A Homemade Heater That May Save You Money

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Space heaters are great for heating and the best models are very safe to use and highly reliable, but there has to be a way to get cheaper heating. Many standard model electric space heaters will run up to 1,500 watts, which can be costly if you’re heating your room for hours each day. Perhaps there’s a way to rig up a homemade heater to save some money at home or at the office.

To figure this out, we’ll have to follow Matt Damon’s lead and “science the [expletive] out of this” as his character, Mark Watney, did in the 2015 science fiction film The Martian. Adapted from a novel by Andy Weir, The Martian finds Watney, a NASA astronaut, separated from his crew during a powerful storm and left stranded on Mars while the rest of his crew barely manages to escape. Watney now faces three challenges: 1) Grow enough food to last several years before he can be rescued, 2) Make contact with NASA, and 3) Make the long distance trip from his Ares III campsite to the Ares IV landing site so he can rendezvous with the next crew when they arrive.

The Martian, Matt Damon, Mars, NASA, Andy WeirWatney pulls off the first two objectives just fine, but it’s a long trip he’s going to have to make across Mars and he’ll likely freeze to death in his rover. The NASA rover does have a heater, but Watney drastically decreases his range by using it, which means he’ll get stranded during the middle of his trip and then freeze to death. So, much like us, Watney needs a heat source and digs up a Radioisotope Thermoelectric Generator (RTG), which is a big container of radioactive material that generates heat and energy. Watney has now solved his heating problem by strapping the RTG into the seat next to him so he doesn’t freeze to death during his Mars road trip.

If you had an RTG, you could probably do the same if you don’t mind running the potential risk of irradiating yourself, but it’s not like I haven’t done that enough with my old mobile phone. If you don’t have a chunk of radioactive material to provide you heat, here are two do-it-yourself ideas to make a homemade heater. All of the items needed can be purchased cheaply or be found around the house. These homemade heaters are probably just as dangerous as Watney’s RTG solution, but they have been proven to get the job done with variable results.

Emergency Alcohol Can Heater

This is the simplest of the three homemade heaters and is probably something Bear Grylls would create on an episode of Man vs. Wild or his current survivalist series Running Wild with Bear Grylls.

Items Needed

  • Empty 1-quart metal paint can with lid (or any clean can, preferably with a lid)
  • Roll of cheap, single-ply toilet paper (unscented)
  • Large bottle of unscented 70%-90% isopropyl alcohol (typically rubbing alcohol)
  • Matches or a lighter (with something to burn)

isopropyl alcoholpaint can

Step One: TP the Can

  1. Get the toilet paper out of its packaging and remove the inner cardboard tube without unwrapping the toilet paper.
    1. If you’re having trouble, it might help to flatten the roll and get the cardboard tube bent and dislodged from the toilet paper.
  2. Once you’ve gotten the cardboard out of the toilet paper, squeeze the roll into the empty quart metal can.
    1. Make sure your can is clean and free of any labels or tags in the interior and exterior of the can. This is to further reduce the chances of something catching fire.

Step Two: Drown Your TP’s Sorrows in Alcohol

  1. With the toilet paper roll now in the can, pour in the isopropyl alcohol slowly to allow the toilet paper to soak up all of the alcohol.
    1. 90% or higher will burn hotter, but it also burns dirtier. 70% gives off a good amount of heat with a much cleaner burn.

Step Three: Burn It Down!

  1. Carefully set your filled can onto a secure, level surface that won’t be damaged or burned by heat.
  2. Light a match and drop it into the can to ignite the fire.
    1. If you have a lighter, it’ll be safer to light the end of a piece of paper and drop that into the can.
  3. To put out the fire, place the paint can lid over the can opening. You can also probably blow it out like a barbarian.
  4. If need to add more alcohol to keep the fire going, make sure you put out the fire first instead of dumping more alcohol into an active fire.

Once the fire is started, you’ll notice that you’ve got a pretty good flame going for a few hours. You’ll probably also notice that the toilet paper is not burning because the flame is only consuming the alcohol and the surrounding oxygen. The 90% isopropyl alcohol might singe the top of the toilet paper, but, for the most part, the TP won’t be burned and can be reused as a wick for this homemade heater.

A quick Google search has found that 99% isopropyl alcohol will put out about 13,000 BTUs per pound. One quart equals 32 ounces, which equals two pounds. So, if you’ve your toilet paper soaked up a quart of 99% isopropyl alcohol, the can heater is producing about 26,000 BTUs.

Will This Homemade Heater Kill Me?

