There are one too many videos and articles on the internet discussing the idea of an upside-down flowerpot space heater. Sounds like magic, right!? And if it worked as well as many companies advertise it, I’m sure more people would catch on to the idea. Don’t let this discourage you, however.
Can a candle heat up a room?
The terra cotta candle heater works well to curb the chill in your home but it will not heat a room in its entirety. There are great benefits to the candle heater but let’s be real, this is not the winter cure-all.
There are many influencing factors, of course, that can determine its effectiveness for your home, such as the size of the room, the blinds or curtains, the exterior temperature, and your home's insulation.
If you keep your hands and feet close to it, you will feel it’s warming benefits at a fraction of the cost of a typical heater.
This is a cheap and ingenious DIY project anyone can make. More importantly, it can help cut down on the gas and electricity bill every winter and in my home efficiency, practicality and frugality are key.
Follow the outlined steps and pictures below to build one of these for your home.
What is the science behind heating a room with a candle and a flower pot?
A candle will generate a small amount of heat and light while it burns. This heat, even if minimal, can be used to our advantage during times of extreme cold or a power outage.
Heat generated from an uncovered candle is generally dispersed among a room, absorbed by the walls and furniture and lost through the doors and windows. The terra cotta pot works effectively to absorb and maintain all this heat centralized. When the pot has reached a high temperature, it will radiate the heat enough to be felt if you’re sitting nearby. In scientific terms, the heat absorbed by the pot is transferred to the room via convection, whereas it is transferred via conduction if no pot is used.
The pot will stay warm for a while, even after the candle dies out- the time will depend on the temperature of the room. When the temperature of the pot has decreased and is no longer radiating heat, you can place your hands or feet against it for some warmth (Caution: don’t burn yourself!).
The key here is remembering that you get what you put in. What this means is that if you put three cheap tea light candles, it will take a long time for your pot to heat up and radiate that heat. Instead, if you use a bigger candle, a sterno, or better yet make your own natural candle, the flame will be much bigger and you’ll feel the benefits of your heater much quicker.
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Is the tea light flower pot heater more efficient than just tea lights?
This question depends on what the user intent is for the tea lights. If the goal is to create a centralized heat source while burning candles then essentially yes, the flower pot is a much more effective option. Although tea lights produce a very small amount of heat, any heat that is produced is typically lost in the air (unless trapped). In the case of a terra cotta flower pot, the heat is trapped and contained within the pot.
During a power outage, this flower pot warming system can work as a light while creating a basic heating source. In a situation where the room is cold and dark, the pot is a better option than just a bunch of tea lights burning on your coffee table. The pot is not a magical energy-producer or heat enhancer, however in this scenario it works as a tool to effectively absorb and contain heat while slowly radiating that heat outward.
If you’re desperately cold, you can wrap your hands or feet around the pot (again, use caution!) and at least feel your extremities regaining warmth and movement.
What risks are involved in using a candle heater?
FIRE: A huge mistake is leaving these heaters on overnight. Any open flame is risky and we must keep our eyes on it. Never leave the house while the candle heater is going. Make sure you place the heater over a safe non-combustible and sturdy surface, such as a tile floor or cement hardy backer. Do not place it over or near paper, magazines, carpet, walls, flammable materials or any unstable surface.
Take all necessary precautions to maintain your safety because a flame can cause a fire in an instant. It’s recommended that you keep a fire extinguisher nearby (and make sure you learn how to use the extinguisher prior to building this heater).
Note: There have been numerous reports of people almost catching their homes and boats on fire because the tea light candles were placed too close to each other. The problem was that the thin aluminum that holds the tea lights melted and the paraffin leaked out, thus creating a big fire hazard.
GAS LEAK: If your house has been hit by an earthquake, tornado or other emergency, you must thoroughly check to make sure there are no gas leaks present. If there are, do not light a candle or spark a flame.
CARBON MONOXIDE POISONING: If your heater is enclosed in a small room or inside a tent with no ventilation (such as open windows), you run the risk of carbon monoxide poisoning. If the room you’re in is large, it would take a lot more candles to produce enough carbon monoxide to kill you but it’s always better to be safe than sorry, so follow these tips.
