Keeping warm in sub-freezing weather, using only a tiny amount of fuel for heat.

[rruff]

Can’t you have the intake pull warm air from the inside like a house heater does?

No, you need fresh air... else you'll die. House heaters are furnaces with heat exchangers; the combustion is vented to the outdoors... it doesn't use your interior air.

You don't need a lot of air if it's a small flame though. I'd guess most setups already leak enough... but crack a window a 1/4 inch to be safe.

 

[danoinvt]

Don't overlook old school solutions. I am talking about the old fashioned soapstone foot warmers. Basically a slab of rock cut flat on both sides, then heated over campfire, propane, car engine, etc. Then place at the foot of the bed wrapped in a towel to keep you warm all night. Depending on how hot you get it, they can even be used to help keep a meal or cup of coffee warm. You can often pick them up from ebay or etsy for around $50, plus shipping. Also they can be bought new from the link that follows, and no, I don't work for them. Just a fan of soapstone, and heat retention is one of it's better known properties. https://vermontsoapstone.com/products/handmade-soapstone-bed-warmers/

I totally agree with CosmickGold. As one who grew up in Vermont (in an unheated upstairs bedroom in a pretty-much uninsulated house), warm feet in bed make a huge difference. Sometimes a winter cap helps, too.

Said house wasn't far from Vermont Soapstone Company (stop by their place if you're in the area, nice people carrying on a traditional craft). Their products are quality. Great price--with shipping, no less.

 

[danoinvt]

I use an 'old skool' externally vented convective propane furnace in my current rig, which is an '85 Winnebago Chieftain. It's not nearly as well insulated as my previous steppy & struggles to heat the rear bedroom section at -25C, whereas it easily heated the whole steppy, minus the driving area (which was partitioned off). I just picked up a Pomoly Dweller wood stove which I plan to use next winter, alongside of the propane furnace in my next rig.
When it comes to keeping warm/cool I find that as much insulation as practical is key & can greatly reduce the amount of energy needed for heating/cooling. It's also better to adhere to the KISS principle which, in my case, means little or no electronic regulation of my heating/cooling sources. I don't stay in town & boondocking for extended periods means I put a premium on reliability & the ability to (cheaply) repair what I have. Also, up here in Canada, means much less solar in the winter so any heater that draws current in order to operate is a non-starter for me. I DO have a small Honda EX650 generator, if needed, to run my tablet/phone/lights/compressor coolers, but that's (barely) taken care of by my solar setup. ..Willy.

Just curious on what size rig you plan to heat with the Pomoly Dweller? Planning a renovation. Thanks!

 

[Willy]

I'm leaning towards an F250/350 with an older larger camper on it, but a lot depends on what I see for sale. Hell, I might even go for another steppie or mini school bus. ..Willy.

 

[Spaceman Spiff]

Don't overlook old school solutions. I am talking about the old fashioned soapstone foot warmers.

Any thermal mass will do; don't have to be expensive. My grandma would heat her iron on the wood burning kitchen stove for us kids at night, wrapped in a couple of towels. I have known guys that use plain, old rocks.
I use a modern version of an old fashioned hot water bottle. Water is easily heated on a camp stove.

 

[bagabum]

If you want to us e regular candles, I think these are a great deal. Not sure how much energy burning paraffin puts out relative to other fuels, or the fumes/soot... but they are only $1.25 each at dollartree. I have used candles like this a lot and had no ill effects. I think they last over 10 hours and definitely warm a well insulated rig.

""Not sure how much energy burning paraffin puts out"" A typical candle flame puts out about 80 Btu, an average person generates about 320 Btu (250 sleeping), so having 4 candles burning would be the equivalent of an extra person sitting with you.

Maybe a better option would be propane provided that you use bulk containers. Probably much cleaner, and pretty cheap. Buddy heaters are just too much IMO. This would be a good option: https://www.amazon.com/Coleman-Prop...ds=mini+propane+lantern&qid=1674668196&sr=8-6

 

[dreamrunnerjt]

Last winter I was so used to wearing face mask that occasionally in bed the air seemed too cold to breathe. I put a mask on but always woke up with it off.

