![]() | This article has multiple issues. Please help improve it or discuss these issues on the talk page . (Learn how and when to remove these template messages)
|
A fan heater, also called a blow heater, is a heater that works by using a fan to pass air over a heat source (e.g. a heating element). [1] 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, [2] but like any fan, create a degree of noise.
Electric fan heaters can be cheaper than other heaters due to simple construction. [3] 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. [3] 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 110/120 V countries, 15 A is a typical maximum, which results in many models being 1.5 kW. In 220/230 V 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.
Most modern fan heaters have a power setting to determine power output. Some also have a thermostat which switches off heating when the desired ambient temperature is reached. They do not maintain perfect room temperature control, since:
While the fans in fan heaters are electrically powered, various heat sources may be used:
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 of electrical injury 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 fuel-powered fan heaters release all the fumes of combustion into the room, creating a risk of poisoning by carbon monoxide and carbon dioxide. Most installed fuel fan heaters in the first world use a heat exchanger and external ventilation, avoiding that risk by venting the combustion gases to the outdoors.
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 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 failsafe backup device that will blow and disconnect the heating element permanently should the bimetal cutout fail to operate (e.g. due to its contacts welding together) and in so doing prevent extreme overheating which could result in a fire.
Industrial fan heaters use high-output finned heating elements 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 warehouses, shipping containers, clean rooms, shops and other general purpose heating applications. They can also be used as dryers or dehumidifiers 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 fans and various staged controls and over-temperature safety limit controls.
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.
A mercury switch is an electrical switch that opens and closes a circuit when a small amount of the liquid metal mercury connects metal electrodes to close the circuit. There are several different basic designs but they all share the common design strength of non-eroding switch contacts.
Water heating is a heat transfer process that uses an energy source to heat water above its initial temperature. Typical domestic uses of hot water include cooking, cleaning, bathing, and space heating. In industry, hot water and water heated to steam have many uses.
A bimetallic strip is a strip that consists of two strips of different metals which expand at different rates as they are heated. They are used to convert a temperature change into mechanical displacement. The different expansions force the flat strip to bend one way if heated, and in the opposite direction if cooled below its initial temperature. The metal with the higher coefficient of thermal expansion is on the outer side of the curve when the strip is heated and on the inner side when cooled.
A storage heater or heat bank (Australia) is an electrical heater which stores thermal energy during the evening, or at night when electricity is available at lower cost, and releases the heat during the day as required. Alternatively, solar storage heaters are designed to store solar energy as heat, to be released during the night or other periods where it is required, often making it more cost effective than selling surplus electricity to the grid and buying it back at night.
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. Heating elements are used in household appliances, industrial equipment, and scientific instruments enabling them to perform tasks such as cooking, warming, or maintaining specific temperatures higher than the ambient.
Auto-defrost, automatic defrost or self-defrosting is a technique which regularly defrosts the evaporator in a refrigerator or freezer. Appliances using this technique are often called frost free, frostless, or no-frost.
Electric heat tracing, heat tape or surface heating, is a system used to maintain or raise the temperature of pipes and vessels using heat tracing cables. Trace heating takes the form of an electrical heating element run in physical contact along the length of a pipe. The pipe is usually covered with thermal insulation to retain heat losses from the pipe. Heat generated by the element then maintains the temperature of the pipe. Trace heating may be used to protect pipes from freezing, to maintain a constant flow temperature in hot water systems, or to maintain process temperatures for piping that must transport substances that solidify at ambient temperatures. Electric trace heating cables are an alternative to steam trace heating where steam is unavailable or unwanted.
Electric heating is a process in which electrical energy is converted directly to heat energy. Common applications include space heating, cooking, water heating and industrial processes. An electric heater is an electrical device that converts an electric current into heat. The heating element inside every electric heater is an electrical resistor, and works on the principle of Joule heating: an electric current passing through a resistor will convert that electrical energy into heat energy. Most modern electric heating devices use nichrome wire as the active element; the heating element, depicted on the right, uses nichrome wire supported by ceramic insulators.
An electric blanket is a blanket that contains integrated electrical heating wires. Types include underblankets, overblankets, throws, and duvets. An electric underblanket is placed above the mattress and below the bottom bed sheet. This is the most common type in the UK and Commonwealth countries, where it is known by default as an "electric blanket"; in the U.S. and Canada, where it is less common, it is called an electric heated mattress pad. An electric overblanket is placed above the top bed sheet, and is the most common type in the U.S. and Canada, where it is called an "electric blanket".
A space heater is a device used to heat a single, small- to medium-sized area. This type of heater can be contrasted with central heating, which distributes heat to multiple areas.
A thermal cutoff is an electrical safety device that interrupts electric current when heated to a specific temperature. These devices may be for one-time use, or may be reset manually or automatically.
A convection heater is a heater that uses convection currents to heat and circulate air. These currents circulate throughout the body of the appliance and across its heating element. This process, following the principle of thermal conduction, heats the air, reducing its density relative to colder air and causing it to rise.
An oil heater, also known as an oil-filled heater, oil-filled radiator, or column heater, is a common form of convection heater used in domestic heating. Although filled with oil, it is electrically heated and does not involve burning any oil fuel; the oil is used as a heat reservoir (buffer).
An infinite switch, simmerstat, energy regulator or infinite controller is a type of switch that allows variable power output of a heating element of an electric stove. It is called "infinite" because its average output is infinitely variable rather than being limited to a few switched levels. It uses a bi-metallic strip conductive connection across terminals that disconnects with increased temperature. As current passes through the bimetal connection, it will heat and deform, breaking the connection and turning off the power. After a short time, the bimetal will cool and reconnect. Infinite switches vary the average power delivered to a device by switching frequently between on and off states. They may be used for situations that are not sensitive to such changes, such as the resistive heating elements in electric stoves and kilns.
Radiators and convectors are heat exchangers designed to transfer thermal energy from one medium to another for the purpose of space heating.
A ceramic heater as a consumer product is a space heater that generates heat using a heating element of ceramic with a positive temperature coefficient (PTC). Ceramic heaters are usually portable and typically used for heating a room or small office, and are of similar utility to metal-element fan heaters.
Tankless water heaters — also called instantaneous, continuous flow, inline, flash, on-demand, or instant-on water heaters — are water heaters that instantly heat water as it flows through the device, and do not retain any water internally except for what is in the heat exchanger coil unless the unit is equipped with an internal buffer tank. Copper heat exchangers are preferred in these units because of their high thermal conductivity and ease of fabrication. However, copper heat exchangers are more susceptible to scale buildup than stainless steel heat exchangers.
A positive temperature coefficient heating element, or self-regulating heater, is an electrical resistance heater whose resistance increases significantly with temperature. The name self-regulating heater comes from the tendency of such heating elements to maintain a constant temperature.
Overheating is a phenomenon of rising temperatures in an electrical circuit. Overheating causes damage to the circuit components and can cause fire, explosion, and injury. Damage caused by overheating is usually irreversible; the only way to repair it is to replace some components.