How to heat a medium-sized room more efficiently in winter time without pay too much for electricity?

I've already insulated my window and door by using some weather seal strips.

So my first guess was to use the tea candles or some heating system in which tea candles heat a combination of ceramic flower pots, but according to some article, they're too impractical (not to mention the indoor air pollution issue).

heating system in which tea candles heat a combination of ceramic flower pots

I also tried some "energy smart" fan heaters, but by using 1-2kW of power it looks like my kettle is doing a better job by using the same amount of power and at least by boiling the water.

I was thinking to give a try to solar concentrator placed outside my window and focused to my indoor (aka "Death Ray"), but 2800°C is definitely too hot for me:) I don't know if anyone tried to built something similar, but simply for heating the room or you know any other life hacks.

  • All energy ends up as heat. What other sources of energy do you have? Do you have a working fireplace? A gas supply? Is your question about efficiency or cost? Electricity is just about 100% efficient at heating (see first sentence). Anything else less so. Solar heating only works when the sun is shining - not much use where I live !
    – Dave45
    Commented Jan 22, 2015 at 22:42
  • @Dave45 No gas or working fireplace, just electricity. But it's always possible to buy a standalone gas bottle.
    – kenorb
    Commented Jan 23, 2015 at 10:31
  • Unflued/unventilated gas bottles indoors are generally not a good idea - water and carbon dioxide normally, but carbon monoxide is possible if the burners are faulty. Ok for draughty warehouses I guess.
    – Dave45
    Commented Jan 24, 2015 at 11:25
  • Here is the interesting link (posted by Phlume, but the answer got removed as too short), just in case somebody would like to elaborate on it more.
    – kenorb
    Commented Sep 30, 2015 at 19:10
  • 1
    In addition to the steps you have already taken to insulate your windows, you could buy some cheap plastic sheeting and tape it up over the windows. This will put one more layer between you and outside as well as (hopefully) stop any drafts that may still be coming in through them
    – Coder-guy
    Commented Oct 5, 2015 at 13:19

6 Answers 6


You basically has three options: heating, reducing area to be heated, and better insulation. Outside of this, there are no lifehacks ever going to save you, so let us tackle each one.


The most common heat sources are wood, gas and electricity. Electricity is by far the most efficient way in terms of heat produced. To reduce electricity usage, do use a heater directly instead of indirect heat through a refrigerator, lights, or other electrical equipment. They might have other benefits, but the heat value will be reduced as compared to a proper heater.

Gas can be a good alternative, but requires enough ventialation not to be a safety hazard. However there does exist good gas ovens, which are allowed for indoor use, and if you have the money you can invest in dedicated gas ovens for indoor use.

Wood is also a good alternative, and can be very useful and cheap if you have a good supply. This does however require a working fireplace, which the OP in this case says is not available.

Reduce area to be heated

If you have limited heating capabilities, it is always an option to reduce the are which needs to be heated. In one apartment I rented, I chose to close off two rooms in the winter, to reduce the electricity needed for heating.

Either close off rooms for the cold seasons, or accept that some of the rooms are going to be colder. You can also try to divide existing rooms using either light walls, or blankets in a pinch, which will help a little.

A variant of reducing area to be heated, is to allow the room to be colder, but use more and better clothes. This allows for you not to freeze, whilst the overall temperature in the room is lower. This can also be accomplished by using blankets when seated, or possibly a mattres heater when in bed.

Better insulation

Your best option is usually to get better insulation. Insulate walls, roof, floor and windows. Try to locate the coldest surface, and start there when insulating.

Note that adding blankets/rugs can help insulate both walls and floors. If you have really old windows, it can help with thicker curtains or if really cold by inserting extra windows or even insulation boards.

On a lighter note: A person usually generates around 100 W of heat, so inviting a lot of friends over will increase the temperature quite fast!


CAUTION: Some of the suggested answers seem dangerous. Open flames indoors are a terrible idea because of fire hazard and potential of carbon monoxide poisoning and oxygen depletion.

