2 comments on have the right to a flower pot and tealight candle develop enough warmth to conserve you in a cold emergency?

We’ve been trial and error various prepping memes, like turning oranges right into candles and also using Doritos to start fires. Approximately this time the year we often see world share memes about using tealight candles and also a terracotta pot to craft a DIY heater.

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So we built a couple of various versions ourselves and also measured the results.

Yes, friend can gain a how amazing amount of warmth from this setup. However it doesn’t job-related the means some think the does. The same amount of warm is coming the end of the candles whether there’s a pot above them or not, for this reason it’s not that you ‘making the candle hotter.’

Instead, through concentrating the warm into a small area making use of a material like terracotta that have the right to hold and radiate heat, you can get enough warmth in a tiny area (very small) to keep yourself alive — yet you won’t be heater up a normal room in her house.

This deserve to work once you want to heat a “personal” quantity of space, such as a tent, under a tarp shelter, in a closet or tiny bathroom, or in a vehicle that’s grounding overnight in winter.

But that tiny amount of heat comes with large risks. Open-flame candles are currently one the the leading causes of residence fires. And also now you’re developing a potential rough setup by stacking things on height of every other, etc etc. The wax chin can even reach that is flash allude — see below for videos of someone burning under their watercraft this way.

So this is a neat hack to recognize about, yet not something you should pick to count on. For preparing ahead of time, gain a appropriate portable room heater or candle lantern instead.


Four tealight candles acquired the exterior that a terracotta pot up to 270°F (132°C), if a single candle got it approximately 127°F (53°C).It would certainly take practically 60 candle to effectively heat a 100-square-foot room.You could boil water or even cook directly on the terracotta this way.Heat is no “amplified” with these devices, just concentrated.But that focused heat additionally comes with meaningful dangers.That focused heat can be sufficient to warm tiny spaces.So shrink her shelter space instead of expanding your candles.

More: Best emergency candles

The theory

There are several methods to do a terracotta heater. The basic an approach is to usage a pair of bricks come elevate a terracotta pot, location a few tealight candles under the pot, and also light the candles.

There are a pair of said theories because that why this must work. One is that the terracotta pot(s) and the optional bolt in which method amplify the heat from the tealight candles. This is literally impossible, as it violates the an initial two rule of thermodynamics. Things don’t simply magically obtain hotter without including extra inputs.

A much more realistic concept of the terracotta heater’s procedure is the it concentrates the warm from the candles into a smaller room instead of simply spreading the energy approximately the room.

Example indigenous the video below whereby the flower pot basic holds the candles, v a steel rod holding the totality system together (running vertically v the center)

You might see various other variations of structure these heaters, such as sticking a smaller sized pot in the large pot and adding a metal bolt in the center — however you shouldn’t perform that, since those kinds of bolts are often galvanized, and galvanized metal provides off toxicity zinc fumes when heated.

The math behind candle heat

Can a candle heat an entire room? If not, how many candles would certainly it take? Thankfully, we can do part math to find out. Warm is measure in brother Thermal units (BTU). A single candle produces all over from 75 come 85 BTU, i m sorry we’ll median to 80 for our calculations.

Next, recognize the square clip of the room you want to heat. Let’s assume a 10-by-10 square room, for this reason 100 square feet.

Calculating how plenty of BTUs you need per square foot is tricky, because it’s dependent on location. The United says is break-up into eight climate zones. Ar 1, the warmest, consist of the pointer of Florida, when Zone 8 covers the coldest components of Alaska.

Let’s assume her 100-square-foot room is in zone 4, putting it in the middle of the country. Ar 4 requirements 45 BTUs every square foot, therefore a solitary candle could effectively heat a room the one foot, ripe inches—not even two square feet.


Your 100-square-foot room would require 4,500 BTUs to be heated effectively, which would certainly take over 56 candles. Through comparison, a Mr. Heater large Buddy Portable Heater can put the end 18,000 BTUs.

See our guide to the best room heaters for more on identify how numerous BTUs you require in a heater.

The very first test

The initial goal to be to build and also test such a heater come see exactly how well it might actually heat. We began with a small four-inch pot and also placed 4 tealight candles underneath, every on top of a sheet of aluminum foil to safeguard the countertop. We necessary something come prop up the pot, yet didn’t have bricks laying around. For this reason we made decision to simply use a few extra tealight candles together a base. This turned the end to it is in foolish, yet instructive.


We lit the candles, collection the pot ~ above top, and set a timer for ten minutes. We used an infrared thermometer to monitor the temperature the the pot. One snag in the test: after about four minutes, us noticed that among the candles had gone out. We relocated the pot (then so warm that stove mitts were required), relit the candle, and also put the pot back.

Despite that snafu, the pot gained impressively hot. After 10 minutes, us measured the pot at simply under 270°F (132°C), which was method more warm than we had assumed 4 tealight candles can produce.


We chalked it up together a success, but also a source of concern. Just just how hot can one of this pots get? What if someone touched it? would certainly the warm melt Formica countertops?

The dumb idea to stack extra candle to support the terracotta pot actually gave us a data allude to think about. The wax in the unlit candles had actually melted wherein it had actually been inside/under the heated pot. The made us begin thinking that possibly this homemade tool was getting too hot. We determined to do much more research prior to further experimentation.

Notice the summary in the unlit candles, whereby the wax began melting indigenous the contained heat.

Candle wax can get too hot

A potential problem is creating so much concentrated heat underneath the pot the the candle wax chin ignites.

Most candles room made that a substance dubbed paraffin, i m sorry is a byproduct that petroleum distillation. If there room some wellness concerns about soot created by paraffin candles, that a mostly safe substance, used not just in candles, yet for keeping food, lubricating machines and bullets, wax surfboards, make crayons, and also it’s also an ingredient in some chewing gums.

Paraffin is greatly safe, assuming the doesn’t obtain too hot and also reach that is flash allude — the temperature at which that is vapors deserve to ignite.

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The flash point of paraffin is about 400°F (204°C). You’ll never get close to that temperature native a solitary candle. But if you put several candle together and cover them v an insulator favor a teapot, they can easily get that hot.

This isn’t just theoretical. Miles Weston set his boat on fire after ~ the paraffin in his terracotta heater ignited: