A fan heater, also called a blow heater, is a

heater Heating, ventilation, and air conditioning (HVAC ) is the use of various technologies to control the temperature, humidity, and purity of the air in an enclosed space. Its goal is to provide thermal comfort and acceptable indoor air quality. ...

that works by using a fan to pass air over a heat source (e.g. a

heating element A heating element is a device used for conversion of electric energy into heat, consisting of a heating resistor and accessories. Heat is generated by the passage of electric current through a resistor through a process known as Joule heating. He ...

). This heats up the air, which then leaves the heater, warming up the surrounding room. They can heat an enclosed space such as a room faster than a heater without a fan, but like any fan, create a degree of

noise Noise is sound, chiefly unwanted, unintentional, or harmful sound considered unpleasant, loud, or disruptive to mental or hearing faculties. From a physics standpoint, there is no distinction between noise and desired sound, as both are vibrat ...

Cost and efficiency

Electric fan heaters can be cheaper than other heaters due to simple construction. The fan carries heat away from the device, which can be made smaller without overheating. The relatively small amount of electricity used to operate the fan is converted to additional heat, so that efficiency remains at 100%. Electric fan heaters can be more expensive to run than fuel powered heaters due to the cost of electricity. This makes them best suited to occasional use rather than as regularly used heat sources. Residential electric fan heaters are limited in capacity by the voltage of the electrical system. In 110/120V countries, 15A is a typical maximum, which results in many models being 1.5 kW. In 220/230V countries, 3 kW is a maximum, however 2 kW is commonly used as it is adequate for most cases. Industrial fan heaters can draw more power than smaller commercial models.

Control

Most modern fan heaters have a power setting to determine power output. Some also have a

thermostat A thermostat is a regulating device component which senses the temperature of a physical system and performs actions so that the system's temperature is maintained near a desired setpoint. Thermostats are used in any device or system tha ...

which switches off heating when the desired ambient temperature is reached. They do not maintain perfect room temperature control, since: * the thermostat is usually attached to the body of the heater, and senses temperature there. * the basic

bimetal Bimetal refers to an object that is composed of two separate metals joined together. Instead of being a mixture of two or more metals, like alloys, bimetallic objects consist of layers of different metals. Trimetal and tetrametal refer to objects c ...

s usually have significant

hysteresis Hysteresis is the dependence of the state of a system on its history. For example, a magnet may have more than one possible magnetic moment in a given magnetic field, depending on how the field changed in the past. Plots of a single component of ...

. * Remote sensors and thermostats with less hysteresis are available but are less common, as they are more expensive and the basic fan heater is satisfactory for most purposes.

Heat sources

While the fans in fan heaters are electrically powered, various heat sources may be used: * Electric heating elements are common, and used in portable plug-in electric heaters. Although they may supply several kilowatts of heat, such heaters are usually small as the electric element itself is small. Since heat is removed by the fan, the body of the heater does not need to be an effective

heat sink A heat sink (also commonly spelled heatsink) is a passive heat exchanger that transfers the heat generated by an electronic or a mechanical device to a fluid medium, often air or a liquid coolant, where it is thermal management (electronics), ...

. * Hot water tubing is used where the heat is provided by a

hydronic Hydronics () is the use of liquid water or gaseous water (steam) or a water solution (usually glycol with water) as a heat-transfer medium in heating and cooling systems. The name differentiates such systems from oil and refrigerant systems. ...

heating system. *

Gas Gas is a state of matter that has neither a fixed volume nor a fixed shape and is a compressible fluid. A ''pure gas'' is made up of individual atoms (e.g. a noble gas like neon) or molecules of either a single type of atom ( elements such as ...

kerosene Kerosene, or paraffin, is a combustibility, combustible hydrocarbon liquid which is derived from petroleum. It is widely used as a fuel in Aviation fuel, aviation as well as households. Its name derives from the Greek (''kērós'') meaning " ...

, and sometimes other

fuel A fuel is any material that can be made to react with other substances so that it releases energy as thermal energy or to be used for work (physics), work. The concept was originally applied solely to those materials capable of releasing chem ...

s such as used

engine oil Motor oil, engine oil, or engine lubricant is any one of various substances used for the lubrication of internal combustion engines. They typically consist of base oils enhanced with various additives, particularly antiwear additives, deter ...

are burnt in high-power fan heaters.