 

[Frood]

If you want to use regular candles, I think these are a great deal. Not sure how much energy burning paraffin puts out relative to other fuels, or the fumes/soot... but they are only $1.25 each at dollartree. I have used candles like this a lot and had no ill effects. I think they last over 10 hours and definitely warm a well insulated rig.

From everything I have seen the candle solution is of very limited value. It may create a better atmosphere but the amount of actual heat is minimal, despite being able to get an overturned flowerpot to a decent temperature. The main issue here is that even if you get a flowerpot up to 120 degrees, that just means that the flowerpot is warm. What you really need to do is get the air in your vehicle warm by sucking the heat out of that flowerpot. Generally I think open flame in a vehicle is a very bad idea... You may be find 99 times, but that ONE time you accidentally knock it over and spill burning oil or wax all over the interior of your vehicle isn't worth the risk. Especially when you consider how much you would wind up spending to burn enough candles when compared to safer methods with other fuel types.

 

[Camper]

Get a real heater and be warm...

 

[user 22017]

From everything I have seen the candle solution is of very limited value. It may create a better atmosphere but the amount of actual heat is minimal, despite being able to get an overturned flowerpot to a decent temperature. The main issue here is that even if you get a flowerpot up to 120 degrees, that just means that the flowerpot is warm. What you really need to do is get the air in your vehicle warm by sucking the heat out of that flowerpot. Generally I think open flame in a vehicle is a very bad idea... You may be find 99 times, but that ONE time you accidentally knock it over and spill burning oil or wax all over the interior of your vehicle isn't worth the risk. Especially when you consider how much you would wind up spending to burn enough candles when compared to safer methods with other fuel types.

It depends. Do you just want to take the chill off or do you want it toasty? Are you trying to heat an RV, a tent or a pickup topper?

This HVAC guy says they are as efficient as a space heater:

https://hvacguides101.com/how-many-candles-to-heat-a-room/
Maybe someone can find a better source. I didn't look very hard. He says you would need 20 candles to heat a room and forget trying to heat a tent with them.

 

[Frood]

It depends. Do you just want to take the chill off or do you want it toasty? Are you trying to heat an RV, a tent or a pickup topper?

This HVAC guy says they are as efficient as a space heater:

https://hvacguides101.com/how-many-candles-to-heat-a-room/
Maybe someone can find a better source. I didn't look very hard. He says you would need 20 candles to heat a room and forget trying to heat a tent with them.

This guy actually goes into some of the math and science behind it...

https://theprepared.com/blog/can-a-...-enough-heat-to-save-you-in-a-cold-emergency/
I did some googling as well and got the following info:
1 Watt = 3.41 BTU/hour
Tea-light produces 75-85 BTU's of heat
Tea-light candle burns for about 4 hours

If you burn enough candles, of course you can heat a room with them. That doesn't make it a good idea when there are far safer and cost-effective methods out there. The HVAC guy above does his conversion from BTU -> Watts wrong though... 80 watts = 272 BTU/Hr = 3.4 candles burning at a time for one hour (since candles produce 75-85 estimated BTU)

So an 800 watt space heater (which is a smallish space heater) would be equal to burning 34 candles at a time for one hour. So you can burn the candles or run a heater for 4 hours (how long tea lights approximately burn).

So yeah, it can work but that doesn't make it safe or cost effective considering you can run a Mr. Buddy for 4 hours/day on low setting for over 20 days with a 20 lbs propane tank (which at my local convenience store can be switched out for $24). And there is a MUCH lower chance of catastrophic fire with decently maintained equipment and basic safety precautions...

Of course you don't get the same ambiance and warm gentle lighting from a space heater as you would from candles.

 

[rruff]

This HVAC guy says they are as efficient as a space heater.

He may be a tech... but he doesn't seem to understand energy, power, heat, and efficiency... so I'm doubtful.

If a candle puts out only 25W of heat, that's less than I thought. Obviously this will vary because not all candles are the same. So I looked on the internet and got reports all the way from 6W to 100W! I hoped to find an actual test of a prayer candle, but did not. I've had no more than two running at a time in my rig, and they seemed to help. I did not keep track of time unfortunately, and it was a long time ago so I don't remember how often they needed replacing... but it seemed like only a week or so, with ~5 hours per day... or 35 hrs?

