Electric resistance space heaters are a good energy-conservation strategy if they allow homeowners to heat their homes to a lower temperature with their central heating system. For example, many people only heat their homes to 55 or 60 degrees and use space heaters to heat the room they’re currently occupying or to heat the people directly. Many recent advertisements tout specific electric resistance space heaters as being superior to others. This article explains the operation of the two general types of electric space heaters and discusses advantages and disadvantages of these different types.
Electric space heaters are all around 100 percent efficient at converting electricity into heat. Electric space heaters come in two types: convective and radiant. The convective are designed to heat the air in a single room. Radiant space heaters, many advertised units with quartz elements, don’t heat the air directly but instead heat people and objects in a room with radiant heat. Radiant heaters are excellent for heating the portion of a room that you are using while working, watching TV etc. Convective space heaters excel at heating a whole room where you and others may be moving around, the kitchen for example.
Radiant space heaters may save energy compared to convective heaters if you remain in one place and you merely need a heater to keep you warm. However, radiant heaters can heat one side of you while the other side remains cold. Experiment with positioning the radiant heater to heat the objects around you like your desk, chair, and wall. This strategy makes the radiant heat come toward you from multiple directions.
The temperature of the heating elements affects comfort too. The hotter the elements, the more likely you won’t be comfortable. Hot radiant elements create the warm-side / cold-side problem. Hot electric convective elements create air stratification with cold air at the floor and warm air at the ceiling. Convectors with fans heat faster but convectors without fans may create better comfort.
Electric space heaters have thermostats that are usually just a knob with numbered settings or hi-lo settings. The trick to setting the space heater’s thermostat is to notice the point at which you’re minimally comfortable and turn the thermostat down just to the point where the heater cycles off. After that the heater cycles on and off automatically and maintains the comfort level you selected.
See The Homeowners Handbook to Energy Efficiency or Residential Energy: Cost Savings and Comfort for Existing BuildingsChapter 6 for more information. For professional information about heating systems and energy efficiency see Saturn Hydronic Systems Field Guide.