Safety

Electric fan heaters are unsealed appliances with live electric parts inside, so they are not safe to use in wet environments because of the

risk In simple terms, risk is the possibility of something bad happening. Risk involves uncertainty about the effects/implications of an activity with respect to something that humans value (such as health, well-being, wealth, property or the environ ...

electrical injury An electrical injury (electric injury) or electrical shock (electric shock) is damage sustained to the skin or internal organs on direct contact with an electric current. The injury depends on the density of the current, tissue resistance an ...

if moisture provides a conductive path to electrically live parts. Electric fan heaters usually have a thermal fuse close to the heating element(s) to prevent overheating damage in the event of fan failure or air intakes becoming blocked, and a tip-over switch to shut the heater off when the fan outlet is not in the required orientation. Metal-cased heaters may perform better in the case of possible fire-causing faults than plastic-cased ones, since the case will stay intact and is not flammable, but the metal case presents a higher risk of electric shock if a heater malfunctions. Portable

-powered fan heaters release all the fumes of

combustion Combustion, or burning, is a high-temperature exothermic redox chemical reaction between a fuel (the reductant) and an oxidant, usually atmospheric oxygen, that produces oxidized, often gaseous products, in a mixture termed as smoke. Combustion ...

into the room, creating a

of poisoning by

carbon monoxide Carbon monoxide (chemical formula CO) is a poisonous, flammable gas that is colorless, odorless, tasteless, and slightly less dense than air. Carbon monoxide consists of one carbon atom and one oxygen atom connected by a triple bond. It is the si ...

and

carbon dioxide Carbon dioxide is a chemical compound with the chemical formula . It is made up of molecules that each have one carbon atom covalent bond, covalently double bonded to two oxygen atoms. It is found in a gas state at room temperature and at norma ...

. Most installed fuel fan heaters in the

first world The concept of the First World was originally one of the " Three Worlds" formed by the global political landscape of the Cold War, as it grouped together those countries that were aligned with the Western Bloc of the United States. This groupin ...

use a

heat exchanger A heat exchanger is a system used to transfer heat between a source and a working fluid. Heat exchangers are used in both cooling and heating processes. The fluids may be separated by a solid wall to prevent mixing or they may be in direct contac ...

and external ventilation, avoiding that

by venting the

gases to the outdoors.

Internal parts

Residential model

Typical fan heater's internal parts The picture immediately to the right (the top on the mobile site) shows most of the component parts of a typical plug-in electric fan heater. * The

is the coiled wire frame located behind the fan blades. * The

is at the top left. * The heat (wattage) selector

switch In electrical engineering, a switch is an electrical component that can disconnect or connect the conducting path in an electrical circuit, interrupting the electric current or diverting it from one conductor to another. The most common type o ...

is at the top right. * The switch at the bottom is a normally open switch that serves as a "tipover switch" safety device: as long as the heater is standing upright, the switch is engaged and the circuit is closed. * The grip for the

power cord A power cord, line cord, or mains cable is an electrical cable that temporarily connects an electrical appliance, appliance to the mains electricity supply via a wall socket or extension cord. The terms are generally used for cables using a AC p ...

is at the bottom right. Overheat cutouts The next picture shows the two overheat cutouts. The bimetal cutout (left) operates if the device overheats because the intake is blocked or the fan fails, and resets automatically or manually depending on specification, once the heater cools after the operational fault is corrected. The thermal fuse (right) is a

fail-safe In engineering, a fail-safe is a design feature or practice that, in the event of a failure causes, failure of the design feature, inherently responds in a way that will cause minimal or no harm to other equipment, to the environment or to people. ...

backup device that will blow and disconnect the

permanently should the bimetal cutout fail to operate (e.g. due to its contacts

welding Welding is a fabrication (metal), fabrication process that joins materials, usually metals or thermoplastics, primarily by using high temperature to melting, melt the parts together and allow them to cool, causing Fusion welding, fusion. Co ...

together) and in so doing prevent extreme overheating which could result in a fire.

Industrial model

Industrial fan heaters use high-output finned

s in front of a fan to provide a larger airflow and higher kilowatt rating than many smaller residential fan heaters. Industrial fan heaters can be used in

warehouse A warehouse is a building for storing goods. Warehouses are used by manufacturers, importers, exporters, wholesalers, transport businesses, customs, etc. They are usually large plain buildings in industrial parks on the rural–urban fringe, out ...

shipping container A shipping container is a container with strength suitable to withstand shipment, storage, and handling. Shipping containers range from large reusable steel boxes used for intermodal shipments to the ubiquitous corrugated box design, corrugated b ...

clean room A cleanroom or clean room is an engineered space that maintains a very low concentration of airborne particulates. It is well-isolated, well-controlled from contamination, and actively cleansed. Such rooms are commonly needed for scientifi ...

s, shops and other general purpose heating applications. They can also be used as dryers or

dehumidifier A dehumidifier is an air conditioning device which reduces and maintains the level of humidity in the air. This is done usually for health or thermal comfort reasons or to eliminate musty odor and to prevent the growth of mildew by extracting wate ...

s with modified attachments or mountings. Portable industrial fan heaters tend to range from around 1.5 kW up to about 45 kW with either axial or

centrifugal Centrifugal (a key concept in rotating systems) may refer to: *Centrifugal casting (industrial), Centrifugal casting (silversmithing), and Spin casting (centrifugal rubber mold casting), forms of centrifigual casting *Centrifugal clutch *Centrifug ...

fans and various staged controls and over-temperature safety limit controls.

References

{{Home appliances Heating, ventilation, and air conditioning Residential heating appliances Home appliances Ventilation fans Heaters