It’s 2015 going on 2016. Anything is possible. Since you are dealing with an open flame, using the Alcohol Can Heater indoor isn’t very practical or safe unless it’s an emergency situation.

If you’re using the can heater to warm up a small room, you won’t run a big risk of carbon monoxide by burning rubbing alcohol, but it wouldn’t hurt to crack a window or invest in a carbon monoxide detector. Other than that, just keep it away from curtains, clothes, walls, and shelves.

Terra Cotta Pot Candle Heater

There are a few ways to create this heater, which requires a few more materials, but it’s a little safer to use. Here, we’ll look at the most basic design for a terra cotta pot candle heater.

Items Needed

  • Large Terra Cotta flower pot (unglazed)
  • Small Terra Cotta flower pot (unglazed)
  • Tea light candles
  • Loaf pan (or a flat, heat-resistant container)
  • Two bricks (optional)
  • Small piece of foil (or metal)
  • Matches (or a lighter)

ikea tea candlesterra cotta pot

Step One: Tea Lights

  1. Place the tea lights into the loaf pan and light them with your matches. Two to four is a good start, but more tea candles will put off more heat.
    1. If you are using a heat-resistant container, place bricks on two opposite sides of the candles to create an elevated surface.

Step Two: Pots Within Pots

  1. Place the small terra cotta facing down directly over the candles and leave it sitting on top of the loaf pan.
    1. If you’re using bricks, leave the pot sitting on top of the bricks.
  2. Cover the small opening on the bottom of the small terra cotta pot with the piece of foil or a small, flat piece of metal. Make sure the small bottom opening is well plugged.
  3. Place the larger terra cotta pot over the smaller pot and leave it on top of the pan or the bricks.

The idea behind this flower pot tea candle heater is to heat the smaller pot, which tries to store as much heat energy as it can to warm the air between the two pots. The warm air becomes less dense and rises up out of the of pot heater to displace the cold air in the room. The cold air is pushed down and is warmed up by the pot heater to create a convection current.

Your standard tea light candle contains about 13 grams of paraffin wax with about 547 kJ. Multiplying 547 kJ by .277 watt-hours per kJ gives us about 152 watt hours. From here, we divide by the 4 hour average lifespan of a tea light to get 38 watts per candle. To match a 1,500 watt space heater, you’d need about 40 tea light candles.

As for BTUs, one watt is equal to 3.412 BTUs. So, the 38 watts of a candle multiplied by 3.412 comes out to about 130 BTUs.

Will This Homemade Heater Kill Me?

While it’s definitely safer to use than the can heater, it’s not without its flaws. The inner terra cotta pot will get very hot while the outer pot will get between very warm to hot. Either way, it’s not something you want to have children or pets around.

The use of a loaf pan or bricks also doesn’t look very appealing nor is it completely stable. If your candle and pot set up isn’t out of the way, you’ll likely bump into it and knock the pots over of tip the candles out of the pan.

Just like the can heater, you likely won’t have an issue with fumes, but you should open a window a tiny bit just to be on the safe side.

Too Long, Didn’t Read

Building a homemade heater is a good way to supplement your heat, but it’s not the best way to solve your heating problem. For the alcohol can heater and the terra cotta pot heater, they will warm up a room to a certain extent, but they won’t provide reliable high heat output. You’d have to use a bigger can and more alcohol or more pots and candles to increase the heat, which may require a little more venting. Electric space heaters do offer reliable and higher heat output, as well added safety measures (depending on the type of heater you’re buying).

Alcohol TP Can Terra Cotta Candles NewAir AH-400
Watts NA 38 per candle 400
BTUs 13,000 per LB (99%) 130 per candle 1,365
Venting Somewhat Somewhat Nope
Heat Type Radiant Convection Convection, Radiant
Open Flame Yes Yes No
Hot to Touch Yes Yes Yes

There are a lot of different model heaters that range in wattage usage and BTU output that should be considered while you regrow your eyebrows after making an alcohol can heater. The NewAir AH-400 Low Watt Oil Filled Underdesk Heater, for instance, uses 400 watts and produces 1,365 BTUs to about 40 square feet. That’s comparable to the alcohol can and terra cotta pot heaters in coverage and it won’t run up your energy bill as high as a 1,500 watt space heater.

The AH-400 will also warm up much quicker than those homemade heaters, which take 30 to 60 minutes to warm up the room a few degrees. Homemade heaters won’t allow you to walk around in your underwear during the winter, but it will take the edge off a bit during cold nights.

newair, ah-400
“Come with me to a warmer paradise.”

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