What is a clay pot candle heater, and is it worth building? (With steps)

A big part of survival is making sure you’re sufficiently warm. Normally, you rely on various machines and contraptions to provide heat to the household, but what if those options become unavailable to you?

In a prolonged grid outage, electricity may be out of the equation, especially if you don’t have a generator on your property. You might not have a fireplace/woodstove, rendering you unable to make use of firewood indoors. And if you own a catalytic gas heater, your last tank of propane might be on its way out.

So what then? Sounds like a pretty terrible spot to be in in the dead of winter, doesn’t it? That being said, we ARE envisaging an abnormally desperate situation here.

So here’s where the clay pot candle heater comes in. If all other means of getting heat into the home are exhausted, this nifty little device can be built with items commonly found around households.

It’s a very simple contraption. At its simplest level, it is comprised of only two types of items- terracotta pots and tea light candles (using paraffin for the wax).

If you so wish to construct something more complex (there are some benefits to this), you’ll only need a few more bits and bobs. But more on the specifics later, because there are some things worth mentioning first before you continue reading.

The clay pot candle heater is not a one-size-fits-all kind of solution. There are some situations it’ll work in, and others it won’t.

It is best used in a specific manner, and if you make your own clay pot heater with a completely different set of expectations in mind, you’re going to end up frustrated and disappointed. It’s important we talk more about these things before we arrive at making your diy heater.

Making sure you get the best use out of your heater

First and foremost, to get the best use out of your clay pot heater, you’ll want to be in fairly close proximity to it. And this is being said before taking the size of the space you’re trying to heat into consideration.

You might’ve seen the concept of a clay pot candle heater in the past and had the thought “a bunch of candles under a pot? What good’s that going to do as a heater?”. And your apprehension definitely isn’t misplaced!

For you poor souls that rely on radiators for heating inside houses with no central heating (I’m also part of this club), you’ll know what I mean when I say that although the radiators do manage to make a dent in the chilliness of a room, you really feel their effectiveness when you place yourself right beside them.

At one point in time, I even had this setup where I’d have a radiator sitting right next to me underneath my desk (it was a small one with wheels so it could be moved around). The heat would rise from the radiator, bounce off the underside of the desk and circulate in a cuboid fashion, keeping me warm. The rest of the room might’ve gone up a degree or two, but it was still pretty freezing.

So you might have caught on to what I’m alluding to here. There’s a misconception that building a clay pot heater is for the purpose of heating the whole room to a comfortable temperature. In most scenarios, this won’t be attainable.

The clay pot heater will serve you better as something that you can put your hands and feet close to to warm them up. And while that may seem kinda lame, don’t forget that you lose a significant amount of your body heat through your extremities (namely the feet and head).

People can’t agree on whether it’s effective

There’s a seemingly 50-50 split between those who vouch for the candle heater and others who claim it doesn’t work.

This is probably because the difference between a room where no difference is felt and one that is perceptibly warmer could be a few extra cubic feet of space or even an extra candle in the heater.

Another point to make is also on what you expect from the heater- you wouldn’t sleep with a hot water bottle outside of your bed and expect to be warm, that’d be unreasonable! So what it really comes down to is what your idea of success is in this context.

Great! Now that we’ve gotten that out of the way, we’re ready to look at how the candle heater is constructed.

Essentially, the heater is a bunch of candles with an inverted terracotta pot above them.

The purpose of the pot is to absorb and hold onto the heat produced by the candles, and the terracotta/clay accomplishes this pretty well. The stored heat then radiates from the flower pot. Should a bunch of candles be lit without the pot covering them, the heat generated would quickly disperse into the rest of the room.

We’ll be talking about the most basic type of flower pot heater first.

Step 1

You’ll need 4 main components:

• A terracotta flower pot
• A number of candles
• A base to put the candles on
• Something to elevate the pot

Place the candles on the base. Normally people use the saucer that comes with the pot as the base. If your pot didn’t come with one, substitute it with something similarly shaped that’s non-flammable. Optimally, your base will have raised edges to stop wax from pooling outside of the heater.

Step 2

You’ll need something to heighten the pot above the candles so as to create an intake for air. Commonly used are tiles stacked on one another, or bricks. You might be able to find a base that acts as the base as well as the method of elevation, such as a rectangular baking tin. You can now start lighting the candles.

Step 3

You can now finish off your heater by resting the flower pot on your method of elevation. It’ll gradually warm up and start to radiate heat.

Adding more pots to the flower pot heater

So we’ve just gone over the most barebones form of the pot heater. You’ll commonly find constructions where a second, smaller pot has been added to the mix.

To accommodate additional pots, you’ll need a threaded bolt, metal washers and nuts. These terracotta pots usually come with a hole at the bottom of them to let water out into the saucer (after talking about pots in the context of being heaters for this long, you’d almost forget they’re normally meant to house plants!). The bolt goes through the holes in the pots, and the pots are held in place by washers pinched with the nuts. If the hole happens to be smaller than the nut, you won’t need to use washers.

