“Heat an entire room for 8 pence a day!” says the title of a video making the rounds on social media. After watching the video, I could already see some problems with this claim. But the heater looked useful, so I decided to try it out, and see what it COULD do.

IMPORTANT… After additional review, we have concluded that there is NO CIRCUMSTANCE under which this system is not a SERIOUS fire risk.

But the original information is still available here.

The setup consists of a bread pan, two clay pots (one large, one small), and four tealights (an alternate has bricks and clay pots). The tealights are placed in the bread pan, and lit. The small clay pot is placed upsidedown over the tea lights, balanced on the edges of the bread pan. The larger pot is balanced in the same manner over the top of the first one.

The first problem I had, was with the design of the setup. It looked like a fire waiting to happen. Tea lights, in a bread pan, sitting on a magazine. Tea lights get hot when they burn down. Probably not hot enough to light a magazine on fire, but to me, a child raised in a home with wood heat and taught by her father to respect fire, too much of a risk.

So I purchased a clay pot tray, and turned it upsidedown for a fire-proof base. I had to improvise some of the other elements a little also, but the end result was equally efficient, with one major difference:

My setup held only three tealights, not four. It does not significantly change any of the aspects which I am reporting on – I did not try to heat a large space, and the number of candles does not affect any of the other numbers, since I used his original numbers as a baseline.

These are the problems I found with the system:

1. The room the Brit heats in the video is a VERY small room. It is also generally a fairly WARM room. So the amount of heat he required was fairly minor. A toaster oven used to heat his noon meal would have produced sufficient heat for an hour or two in a room that size. Just pointing that out, because “an entire room” in this case, wasn’t much at all. By comparison, we are talking about a bathroom, or a bedroom in a 1970s singlewide trailer (you know, those little bitty bedrooms).

2. He lists the price of tea lights at about 1 pence each. This converts to anywhere between 1 and 2 pennies USD, depending on the exchange rate. This price is found NOWHERE for tea lights. At least, nowhere I can access that actually ends up BEING that low a price by the time the costs are tallied. The lowest I found was 4 cents each. I paid 6 cents each for mine. While this is only pennies we are talking about, the cost doubles, or triples when the actual cost is calculated. That is very significant. His 8 pence a day now becomes 16 or 24 pence – or 32 to 48 cents.

3. He claims that the tealights burn for “about 4 hours”. This, again, is rather an exaggeration. Mine burned for 2 and a half hours. Perhaps tealights are larger in Britain, but I doubt it. Perhaps they are made of a different type of wax – but if it burns longer, it also burns cooler, so there is a trade-off. Since mine burned for just 2 1/2 hours, I have to base my calculations on that. Our costs just increased by 50% again, if we have to do three burns instead of two for the same heat. We are now up to 48 to 72 cents per day.

4. Some people with whom I discussed this suggested that “residual heat” in the clay pots would compensate some for the shorter burn times. The pots cooled fairly quickly, retaining radiant heat for only a short time, and being completely cooled within half an hour. This means that they’d only have useful residual heat for about 20 minutes. For the sake of simplicity, we’ll call the burn and heat time, combined, about 3 hours. We still have to do three burns for anywhere close to 8 hours of heat (based on his original concept of 8 hours equaling a day).

5. Because he only counts a day as 8 hours of heat, you still have 16 hours unaccounted for. To truly heat for a day, you’d have to again triple your cost. This brings the cost of heating a tiny room up to somewhere between $1.44, and $2.16 for an actual full day. Now, I realize people are NOT going to try to use this to heat a home, but we have to calculate it in that manner in order to see how it compares with other heat forms. If you can heat an entire 3 bedroom house for about $200 a month, in SEVERE cold (yes, we did so in Wyoming – an 1800 sq foot home), then it works out to about $6.66 per day to heat the whole house. The room in the video was about 8X12 ft, so that works out to about $.36 per day to heat that space using gas or electric, for a full 24 hour time period. Here, in the south where we live now, it is half that amount. For any amount of real heating, the tealight heater is simply NOT economical. I point that out, because his main claim is that it is cheap heat. It is not. It is actually very expensive heat.

So is this little thing good for anything? I originally thought so, but I don’t anymore.

