Gas heaters are generally cheaper to use than electric due to the inefficiencies of electric heating, but they require a gas source and a vent to the outdoors, which can be inconvenient. Electric space heaters are more portable and can be moved from place to place to provide spot heating.
Since gas heaters require both a supply of gas and a vent to the outdoors, they tend to be permanently installed when used indoors. Single-room heaters are often mounted on outside walls to shorten the length of the vent needed. Gas heaters warm instantly, and when coupled with a fan, can provide rapid heat to warm up a room. Gas prices vary from year to year, but in most cases, gas heating is more economical than electric.
Electric heaters rely on electrical resistance to produce heat. When current begins to flow, a heating element inside the unit begins to heat up, and it may take several minutes to reach optimum temperature. Electric heaters generally use between 500 and 1500 watts of electricity, and on maximum settings, they can push a standard 15 amp circuit close to its limits. Whole-house electric furnaces require their own dedicated lines providing 40 amps or more due to the high power requirements of these appliances.