Candles in an igloo?

8:19 a.m. on February 4, 2019 (EST)
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I'm just finishing up a multiday process of building a 9 foot diameter igloo (using an Icebox), and my wife and I will probably sleep in it this weekend. I was thinking we might light up a dozen or so candles to generate a little warmth and maybe enough light to take some cool pictures from outside the igloo. But then I wonder if the candles might make too much CO2. We will have a vent hole in the roof and will extinguish the candles before going to sleep, so I guess we'll be OK, but I'm wondering if y'all have any wisdom on this. I know it's pretty common to operate stoves inside snow shelters, but then there are also stories about asphyxiation.

8:50 a.m. on February 4, 2019 (EST)
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My only experience is with snow shelters dug into snow/ice/whatever, but in them the temperature generally stabilizes around 32F, especially if you have a downhill entrance.  When the outside temp is zero or below, 32F is warm and toasty.

I'll bet you won't die, but CO doesn't do your abilities, either intellectual or physical, any good...

11:31 a.m. on February 4, 2019 (EST)
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I used igloo's in Yosemite when I spent the months of Jan-May there in 1980. I made many vent holes with my cross country ski poles and never had any problems with CO2 build up. And its surprising how much warmth candles make inside a snow shelter. I also used my SVEA 123 stove inside to cook on.

I notice inthe videos what show Inuit hunters and families  still using igloos and seal oil lamps that there is lil mention of air quality inside.

12:22 p.m. on February 4, 2019 (EST)
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The Native solution for light and heat is an oolik, which is a seal oil lamp with a wick.  A vent is typical in native snow shelters. 

11:53 p.m. on February 4, 2019 (EST)
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I’ve made the same igloo that I use for snowshoe outings. Thought I have only had clients in it for no more than an hour . I have used a couple of candles on some of my night time excursions. Up to 10 people and with no ill affects. Thinking that I would be more worred about the human CO2 than the candles. 

4:16 a.m. on February 5, 2019 (EST)
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Candles generate approximately 80 watts of heat, while humans generate close to 100 watts of heat at rest.  Therefore I would assume they both consume oxygen and generate carbon dioxide at about the same relative rates.  But I was an art major, not biophysicist...


6:56 a.m. on February 5, 2019 (EST)
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So I looked into it a bit more, found this tragic story involving (probably) door and vents blocked by drifting snow.

A user on this discussion thread asserts that you would wake up in a gasping panic if CO2 levels rose to toxic levels, but that would seem to incompatible with the asphyxiating quietly in sleep scenario that would apply to the first story and maybe many other accounts of small-space suffocation.

Other horror stories involve collapse of the snow structure leading to asphyxiation. In my experience so far, Icebox igloos are pretty bomber once they're finished. I usually climb up and sit on top of them. The one I'm doing now is a tough build because the snow is sugary, but once the blocks set up they are very firm. Now that I'm near the top where the blocks hang over the interior, I have to give them a few hours to set up before I can move on to the next one, so I'm basically doing one a day. The site is up in the forest about 3.5 km from my house so I just ski up there in the afternoon or evening, pack a block, then ski the long way home, come back the next day. Only 2-3 blocks left, depending on how it goes. I'll post a little report and some photos when I get the chance.

8:52 a.m. on February 5, 2019 (EST)
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Love these heated discussions......

1:08 a.m. on February 8, 2019 (EST)
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whomeworry, "Candles generate approximately 80 watts of heat"
Are you talking about 80 watts of power, continuously per hour or some other time span?

"while humans generate close to 100 watts of heat at rest."
That is inside their sleeping bag, correct over what span of time? So that is inside a sleeping bag and doesn't affect the surrounding areas?

7:51 a.m. on February 8, 2019 (EST)
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I'll step in for whome on this, at least on one issue.

Watts are a measure of energy (in this case heat)  per time, so time is already built in and "watts per hour" doesn't make any sense. 

I liked this entry I found in a discussion thread about burning 100 candles in a small room:

"According to Wikipedia "Based on measurements of a taper-type, paraffin wax candle, a modern candle typically burns at a steady rate of about 0.1 g/min, releasing heat at roughly 80 W."
So 100 candles burning, would release 80W * 100 = 8000 W

8000 W of pure heating power.

This should be enough turn your living room into a sauna...

For security, if you try this at home, leave the windows slightly open to let fresh air in, as there is a risk of death / serious health threat by carbon monoxide intoxication (when the oxygen of the room gets low)."

Except the last paragraph is misleading -- the problem with CO is not low oxygen levels but that your blood hemoglobin binds CO so tightly that, unlike CO2, it won't exchange it for O2 for delivery to the brain etc. Not good.

The eegloo she is finish. Vee sleeps in her on the morning night.

5:40 p.m. on February 8, 2019 (EST)
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BigRed said:

Watts are a measure of energy (in this case heat)  per time, so time is already built in and "watts per hour" doesn't make any sense. 


"Watts" are a measure of the amount of energy consumed per hour. So, "watts per hour" would be like saying "energy consumed per hour per hour."

"Watt-hours" describes the total amount of energy consumed over a certain period of measurement -- for example, a heat source of 100 watts that runs for half an hour would consume 50 watt-hours.