- Keep the area ventilated: Whether you’re trying this heater out in your camper van, tent, or living room, make sure there’s a constant flow of air. Crack open a window to allow carbon monoxide to escape and fresh air to enter.
- Install a carbon monoxide detector: If you’re trying this out inside any closed structure (for example, a room, office, garage) make sure you have a detector installed, just like you would a fire detector. Carbon monoxide is dubbed the “silent killer” because it’s colorless, odorless, tasteless and non-irritating so a detector is highly recommended regardless.
TOXIC FUMES FROM CANDLES: The fact that you’re considering a candle-based heater gives me the feeling that you’re okay with burning candles around the house. There’s a lot of debate on whether or not burning a candle releases toxic fumes and the potential side effects associated with candle soot. Candles are typically made of food-grade candle wax, which has been approved by the FDA for eating. But do you think everything the FDA approves is good for you? If so, let me remind you that the FDA also approves the use of Red Dye 40 which is a chemical compound made from petroleum known to cause hyperactivity and allergies in children and is also linked to cancer. I think I’ve made my point on the FDA so let’s get back on topic.
If you’re nervous about inhaling toxic fumes from candles, do some research and find the answers you need. There are many types of candles you can choose from: paraffin, soy wax, palm wax, beeswax, lard, gels and vegetable-based waxes. Continue reading to see how I made my own candle using vegetable shortening!
A HAZARD FOR CHILDREN AND PETS: Anyone can risk getting burned or injured with this heater. The clay pots can withstand temperatures of over 500 degrees Fahrenheit. It’s very unlikely that your pot will reach this temperature with candles but it’s common for it to reach up to 200 degrees F. In any case, make sure you place the heater in a safe location away from children and pets. The heater we demonstrate below has a built in hook and handle to make it safe and easy to move while it’s hot.
The essentials needed to make a DIY candle heater
For the pot structure you will need:
- 1 large terra cotta pot (the size is up to you, so long that it’s large enough to cover a a sterno or medium candle)
- 1 smaller terra cotta pot (the size is up to you, so long that this one fits inside the large one)
- 1 small terra cotta plate (the size that is fit for the smaller of the pots you chose)
- 3 pavers or bricks
- 2 small washers (I used round washers)
- 2 large washers (I used square washers)
- 2 toggle bolts (including the screw rod that comes with it)
- 1 open eye hook
- 1 piece of wood (I used a piece of an old broomstick)
- 1 plant hook
For the candle you will need:
- 1 medium empty tin can
- 1 container of vegetable shortening
- 3 candle wicks, or
- a small piece of cloth, or
- a small piece of insulation / fiberglass
- 1 spatula
These are items I found in my garage but you are free to use your creativity here. If you don’t have square washers like the ones we used, you can use large round washers too. If you don’t have candle wicks, use insulation, cotton or fabric to make a homemade wick.
Some people use three pots instead of two. You can experiment with three, even though there may not be a huge noticeable difference than when using just two pots.
The method: Let’s build this heater!
Gather the following items and place them in the order shown below.
Assemble everything starting from left to right, beginning with the screw rod. Insert the round washer first, followed by the square washer.
Push this through the inside of the small clay pot.
On the other side (the outside of the pot) attach the toggle bolt, as shown below.
Gather the next items as shown in the image below.
Notice that another toggle bolt was added to the screw bolt in the opposite direction. A gap of about 1 1/2 inches was left. This gap is intended to create enough space in the rod to attach the rest of the components. It can be adjusted as necessary.
Place the large pot over the small pot and allow the screw rod to peek through the hole of the large pot. Then, stack first the large washer and the small washer above it.
Top it off with the plant hook. Make sure the hook is tightened firmly.
Next, drill a pilot hole in the broom stick and screw in the open eye hook. This will become the handle to move the clay pot assembly safely.
