Power Consumption

• It takes quite a bit of energy to turn electricity into heat. The U.S. Department of Energy points out that operating one is even more expensive than a combustion space heater that runs on kerosene or another kind of fuel. A portable heater (according to the DoE) can consume between 750 and 1,000 watts. That's as much as a coffee maker or toaster oven, and those aren't appliances you keep on for long periods of time, as you would a space heater.
  
  

Cost

• One way to decide whether or not to use a space heater is to calculate the cost of operation. The Department of Energy tells you how to do this. Simply find the wattage of your space heater on the box or in the user manual. Multiply this by the number of hours you will use it, and divide that number by 1,000. Then, multiply this figure by the kilowatt-hour rate charged by your utility company, and you will know how much that space heater is costing you.
  
  

Efficiency

• Space heaters, as Gary Foreman points out at The Frugal Life, are considered 100 percent efficient because all of the energy they emit goes into the room they are heating. Standard furnaces lose a lot of heat through the ductwork running through your home. That increases the value of your space heater and makes operating one more likely to be worthwhile.
  
  

Advantage

• One great advantage of electric space heaters, according to the Department of Energy, is that they don't require you to vent any gas. A kerosene space heater, on the other hand, emits carbon dioxide and other gases you really don't want in your living space.
  
  

Proper Use

• If you're going to use an electric heater, it's best to use it sparingly and in an enclosed room, as it will cost more to heat up a larger room. Further, you should keep the heater on only when you are in the room and can enjoy the heat. This is also a safety concern; electric heaters can cause fires if something goes wrong.