1:56 a.m. on February 9, 2019 (EST)
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The human watt rating at rest assumes no shivering, probably assumes no profuse sweating, or other activities that require burning energy to carry out.  What the person is wearing or covered with is not relevant.


10:06 a.m. on February 12, 2019 (EST)
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I'm very curious for an update, BigRed!

5:04 a.m. on February 13, 2019 (EST)
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Just did a little trip report last night. Only ended up using four or five candles, and Nancy poked holes all over the place to ventilate, but it was still relatively warm inside.

1:31 p.m. on February 14, 2019 (EST)
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i was going to suggest less candles and more openings.  the few times i have done snow caves, enough cold air was circulating that i wouldn't have been concerned about CO2.  

9:42 a.m. on February 21, 2019 (EST)
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I slept two nights in the igloo we made this last week. I kept a candle burning each night and I like the extra heat and light.  I never worry about the CO2 because my door is a tarp and breathes pretty well. 

I 100% of the time burn a candle all night as I sleep.  If I made an airtight igloo I guess I'd worry but I don't think that would be a good idea for many reasons. 

For perspective I used to sleep in my Excursion SUV with a propane buddy-heater inside all night with my dog at ski areas.  I kept one window cracked two inches.  The manufacturer of the heater recommends a nine square inch vent in the room you are heating and this burner is WAY hotter than a candle.  This heater has a low oxygen sensor/shutoff too and it never tripped. 

5:18 a.m. on February 22, 2019 (EST)
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As it turns out my wife got paranoid and poked the igloo full of holes. I filled them in later but I think they opened up again when the warm weather rolled in again over a week ago. The igloo kind of dented in on one side and lots of holes opened up, was still standing with a big hole in the roof yesterday but will probably collapse in another bout of warm weather tomorrow. All that work!

9:25 p.m. on February 24, 2019 (EST)
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In the 50+years I have been spending in the mountains and teaching winter mountaineering, none of the students had any problems in their igloos --- except for a few who were claustrophobic. The students were both adults and Scouts. We have everyone start with a tent so they would have a fall-back if they became claustrophobic (and these were often scared of tents being "strangling" as well.)

We use igloos and snow-caves, plus carving building-blocks. The problems that arise are ones where people went out in warm weather.

I have seen situations where adult Scout leaders chose a location for snow-caves on a slope that was just eager for releasing an avalanche.  There are a number of good snow-camping books that, if you read thoroughly and follow the descriptions carefully, you will have no problems (a couple of New England Universities have good books and are well-known for teaching snow skills).

OTOH, I have seen people who spent a lot of their effort creating a tightly sealed igloo or snow cave, putting a lot of effort into smoothing  the entire surface of their shelter with no holes or vents, but crowding way too many occupants in.

9:30 p.m. on March 6, 2019 (EST)
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We tried using candles a bit in the igloo and had no problems with CO but we stopped using them because they were always a mess.

We did get a CO meter after a couple years of iglooing to see just what was happening with our stove and lantern.

When we had the canister Primus stove and lantern both burning, the highest we saw was 15ppm. When we used a white gas stove, I believe it was a Whisper Light, the meter usually read around 23-25ppm.

We had a Kestrel weather meter and measured the speed of the air going out the top vent. The vent was the same size as the fan opening and we had an air speed of 5 to 7 mph depending on the wind outside.

Those boys in Kosciuszko National Park got buried by heavy falling/drifting snow. I've found that snow falling on the igloo leaves a vent up through the falling snow with the wind speed and warmth that melts it. If it is windy, the vent goes sideways as the snow accumulates but it has always stayed open for me. In the snowcave those boys had, they had ground drifting going over their vent hole.

Our lantern will maintain 48f. at the ceiling, 42f. at chest level and 38f. at the floor. That is when the outside temp is not below zero f.  A couple candles will do the same.

We did an experiment once, had a dual burner Coleman white gas stove full blast on both burner, a dual mantel Coleman lantern and my Primus canister stove and lantern all burning full blast. The igloo went from 48f. to 52f. at the ceiling. Holes immediately strated melting through the ceiling. I'd say any more than four candles would be a waste of heat and two should be plenty.

We once built a snowcave near a summit and had our door and vent drift shut. I kept waking up in the night and then one time I noticed my Bic lighter was burning strange. The flame was a couple inches above the lighter and I pulled back the tarp to check the door. It was drifted in plump full. The vent hole was also closed. We took a ski pole and poked a hole up through the roof. An inch and half hole had my lighter burning normally after 15 minutes.


9:17 a.m. on March 7, 2019 (EST)
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Thanks for sharing all of that helpful info, Ed!

11:31 a.m. on March 9, 2019 (EST)
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The title of this thread causes Elton John to get stuck in my head. Yes, I realize it's a stretch, but I'm a helpless pawn before the ramblings of my mind.

11:59 a.m. on March 11, 2019 (EDT)
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Zalman said:

The title of this thread causes Elton John to get stuck in my head. Yes, I realize it's a stretch, but I'm a helpless pawn before the ramblings of my mind.


April 7, 2020
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