A 12oz prayer candle has ~306g of wax, assuming that 12oz is a volume measurement and not weight. If it's weight it would be ~10% more. Wax releases ~42,000 J/g when burned, so the candle contains 12.85MJ of energy. Dividing by 3600 gives us 3,570 W-hr.

Power output, burn time:

25W, 143hrs
50W, 71hrs
75W, 48hrs
100W, 36hrs

However... people online say these last 80hrs to 7 days (168hrs). Easy enough to do an experiment though, by trying them out and keeping track of how long they go.

If you need 12 candles to put out 300W (enough to heat a well insulated rig 20F above ambient)... no way would I hang out in those fumes. It would look cool though! And even if only 3 is enough, they cost 2x the price of bulk propane.

 

[Night_Sailor]

I just had the good fortune of two nights of 19F cold outside as I slept in my van. I say "good fortune" because it's rare to have a winter where temps ever drop into the teens even once here in Arlington, Texas. These two nights of cold were just what I needed to test my van for winter warmth, and the test was a marvelous success, requiring only a tiny amount of heating fuel.

No one uses electric heat from house batteries to heat their entire van, as the electrical drain would be tremendous, killing the batteries. But I don't need to heat the whole van, I only need heat myself as I sleep. That's the trick, focus on heating yourself, not the whole van. It only takes a tiny fraction of the electricity to heat one person, as it would take to keep an entire van warm.

View attachment 29876
So yesterday I installed this 12-volt jack on the wall right next to my bed.

View attachment 29877
I also bought this 12V electric car blanket to plug into it while I sleep. At bedtime, I set this blanket to medium and wrapped it around my chest over my T-shirt, then put on a comfortable thin-but-insulated jacket and zipped it up over the electric blanket. Then I went to bed under two regular blankets. (It's amazing how much warmer two blankets are than one, regardless of what two blankets you use.)

I also had thick socks on my feet to ensure my toes stayed warm, and insulated gloves on my hands (required by my too-easy-to-chill fingers). Then I slept in total comfort, toasty warm all over! The cold was not uncomfortable to breathe, because my body was so warm. (I cut a small slit in two of the glove fingers so I can still use the touch screen of my cell phone even with the gloves on.)

I'd been concerned I might be wrong about the power draw, and might be about to kill my house batteries before dawn. But checking the gauge in the morning, I found the pull on my batteries had only dropped them 0.2 volts. (What a relief.) Now during the day, the solar panels can bring them right back up again.

Concerned water in the van might freeze, expand, and break containers and pipes, I keep the van about 10 degrees above freezing, ensuring all water stays in the liquid state. So I have a propane furnace with a thermostat on the wall, which I set to 41 degrees F. Set so close to the outside temperature, it requires very little propane to accomplish my goal even when temperatures are in the teens outside.

Planning well ahead for this, I have my van fully insulated on walls and ceiling with HaveLock wool. The metal van floor is covered with a layer of inch-think foam insulation, and that is covered with a layer of white linoleum. This combination makes my floor very soft on my knees. I cringe when I see videos of people putting hardwood floors in their vans, having seen pictures of the damage and callouses done to knees of van dwellers who must crawl over a hard floor every day. My floor actually feels good on my knees when I need to get down there for something.

I have lots of windows for light, but to keep the cold out, I cut a section of that inch-thick foam for each window. These covers are held in place by a bungee cord over each window running from top to bottom over the center of each. Then I place a two-inch-square block of wood under each bungee cord at the window's center to hold that foam insulation firmly against the glass. (Works like a charm.)

Having made all these insulation preparations -- and by keeping the temperature only a little above freezing -- the propane needed to heat my van is as insignificant as my mini electric blanket's drain on my batteries. Warmth in my van is almost free!
_________________________

But be sure to have backup ways of staying warm! I have two propane tanks so if one goes empty, the regulator automatically switches over to the second tank and shows me a red warning that the first tank is empty. (After I refil the first tank, the red warning will show when the second tank goes empty)

But what if batteries go dead and I can't run the furnace? As my furnace backup, I have a little cook stove burner connected to the same propane line, normally shut off both at the stove and at a valve on the wall.