The whole ensemble should look like this:
Finally, install the pavers in a triangular shape leaving gaps in between each to allow air flow. Placing a clay plate in the center will create a safe surface for your candle to burn. Allow enough space in the front to insert and remove the candle when necessary. If you want, add a fourth paver in the front to contain the heat while the candle is lit (this is optional).
The top view should look like this (with the candle in the middle):
Let’s make the candle
Gather all the items shown in the image below.
Use a spatula to fill the can with vegetable shortening. With a stick, create a hole in the middle (if using 3 wicks, create 3 holes that are evenly spaced).
Insert the wick of your choice all the way to the bottom of the tin can.
Note that as the candle melts, the wick will fall over because the shortening becomes liquid and there’s no consistency to hold it. You can prevent this by making a “wick holder” out of a metal wire that is loosely coiled around the wick. This step isn’t shown here but it works. This candle should last more than three hours.
Another thing to note is the flame that is produced by each kind of wick.
A candle wick will produce a small yellow flame, therefore it will take longer for your pots to heat up.
A cloth and fiberglass wick has to be saturated in shortening before lighting, otherwise it will not catch on. These two provide a thicker flame and will heat up the pots rather quickly.
Keep in mind that any candle will produce soot to some degree. To reduce the amount of soot, trim down the wick periodically.
Now a days, many homes are built with efficient central heating systems but in the event of a winter power outage, which is not too uncommon, our heating system will be of no use and we’ll have to resort to using blankets and extra layers of clothing.
Making a terra cotta space heater is a smart way to back yourself up in these kind of emergencies. It’s also an environmentally friendly method to warm up small spaces without needing to heat up all the unused rooms in a house. While it’s not as effective as a fireplace, this viable heat source can at least break the chill in a room while warming up your extremities (hands and feet) during extremely cold winters.
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It helps in emergency situations to close unused rooms and lay blankets on the floor. So much cold air comes in from the floor. Put up a tent in the largest room. Hang blankets on the walls. That’s why castles had tapestries a few inches from the wall to keep the cold out as much as possible. This heater would easily warm a tent.
Those are great tips!! Thank you so much for sharing!
My question is, why use nested pots instead of just a single pot? It would get hot but more effectively and quickly provide heat since you wouldn’t need to wait for the outer pot to warm up enough to start working.
That was what I was wondering too. If I was doing this I would just put the candle or can of lard in the pot that is setting up the right way then invert another smaller pot on top of that one so it would go inside of the first pot. I think that the 2 pots would heat up just fine, also the heat would escape thru the hole of the pot you may be able to heat a pot of food, water or coffee. This did get us to thinking what we would do ….haha
Space heaters that utilize liquid or gaseous fuel are also an option. These types of heaters are a great way to save on your heating bill. The best thing about these types of heaters is that they are very efficient and do not store any heat.
Talk to us about where remade terra costa’s can be found along with mentioned space heaters.We have tremendous power outages during the winter.
I tried this! Not as effective as I was hoping it would be..but better than nothing.
Hi Brad, Thank you for trying it out. Great way to find out what works and what doesn’t, so when the SHTF we can be accurate with our practices.
We understand that this will work only for some and to a certain extent. Specifically dependent on the room size, the ceiling height, how many windows you have in the room, how well the building is insulated and the exterior temperature and wind factor. Keep up the good work in emergency preparedness.
I see this sort of thing as a useful tool for (cold weather) camping to use to heat the interior of a tent, or to keep in your car or truck in case you get stuck in a blizzard/freezing weather – to keep you warm inside your vehicle instead of having to run your engine constantly. Sure, you could also use a few of these in a room of your home in a prolonged power outage during cold weather (if you don’t have a fireplace/stove). These things are quite effective in smaller enclosed spaces (a tent, or under a tarp/blanket in an outdoors emergency situation). Just include the makings for this in your vehicle, along with a blanket, as part of your emergency kit.
Great article. I made one of those about 6 years ago from instructions on the internet. The design was inferior to this design, so I am going to give it another try with these instructions. Thank you!
Thank you! Please let us know how it goes for you!