Electric Resistance Heaters
Electric resistance heat works by directly converting electric current into heat. Virtually all of the energy in the electricity ends up as usable heat, but this system is still pretty inefficient when you consider the inefficiency of electric generation and additional losses during transmission.
Electric resistance heat is usually the most expensive form of heat and is not recommended very much anymore except in special situations. Because electric resistance heating equipment is often the least expensive heating equipment, it tends to be popular where first cost is an issue, but operating costs are not.
This is true when heating is rarely needed. One example of this is heating for a second home that is infrequently used, or when the person who is having the equipment installed is not the one who will pay the utility bills, which is commonly the case with rental properties and spec buildings (ones built for resale as opposed to owners building something they plan to occupy themselves).
Resistance heat uses a metal element to convert electricity into heat. This element has a high "resistance" to the passage of electricity, and when it is forced to conduct electricity, it heats up in the same way a light bulb filament heats when an electric current passes through it.
Heat produced by electric resistance units can be distributed to, and throughout, the living areas of the home in a number of ways. Perhaps the simplest method of distribution is to locate the resistance heating elements themselves within the room to be heated. Units can be installed on a baseboard, wall, or can be portable.
The resistance element heats the air around it (which then becomes warmer and less dense) and thus rises, creating a convection current, which carries the heated air away and circulates colder air to the unit.