An electric space heater

A space heater is a self-contained device for heating an enclosed area.^[1] Space heating is generally employed to warm a small space, and is usually held in contrast with central heating, which warms many connected spaces at once. Space heaters are usually portable or wall-mounted, and should be an electric heater in most cases, because natural gas or propane heating in an enclosed area is very dangerous without proper specialized ventilation systems.

Types of heating [edit]

Space heaters can be divided into those that transfer their heat primarily by convection, or by radiation.

Convective heaters [edit]

In convection heaters, heating elements either warm the air directly or heat oil or another filler, which in turn transfers heat to the air. The air then warms the objects and people in the space. Convective heaters are suitable for providing constant, diffuse heat in well-insulated rooms. Oil heaters warm up slowly but do not reach dangerous surface temperatures; wire-element heaters, which may be fan assisted, reach operating temperature much more quickly but may pose a fire hazard.^[2][3] One particular type of convective heater is the fan heater.

Radiative heaters [edit]

Quartz space heater

Halogen heaters usually comprise tungsten filaments in heat-resistant quartz envelopes, mounted in front of a metal reflector in a plastic case. They operate much like halogen light-bulbs, but radiate their energy primarily in the infrared spectrum. They convert up to 86% of their input power to radiant energy, losing the remainder to conductive and convective heat.^[4] The advantage of halogen heaters is that the radiation they produce is absorbed directly by clothing and skin, without first heating the air in the space. This makes them suitable for warming people in poorly-insulated rooms, or even outdoors.

Power Sources [edit]

Many of these space heaters including those of oil filled radiators are plugged in to an electric power source, most commonly a mains outlet. The power ratings of appliances are measured in kW, which allows an easy estimation of operation cost per hour, as energy is billed in kWh.

Safety issues [edit]

The two primary health risks from heaters are the risk of fire, and the risk of carbon monoxide poisoning. The latter risk accompanies gas and kerosene heaters but not electric ones. The risk of fire from electric heaters may be mitigated by low surface temperatures (as found on oil-filled convective heaters), or by switches that cut power in the event of the device being knocked over (often found in the bases of halogen heaters), or by thermal cut-out switches.

Within the United States, Underwriters Laboratories maintains standards UL 1278^[5] for portable electric space heaters, and UL 1042^[6] for portable and fixed baseboard electric heaters. The General Services Administration used to maintain Specification W-H-193^[7] for electric space heaters, but this was cancelled in 1995 in favor of the UL standards. Additional information on portable heater safety may be found at the Department of Energy Energy Efficiency website.^[8] Also, the "EPA does not currently label space heaters as an ENERGY STAR qualified product...".^[9]

See also [edit]

• Central heating
• District heating
• Electric heating
• Heater (types of heaters)
• Solar combisystem

References [edit]

Wikimedia Commons has media related to: Space heaters