But what if both tanks run out of propane? I doubt I'll ever let that happen; yet to be safe, I have plenty of blankets and warm clothing to put on (plus my little electric blanket to use if I still have electricity).

Cold winters should be fun, not brutal!

 

[DRAGNSHIP]

No mention yet of a tiny wood burner? My GF has one that she bought online, installed in her camper...it's pretty nice and she tiled the walls around it. Also, a person could build a small rocket stove if they are handy, and even add some mass to it for more/longer term broader heating ability. I live in KY and there is always some wood available for free somewhere if you have a hatchet. I understand it's not the cleanest or most convenient but it's off-grid and could be essentially a free running cost along with low initial cost.

They do need stuffed with more wood pretty often when small but there are ups and down to anything in life. My vehicle seems like a good candidate for a small wood burner since I have toolboxes built into the body and could store dry wood in one. Been wanting to cut interior access doors to a few of them anyways...12' Spartan Supreme service box van

 

[Happy Camper]

There is a thread on that here.
https://vanlivingforum.com/threads/wood-stoves.47992/

 

[quilting22]

I just had the good fortune of two nights of 19F cold outside as I slept in my van. I say "good fortune" because it's rare to have a winter where temps ever drop into the teens even once here in Arlington, Texas. These two nights of cold were just what I needed to test my van for winter warmth, and the test was a marvelous success, requiring only a tiny amount of heating fuel.

No one uses electric heat from house batteries to heat their entire van, as the electrical drain would be tremendous, killing the batteries. But I don't need to heat the whole van, I only need heat myself as I sleep. That's the trick, focus on heating yourself, not the whole van. It only takes a tiny fraction of the electricity to heat one person, as it would take to keep an entire van warm.

View attachment 29876
So yesterday I installed this 12-volt jack on the wall right next to my bed.

View attachment 29877
I also bought this 12V electric car blanket to plug into it while I sleep. At bedtime, I set this blanket to medium and wrapped it around my chest over my T-shirt, then put on a comfortable thin-but-insulated jacket and zipped it up over the electric blanket. Then I went to bed under two regular blankets. (It's amazing how much warmer two blankets are than one, regardless of what two blankets you use.)

I also had thick socks on my feet to ensure my toes stayed warm, and insulated gloves on my hands (required by my too-easy-to-chill fingers). Then I slept in total comfort, toasty warm all over! The cold was not uncomfortable to breathe, because my body was so warm. (I cut a small slit in two of the glove fingers so I can still use the touch screen of my cell phone even with the gloves on.)

I'd been concerned I might be wrong about the power draw, and might be about to kill my house batteries before dawn. But checking the gauge in the morning, I found the pull on my batteries had only dropped them 0.2 volts. (What a relief.) Now during the day, the solar panels can bring them right back up again.

Concerned water in the van might freeze, expand, and break containers and pipes, I keep the van about 10 degrees above freezing, ensuring all water stays in the liquid state. So I have a propane furnace with a thermostat on the wall, which I set to 41 degrees F. Set so close to the outside temperature, it requires very little propane to accomplish my goal even when temperatures are in the teens outside.

Planning well ahead for this, I have my van fully insulated on walls and ceiling with HaveLock wool. The metal van floor is covered with a layer of inch-think foam insulation, and that is covered with a layer of white linoleum. This combination makes my floor very soft on my knees. I cringe when I see videos of people putting hardwood floors in their vans, having seen pictures of the damage and callouses done to knees of van dwellers who must crawl over a hard floor every day. My floor actually feels good on my knees when I need to get down there for something.

I have lots of windows for light, but to keep the cold out, I cut a section of that inch-thick foam for each window. These covers are held in place by a bungee cord over each window running from top to bottom over the center of each. Then I place a two-inch-square block of wood under each bungee cord at the window's center to hold that foam insulation firmly against the glass. (Works like a charm.)