1. Spot heating. When you need a little extra heat in a single area, for a short period of time – this kind of heating is ALWAYS more costly than whole house heat, on a square foot basis. What makes it economical is being able to heat just a single small area rather than having to increase the heat throughout the house. I was using mine to rapid-cure silicone. In the summer, our silicone for our Fermenta Cap products cures in about 4-5 hours. In the winter, even with the heat on in the house, it can take 24 hours, sometimes more, to cure. This slows our production to the point of getting us seriously behind in order fulfillment. I can pour my silicone, light three tealights in the burner, and have them cure on one burn. The burner puts out just enough extra heat in that one small area, to cure my silicone within 4-6 hours. MUCH faster. That is worth 18 cents per day to me! If I need to leave the house, and the burner has only been lit a while, I can blow it out, and place the clay pots over the tops of the silicone molds, where the residual heat works on them, safely, while I’m gone. PROBLEM was, I could not walk away, the heater created a Flash Fire, even with the pots raised higher.

2. A cozy alternative to a fireplace. The warmth of an open flame just has more romantic appeal on a cold winter evening. A candle powered heater, and a warm mug of hot chocolate, and a good story to read with the family could make any evening special. I’m not willing to try it for that though, if I am having to watch it to make sure it does not light a fire on the surface it is sitting on.

3. Emergency heat. It is likely that the heater would get hot enough on top to at least heat water, and in an emergency, a little heat is better than none. Because it is off-grid heat, it seems all you need is to be sure you have SOME ventilation if you light more than one, and be sure you have matches on hand. Unfortunately, you can’t leave it unattended, and the potential for too much fire is too great.

There are some safety issues if you decide to experiment with this type of heater – SERIOUS SAFETY ISSUES. The issue with heat from the bottom is only one potential issue. Since this is an open flame, standard cautions regarding candles and fires apply.

1. When you have tealights concentrated together, they create more heat than a single candle. The wax in each tin will quickly reach the melting point all the way through, since you have a covering over the lights that make the candles heat up more (there is NO published design for this heater type that does not concentrate the heat). Liquid wax will wick out over the edges of the tin, so that whatever surface you have them on can become covered in a thin film of melted wax. After a matter of half an hour or so, this is a SERIOUS fire hazard. Even when you take precautions, this gets out of control in ways it does not look like it would.

2. The clay pots need to be placed over the candles, and that concentrates the heat enough to create a Flash Fire even when they are placed fairly high. Since the wax becomes liquid fairly rapidly, a build-up of heat on the surface of the tealights can cause the entire surface to ignite – this happens when there is sufficient heat to maintain the fire without needing a wick. If this happens, you’ll hear the sound of the flames (a quiet roaring), and black smoke will billow out of the hole in the pots, and around the edges – the fire is NOT the only problem, in this case the smoke is also a serious risk. If wax has wicked out onto other surfaces (which often happens), it is an even greater fire hazard, PLUS it produces so much smoke that the smoke alone could be deadly. The fire is also very difficult to put out  – you’ll need to find a way to smother all of the candles at once or they’ll re-ignite, and you can’t blow this out! If you decide to test this, BE VERY CAREFUL, and make sure you have some means of smothering the entire surface of all of the candles at once, or you cannot put out a flash fire. It can, and WILL end with a house fire if you are not careful.

3. To generate additional heat, some people close the hole in the smaller pot. The greatest heat build-up is right at the top of that smallest pot, and it can be far hotter than you think. If you plug the hole, the material you use to plug it has to be entirely fireproof.

4. Make sure you have hot mitts close by, in case you need to blow out the heater. You have to remove the pots – you’ll need a safe place to set them also.

5. Keep it away from kids and pets if you are experimenting. This thing gets HOT on the surface. It is designed to trap and radiate heat, and it does just that. It will get blisteringly hot on the surface of those pots, and if it creates a Flash Fire, it is even hotter. If you don’t like such risks in your home, don’t use this kind of heater.

My conclusion is that the video circulating is inaccurate, and even dangerous. While the concept could be useful, I cannot find any situation under which I feel comfortable with the fire risks involved.

I do not feel these can be useful in a power outage for any kind of significant heat either, because you can’t leave them unattended.

I just don’t NEED my room to be THAT HOT!