The hackability here is significantly limited by the basic physics. The total energy required to warm up a room is dependent on two things and two things only:

  1. Temperature difference between the room and the adjacent "cold" areas
  2. Isolation between the room and adjacent cold areas

Where the energy comes from and how it's getting introduced in the room makes little difference. A 300W open fridge or a 300W light bulb or a gas burner with 300W effective power do exactly the same thing.

If you want to more efficient, you can reduce the area that needs heating, lower the temperature in the heated area and/or improve insulation.

Other than that it comes down to which heating method provides the most energy per dollar. You can look at energy content here http://www.engineeringtoolbox.com/energy-content-d_868.html. For example the energy content of one kilowatt hour of electricity is roughly equivalent to 3 cubic feet of natural gas. You can use this to compare prices.

There are a few second order effects, like the exact heat distribution in the room or the losses involved in the heat generation but they typically don't make much of a difference.


I have a 1500 square foot cabin with Vaulted ceilings and a loft. The Fireplace is helpful, but when the fire goes out, it gets cold and fast. The thing that has helped me most is realizing 2 things: Anything can be a heat source. I have a million candles, most of them picked up cheap, then re-melted and put into metal bowls. Of course safety is paramount, so they are strategically placed and sit on River Rock. Fire-Metal-rock all seem to retain a lot of heat, and Yes, I did a lot of experimenting with Reflector Pans as well, cheap covered dish stuff from the grocery. I rarely have to turn on a light as well.

That Being Said, Most Importantly, I have a 3 1/2 ft crawl space under the house. After I put thick plastic black trash bags cut to cover the ground, I put in insulation against the floor with a staple gun. I should have used landscaping plastic instead of Duct Tape and trash bags, but there is a 100% change regarding the Hardwood floor. No more house shoes or thick socks.

I like the alcohol/paint can idea as well. I do wonder if Paint Cans are thick enough. Worth a try.

Sounds like a bunch of dudes with dude answers, we all have a little pyro in us.


Something similar to your tea candles solution would be toilet paper roll, rubbing alcohol and an empty paint can (as explained here). I actually saw this method in a video some time ago, but can't find it anymore.

enter image description here

Steps to take, to make above mentioned things into a heater and even a stove:

  1. remove the cardboard tube from the toilet paper roll

    1.1 you can either cut the cardboard with a scissor or peel the cardboard where it's stuck together, like this young man explains, and then pull it out.

  2. squeeze the toilet paper into an empty paint can (you can also use two toilet paper rolls, if your paint can is big)
  3. fill the paint can to about 4/5 with rubbing alcohol
  4. light up the toilet paper

The toilet paper functions as a wick, so all the rubbing alcohol will be burnt. Also the paint can will stay cool in the lower half, so you're still able to move it around.


To turn your heater into a stove, simply place three bigger paint cans (or any other heat-proof objects) around your heater. Now you can put a Pot on top and you're ready to go!


In my university dorms the students were forbidden to use electrical heaters ostensibly for safety reasons. The dorms did have hot-water heaters but they were barely sufficient. We tried using old computers, vacuum-tube televisions, etc. but the device which really warmed the room best was a complete surprise.

By leaving the refrigerator door open and moving it to the center of the room, the room would heat up comfortably and would stay warm. No other method of heating the room even came close.

For completeness of this answer, if you live in a damp environment then a dehumidifier provides >100% electrical efficiency in heating its surroundings.

  • 1
    I like the dehumidifier idea, but I can't believe the refigerator trick... if the fridge has a 300watt compressor - that's all the energy input to the room. It won't be as good as a 1kW or 2kW heater
    – Dave45
    Commented Jan 23, 2015 at 10:46
  • @Dave45: As stated in the answer, we were forbidden from using electric heat.
    – dotancohen
    Commented Jan 23, 2015 at 11:04
  • @dotancohen still, you would be better playing a lan party than using refrigerator. Commented Mar 10, 2016 at 11:03
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    @TomášZato: Sex would probably heat the place better than a lan party, in fact, well, let's just leave that option unexplored for purposes of LH.SE...
    – dotancohen
    Commented Mar 10, 2016 at 11:42

In greenhouses it is common to use black water-filled containers to absorb heat from the sun in the daytime and re-radiate it at night. If you are after a solar solution and have the sunlight it might be possible. Alternatively - is your hot water fixed-price/included?

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