The energy efficiency of electric baseboard heaters depends on the model and age of the appliance. Energy efficiency is defined as using less energy to provide a service compared to another provider of the same service.
Older models of electric baseboard heaters are not as energy-efficient as newer models. New electric baseboard heaters can heat between 50 to 200 square feet of space while using 500 to 2,000 watts of power. Electric baseboard heaters are available in both 120 and 240 volts.
According to Energy.gov, the most energy efficient baseboard heaters are electric resistance heaters. All of the incoming electric energy is converted to heat. Thermostats located in each room control the baseboard heaters as they are designed for zone heating.
Electric heating elements within the heaters warm up the air inside the casing. Aluminum fins help transfer the heat into the room. As the warm air rises, cool air is drawn into the heater, continuing the cycle.
One aspect that affects energy efficiency in electric baseboard heaters is the fact that coal, gas or oil generators provide the electricity. Only about 30 percent of the fuel's energy is converted into electricity. Therefore, heaters that use lower wattage for larger spaces are preferable.
Sometimes less expensive models of electric baseboard heaters do not function well. They are noisy and less energy-efficient. Energy.gov recommends looking for heaters with labels from Underwriter's Laboratories (UL) or the National Electrical Manufacturer's Association (NEMA).