2019 12:56
Reply 


Don't believe all this crap about these heaters not being safe. They couldn't/wouldn't say safe for indoor use if they weren't.
I have been using a Big Buddy heater as my only heat source for three years now. I live in a 19 foot travel trailer. I crack open a window just like the instructions say. The heater runs all night and day in the winter in Colorado where it has gotten down to 25 below zero. I'm still kicking.

Fanman
Member
# Posted: 11 Nov 2019 19:22
Reply 


Quoting: Rickkrus
Don't believe all this crap about these heaters not being safe. They couldn't/wouldn't say safe for indoor use if they weren't.
I have been using a Big Buddy heater as my only heat source for three years now. I live in a 19 foot travel trailer. I crack open a window just like the instructions say...


The instructions also say don't use in sleeping rooms. "Keep a window open for ventilation, and don't go to sleep" doesn't sound particularly safe to me.

For a garage or workshop, that's different.

Brettny
Member
# Posted: 12 Nov 2019 07:28 - Edited by: Brettny
Reply 


Quoting: Rickkrus
Don't believe all this crap about these heaters not being safe. They couldn't/wouldn't say safe for indoor use if they weren't.
I have been using a Big Buddy heater as my only heat source for three years now. I live in a 19 foot travel trailer. I crack open a window just like the instructions say. The heater runs all night and day in the winter in Colorado where it has gotten down to 25 below zero. I'm still kicking

I dont think an "i didnt die yet" qualifies as safe.

I have used mine on low with a window open in an unsealed shed with gabel vents and lots of cracks. I also put the wood stove in the next day.

spencerin
Member
# Posted: 14 Nov 2019 00:19
Reply 


I think y'all have convinced me, one way or another, to go vented. I also thought about electric, but after weighing all the factors of it, I'm putting it in 2nd place for now.

That said, I found some government reports about CO deaths resulting from the use of propane heaters. The # is surprisingly low - approximately 2 dozen a year. And, the report didn't mention the root causes of the CO production - improper application, faulty burner, etc. It seems to me that, when properly applied and operating as designed - they're very safe.

So, why am I going vented anyway? I'm still breathing the "exhaust", and I didn't want to risk excess moisture inside, either. And I drink a lot of vodka when I'm there , and that would play a factor in whether or not I could survive a CO event, in the very unlikely event it would happen.

SCSJeff
Member
# Posted: 14 Nov 2019 07:48
Reply 


spencerin,

I'm with you

Used and installed properly, I think they're safe (at least in regards to CO poisoning) and are really in the same category as a kerosene heater (which more people have died from spilling and burning their house down than CO poisoning). BUT... I still won't go to sleep with my big buddy running even with a cracked window and a very loud CO alarm

offgrididaho
Member
# Posted: 14 Nov 2019 10:37
Reply 


Not that the safety / CO aspect isn't important, but don't disregard the fact that non vented propane puts a lot of moisture in the air, it's a big problem on boats for sure, guess it depends on how much of a moisture problem you already have where you are.

lindenknight
Member
# Posted: 21 Nov 2019 07:51
Reply 


We have almost the same square feet as you. Started out with 200 sf cabin heated with 10,000 btu ventless heater and it did fairly well down to about 10 degrees. However, it took a long time to warm up when we first got there. When we added a 100sf bedroom it just didn’t do the job. Bought an old Thermolaire console direct vent stove on Craigslist (35,000 btu) and it heats it up quite well in about an hour. Then we turn it down low. Toasty. And I don’t worry about waking up dead. And the windows don’t get filmy like they did with the ventless heater. Always wondered if my lungs were getting filmy as well.

mj1angier
Member
# Posted: 22 Nov 2019 18:38 - Edited by: mj1angier
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Installed our ventless heater this past weekend in our 300 sq ft cabin. Gets it nice and toasty. But if it gets down to 25 3-5 times a year so, lol
We do have CO2 alarm and venting.
heater.jpg
heater.jpg


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