Having made all these insulation preparations -- and by keeping the temperature only a little above freezing -- the propane needed to heat my van is as insignificant as my mini electric blanket's drain on my batteries. Warmth in my van is almost free!
_________________________

But be sure to have backup ways of staying warm! I have two propane tanks so if one goes empty, the regulator automatically switches over to the second tank and shows me a red warning that the first tank is empty. (After I refil the first tank, the red warning will show when the second tank goes empty)

But what if batteries go dead and I can't run the furnace? As my furnace backup, I have a little cook stove burner connected to the same propane line, normally shut off both at the stove and at a valve on the wall.

But what if both tanks run out of propane? I doubt I'll ever let that happen; yet to be safe, I have plenty of blankets and warm clothing to put on (plus my little electric blanket to use if I still have electricity).

Cold winters should be fun, not brutal!

So glad your able to stay warm when needed. I have a small uninsulated 1500 Promaster cargo van. Keeping warm is no problem without using anything then the vehicle heater when l first get up. I put an electric blanket over my top sheet then 2 thin fleece blankets to keep the heat from escaping. I don't turn the electric blanket on until abt 2am when l notice the cold starting to get uncomfortable.Just need to turn it to 1-2 on the dial. Everything is plugged into my Vtoman power station. Didn't like my power station when l first got it, but as l expected it was due to user error...that would be me ! After small learning curve (l'd never lived in a vehicle - always had sticks.n' bricks), l'm warm and happy. Except quick potty break in the middle of the night. My electric blanket isn't expensive or fancy and doesn't use much power. Granted only have had a few nights where temp around low 30's.

 

[user 22017]

Everything is plugged into my Vtoman power station. Didn't like my power station when l first got it, but as l expected it was due to user error...that would be me !

I bought a Vtoman power station. I haven't tried mine yet. How long have you had yours? Do you have solar panels, too?

 

[RonDean]

So glad your able to stay warm when needed. I have a small uninsulated 1500 Promaster cargo van. Keeping warm is no problem without using anything then the vehicle heater when l first get up. I put an electric blanket over my top sheet then 2 thin fleece blankets to keep the heat from escaping. I don't turn the electric blanket on until abt 2am when l notice the cold starting to get uncomfortable.Just need to turn it to 1-2 on the dial. Everything is plugged into my Vtoman power station. Didn't like my power station when l first got it, but as l expected it was due to user error...that would be me ! After small learning curve (l'd never lived in a vehicle - always had sticks.n' bricks), l'm warm and happy. Except quick potty break in the middle of the night. My electric blanket isn't expensive or fancy and doesn't use much power. Granted only have had a few nights where temp around low 30's.

It's that nighttime potty break(s) that keeps me from bundling up. Them young whippersnappers wouldn't understand!

 

[islanderxx]

It's that nighttime potty break(s) that keeps me from bundling up. Them young whippersnappers wouldn't understand!

I understand.

 

[islanderxx]

This guy actually goes into some of the math and science behind it...

https://theprepared.com/blog/can-a-...-enough-heat-to-save-you-in-a-cold-emergency/
I did some googling as well and got the following info:
1 Watt = 3.41 BTU/hour
Tea-light produces 75-85 BTU's of heat
Tea-light candle burns for about 4 hours

If you burn enough candles, of course you can heat a room with them. That doesn't make it a good idea when there are far safer and cost-effective methods out there. The HVAC guy above does his conversion from BTU -> Watts wrong though... 80 watts = 272 BTU/Hr = 3.4 candles burning at a time for one hour (since candles produce 75-85 estimated BTU)

So an 800 watt space heater (which is a smallish space heater) would be equal to burning 34 candles at a time for one hour. So you can burn the candles or run a heater for 4 hours (how long tea lights approximately burn).

So yeah, it can work but that doesn't make it safe or cost effective considering you can run a Mr. Buddy for 4 hours/day on low setting for over 20 days with a 20 lbs propane tank (which at my local convenience store can be switched out for $24). And there is a MUCH lower chance of catastrophic fire with decently maintained equipment and basic safety precautions...

Of course you don't get the same ambiance and warm gentle lighting from a space heater as you would from candles.

The presentation is invalid because he did not give the specification when doing the test. They did say 100 sq/ft but did not include the height; the volume is important. The temperature in Zone 4 could vary by 50° F. He did not mention insulation or heat loss to the surface of the walls. Did he not mention any time in calculating BTU and fuel use? There are too many missing factors that would validate his theory.