I can’t say having more pots in your heater is all that necessary. When your candles die out, a heater with more pots in it will stay hot for longer, but on the flip side, it also takes longer to heat up. The metal added in the form of the bolts, washers and nuts are purported to facilitate the transfer of heat from the flames to the pot, but any observable difference is negligible.

Other variations

Other variations of the clay pot candle heater include one where the whole heater is suspended above the ground by a chain or wire.

This eliminates the risk of having the surface you put the heater on getting damaged by the hot base. The fact that this design allows it to sway means you won’t need to worry about the heater sliding around and tipping over inside of a boat.

To convert your heater to this design is fairly simple- instead of a regular bolt, use an eye hook bolt. The eye hook allows you to thread whatever you want through it, and then you can hoist it up wherever. With this design, you’ll need to make sure the base is also held in place by the bolt.

Should you wish to feel more heat radiating from your heater, you can swap out your current pot for a smaller one, provided the rim of the pot still hangs over your candles.

So that’s pretty much how it goes! The system itself is very simple. There’s almost more to be said on what’s needed to achieve good results than building and operating it.

It has to be said that using a clay pot heater comes with its own set of hazards.

There are concerns you should familiarise yourself with before deciding how you’re going to use it. Always remember that this device uses not just one, but several open flames to operate. This is something you’ll want to keep a close eye on most of the time.

Toxic fumes with long term consequences

One of the more innocuous hazards is inhalation of candle fumes.

Most of the tea light candles you’ll find use paraffin wax as fuel. When burnt, the wax releases chemicals such as toluene and benzene, which can cause respiratory irritation and lung cancer respectively.

So with that in mind, I’d advise refraining from prolonged and repeated use of the clay pot heater unless absolutely necessary.

You might knock it over

The clay pot heater also relies mostly on gravity to hold itself together.

Pair that with having to be close to the heater in order for the heat to radiate onto you, and you have a recipe for accidentally knocking it over. Also make sure to keep materials that are flammable and can melt clear of the heater.

Not that the heat radiating off the pot will cause a fire, but let’s say you adjust your feet in the middle of the night, and the corner of your sleeping bag gets nudged into the air intake where the flames are. It won’t be pleasant.

A bigger flame than expected

A little bit more technical but definitely worth a mention is that the candles don’t act the same way in the heater as they would by themselves outside of it. What do I mean by this?

Well, under normal circumstances, when a candle is lit, the wick burns, the flame melts the paraffin wax, but just enough to get absorbed by the wick and continue burning. The rest of the wax stays solid. The wax has to melt before it can burn, and candle manufacturers add other ingredients into the wax so it stays solid and melts optimally.

So simply put, liquid wax = ready to burn, whilst solid wax = won’t burn.

Now let’s come back to the pot heater. The heat generated by the candles is now contained within the pot, which means the internal temperature of the flower pot heater gets pretty substantial after a while.

Should the temperature get too high, all the wax in the candles that was meant to gradually melt suddenly does so all in one go. Now you have a whole bunch of fuel sitting below an open flame.

Now imagine something unfortunate happens like the heater is bumped and all that melted wax jumps out of the candle tins. All that spilled fuel is extra surface area to accommodate a potentially big fire. So definitely make sure to adjust your heater so the internal temperature isn’t hot enough to melt all the wax.

A bucket of water won’t help things

The worst part is that if something does go awry and there’s a whole bunch of melted candle wax burning, you can’t just dump water on it.

If you do, you’re going to conjure up a sizeable fireball. Treat it how you would an oil fire (as liquid paraffin is a mineral oil), and make sure you have an extinguisher handy as a safety net.

So all in all, whether it’s worth it to build and use one of these heaters really depends on your situation and intent of use.

As a last ditch effort against completely freezing, sure. As a cheaper alternative to more standard forms of home heating, I’d say no (unless you’re 100% strapped for cash).

Open fires by nature carry more hazards with their operation, and on top of that, this particular heater is an improvised device.

The more consistently you use it, the more chances there are for something to go south.

Alternative methods of heating

It’s recommended that in order to stave off having to use a clay pot heater for as long as possible, you practice due diligence and stock up on enough propane (or whichever gas is relevant to you).

This form of fuel is a lot more versatile as you can use the same type of gas for many different appliances such as stoves, water heaters, generators (not all though) and of course space heaters.

What’s more, there are ultra-portable gas heaters that you can really take around with you anywhere. Propane canisters come in all sorts of sizes as well, so a section of your propane stockpile could be in the smaller 16-ounce variety as opposed to those big 20lb tanks.

Having one of these ultra-portable heaters will allow you to deploy them in the same fashion you would the homemade candle heater, but they are infinitely less likely to cause fires, they put out significantly more heat, and have dials you can adjust them with.

But as always, when using appliances that rely on gas, have a carbon monoxide monitor handy with indoor use.