Terra Cotta/Flower Pot Candle Heater?

[TinaTomato]

I recall a few years ago there was a trending thing on the Internet about how to make a radiant heater using terra cotta pots and candles - anyone remember this?

I've been sorting out my options for easy, portable, DIY and - most importantly - CHEAP heating solutions for my little SUV, since a propane unit is currently beyond my means.

The YouTube videos I've encountered on how to build a terra cotta/flower pot candle heater are of both a dubious and promising nature, and I'd love it if any folks here have tried such a thing already, and can share first-hand experience.

Or, anyone have some words of wisdom to offer on the topic, with or without having tried this contraption?

 

[highdesertranger]

ain't goin to work. get a good sleeping bag. highdesertranger

 

[Spaceman Spiff]

A standard candle with a 3/32" wick will produce about 260 BTU per hour.  That is a little less than your body produces when you are sleeping.  To equal the output of a 5000 BTU heater you would need to burn about 20 candles at a cost of about $1.40 per hour.  As a comparison it would cost you about $0.70 for propane to generate 5000 BTU per hour.  So it is not cheap heat.  Plus you would have 20 fires going in your rig.  And it would take up a lot of counter/floor space.  And you would have to watch/tend 20 candles.

Burning wax candles is not healthy: [font=Verdana, Arial, sans-serif]Depending on how pure it is, parafin wax will emit H2O, CO2, Formaldehyde, Acetaldehyde, Acrolein and soot.  Imported[/font][font=Verdana, Arial, sans-serif] [/font][font=Verdana, Arial, sans-serif]candle[/font][font=Verdana, Arial, sans-serif]s can also have lead in the wick.[/font]

 

[John61CT]

Few vans are tightly insulated enough for one to make any difference.

If yours is, your body heat alone may be enough, assuming you bundle up well.

The practical version of this is a little backpackers camp stove, with an empty cast iron pan, or a full any-pot of water.

Or a Buddy heater just running the pilot light.

Any flame in your space is dangerous.

Never while asleep, always window cracked.

 

[lenny flank]

It's crap. A candle puts out about 250 BTUs per hour. Not enough to give any significant warming in a volume the size of a vehicle interior.

A good mummy sleeping bag works far far better.

 

[Stanvan]

Yes, a candle only puts out so much heat, but the terracotta stores it. And yes, some candles can put out undesirable fumes, but way less than propane. But the big yes is that they do work. I've built one, and while I haven't used it in the wild, it has been tested in a cool room. I will be using it on a trip at the end of January. I will be using votive candles to try and get a longer burn time.

 

[John61CT]

Would be barely perceptible even in a super tight insulated space.

Mostly psychological, rubbing hands together over a 15W lightbulb.

But that's worth something even if a thermometer doesn't register any change.

 

[MrNoodly]

...but the terracotta stores it

"Stores" it means it absorbs the heat the candle gives it and then releases a fraction of it over a longer time. So at any given moment you're getting less heat than the candle alone.

 

[Stanvan]

I misspoke. It also traps the heat. It does build up. We're talking two inverted pots with no venting. I got noticeable radiated heat from 2 small tea light candles.

 

[highdesertranger]

ok let me try to explain this. it doesn't matter how many flower pots you have or how you arrange them. you still only have the BTU out put of the candle(s) the pots will not increase this at all. the BTU's that go into the heating of the pots are not available to heat the space. they will spread the out put out over time but will not increase it. sure if you sick your finger in the flame it's hot but overall not many BTU's. highdesertranger

 

[Stanvan]

I hear what you're saying. But I've also felt the heat coming off of it in a room much larger than the size of my van. I'll be putting it to the test in West Virginia in January. I'll report back then.

 

[lenny flank]

Yes, a candle only puts out so much heat, but the terracotta stores it. 

It doesn't matter. What matters is BTUs per hour, and a candle simply doesn't produce that much BTU.

They don't work. It's like trying to heat your living room with a light bulb.

 

[lenny flank]

I hear what you're saying.  But I've also felt the heat coming off of it in a room much larger than the size of my van.  I'll be putting it to the test in West Virginia in January. I'll report back then.

You are confusing two different things. the heat you FEEL, and the heat that is PRODUCED. They are not the same.

If you sit right next to a lightbulb and put your hands two inches away from it, it FEELS nice and warm and cozy and fireplacey. But there is simply not enough heat there to warm up any reasonable volume of air. Same with a candle.

It just won't work. It will not heat that much space to any noticeable degree. It's a simple matter of physics and BTUs.

 

[John61CT]

I am not arguing for a tiny candle here, but three more general points are not getting through.

1. Many very effective heating systems use *radiant* energy to directly heat room contents - keeping humans warmer in freezing temps - without even trying to heat the air.

2. Super-insulated spaces with tightly controlled ventilation make a *huge* difference to energy required.

3. The perception of warmth is at least as important as objective measurements. We're not talking about survival from hypothermia, just feeling a bit more comfortable.

So put these factors together with a very limited supply of heat source fuel and a person very tolerant of cold temps most spoiled Americans would not tolerate, and a surprisingly tiny BTU input can help make things more comfortable.

 

[lenny flank]

^^^^^^^ So it will make you feel warmer if you don't mind being cold.

I'll simply advise anyone who thinks they can warm themselves with a candle and a flowerpot to... well... give it a try. You'll see for yourself that it just doesn't work. (shrug)

 

[Stanvan]

Well, I just did. I really didn't want to wait until I got to West Virginia at the end of January to find out. And I fully intended to be somewhat smug about the results. Until....

I set it in the van around 10:30. Here in Northern Virginia, we've just had our first snow of the season. Maybe 2 inches. Perfect test conditions. My 15 passenger van currently only has one seat in the back, in the third row position. The bed has been removed for an upgrade. I set the pots on a small table in the center of the floor, with a thermometer nearby, but not on the same table. 3 hours later, it hasn't gotten any warmer than the outside temps.

But I did have fun building it(like anything else I build). And learning isn't too bad either. I will be making sure my Cat heater is in good working order for WV.

 

[highdesertranger]

thanks for the follow up. highdesertranger

 

[Charlotte's Web]

^^^^^^^  So it will make you feel warmer if you don't mind being cold.

I'll simply advise anyone who thinks they can warm themselves with a candle and a flowerpot to... well... give it a try. You'll see for yourself that it just doesn't work.  (shrug)

Lenny, it helps if you burn the candle at both ends.  
Charlotte

 

[lenny flank]

 3 hours later, it hasn't gotten any warmer than the outside temps.

The laws of physics are, alas, relentless.

 

[tx2sturgis]

So, we have to find some OTHER way to warm up Tina.