2 comment on have the right to a flower pot and tealight candle develop enough heat to save you in a cold emergency?

We’ve been trial and error various prepping memes, like transforming oranges into candles and using Doritos to begin fires. Around this time that year we regularly see civilization share memes around using tealight candles and a terracotta pot to craft a DIY heater.

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So we developed a pair of different versions ourselves and also measured the results.

Yes, friend can get a how amazing amount of warm from this setup. Yet it doesn’t work the method some think the does. The same amount of warm is coming out of the candles whether there’s a pot above them or not, so it’s no that she ‘making the candle hotter.’

Instead, through concentrating the warmth into a tiny area utilizing a material like terracotta that have the right to hold and radiate heat, you deserve to get enough warmth in a little area (very small) to store yourself alive — however you i will not ~ be heating up a regular room in her house.

This can work as soon as you want to warmth a “personal” quantity of space, such together a tent, under a tarp shelter, in a closet or small bathroom, or in a automobile that’s stuck overnight in winter.

But that tiny amount of warm comes with big risks. Open-flame candle are currently one that the leading reasons of house fires. And also now you’re creating a potential stormy setup by stacking points on top of each other, etc etc. The wax itself can even reach the flash point — see listed below for videos of who burning under their boat this way.

So this is a succinct hack to understand about, but not something you should select to count on. Because that preparing front of time, gain a ideal portable room heater or candle lantern instead.


Four tealight candles gained the exterior the a terracotta pot up to 270°F (132°C), when a solitary candle acquired it approximately 127°F (53°C).It would certainly take virtually 60 candle to successfully heat a 100-square-foot room.You can boil water or even cook directly ~ above the terracotta this way.Heat is no “amplified” through these devices, only concentrated.But that concentrated heat also comes with systematic dangers.That focused heat have the right to be sufficient to warm little spaces.So shrink your shelter space instead of widening your candles.

More: Best emergency candles

The theory

There room several ways to make a terracotta heater. The basic technique is to use a pair of bricks come elevate a terracotta pot, location a couple of tealight candle under the pot, and also light the candles.

There space a pair of argued theories because that why this must work. One is that the terracotta pot(s) and the optional bolt in which method amplify the warmth from the tealight candles. This is accurate impossible, together it violates the very first two rules of thermodynamics. Things don’t just magically get hotter without adding extra inputs.

A more realistic theory of the terracotta heater’s procedure is the it concentrates the warmth from the candles into a smaller room instead of just spreading that energy approximately the room.

Example indigenous the video clip below wherein the flower pot basic holds the candles, with a steel rod hold the totality system together (running vertically v the center)

You could see other variations of building these heaters, such together sticking a smaller sized pot in the big pot and adding a metal bolt in the facility — but you shouldn’t execute that, due to the fact that those type of bolts are regularly galvanized, and also galvanized metal offers off toxicity zinc fumes when heated.

The mathematics behind candle heat

Can a candle heat whole room? If not, how numerous candles would it take? Thankfully, we can do some math to find out. Warm is measure up in british Thermal devices (BTU). A solitary candle produces almost everywhere from 75 to 85 BTU, i beg your pardon we’ll median to 80 for our calculations.

Next, recognize the square footage of the room you want to heat. Stop assume a 10-by-10 square room, so 100 square feet.

Calculating how plenty of BTUs you require per square foot is tricky, due to the fact that it’s dependence on location. The United says is separation into eight climate zones. Ar 1, the warmest, consist of the reminder of Florida, when Zone 8 consists the coldest components of Alaska.

Let’s assume her 100-square-foot room is in region 4, putting it in the middle of the country. Region 4 needs 45 BTUs per square foot, for this reason a single candle could effectively heat a room of one foot, ripe inches—not even two square feet.


Your 100-square-foot room would need 4,500 BTUs to it is in heated effectively, which would take over 56 candles. By comparison, a Mr. Heater huge Buddy Portable Heater can put out 18,000 BTUs.

See our overview to the best an are heaters for an ext on determining how numerous BTUs you need in a heater.

The very first test

The original goal to be to build and test such a heater come see exactly how well it could actually heat. We began with a tiny four-inch pot and also placed 4 tealight candle underneath, all on peak of a paper of aluminum silver paper to safeguard the countertop. We required something to prop up the pot, but didn’t have bricks laying around. For this reason we chose to just use a few extra tealight candles as a base. This turned the end to it is in foolish, yet instructive.


We lit the candles, set the pot on top, and set a timer for ten minutes. We used an infrared thermometer to screen the temperature of the pot. One snag in the test: after around four minutes, us noticed that among the candles had actually gone out. We relocated the pot (then so warm that range mitts were required), relit the candle, and put the pot back.

Despite the snafu, the pot acquired impressively hot. ~ 10 minutes, us measured the pot at simply under 270°F (132°C), i m sorry was way more warmth than we had actually assumed four tealight candles might produce.


We chalked that up together a success, but also a source of concern. Just how hot might one of these pots get? What if who touched it? would certainly the heat melt Formica countertops?

The dumb idea to stack extra candles to support the terracotta pot actually offered us a data point to think about. The wax in the unlit candles had melted whereby it had actually been inside/under the boil pot. That made us start thinking that perhaps this homemade device was acquiring too hot. We made decision to do an ext research prior to further experimentation.

Notice the rundown in the unlit candles, wherein the wax began melting native the included heat.

Candle wax can obtain too hot

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

Most candles space made that a substance referred to as paraffin, i m sorry is a byproduct the petroleum distillation. While there are some wellness concerns about soot created by paraffin candles, the a largely safe substance, used not simply in candles, yet for preserving food, lubricating machines and also bullets, wax surfboards, making crayons, and it’s also an ingredient in part chewing gums.

Paraffin is mostly safe, assuming the doesn’t gain too hot and also reach that is flash point — the temperature at which that is vapors can ignite.

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The flash allude of paraffin is roughly 400°F (204°C). You’ll never acquire close to that temperature from a solitary candle. Yet if you placed several candles together and cover them v an insulator prefer a teapot, they can easily obtain that hot.

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