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.

where The resistance per wire length (Ω/m) of a heating element material is defined in ASTM and DIN standards.

Compared to wire, ribbon can be bent with a tighter radius and can produce heat faster and at a lower cost due to its higher surface area to volume ratio.

[8]: 131–132 Heating element terminals serve to isolate the active resistance material from the leads.

Insulation is typically a magnesium oxide powder and the sheath is normally constructed of a copper or steel alloy.

Screen-printed metal–ceramic tracks deposited on ceramic-insulated metal (generally steel) plates have found widespread application as elements in kettles and other domestic appliances since the mid-1990s.

The reflector lamp style is often tinted red to minimize the visible light produced; the tubular form comes in different formats: Removable ceramic core elements use a coiled resistance heating alloy wire threaded through one or more cylindrical ceramic segments to make a required length (related to output), with or without a center rod.

Inserted into a metal sheath or tube sealed at one end, this type of element allows replacement or repair without breaking into the process involved, usually fluid heating under pressure.

Etched foil elements are generally made from the same alloys as resistance wire elements, but are produced with a subtractive photo-etching process that starts with a continuous sheet of metal foil and ends with a complex resistance pattern.

These elements are commonly found in precision heating applications like medical diagnostics and aerospace.

In general, thick-film elements are characterized by their low-profile form factor, improved temperature uniformity, quick thermal response due to low thermal mass, high energy density, and wide range of voltage compatibility.

[13] The thick-film heater patterns are highly customizable based on the sheet resistance of the printed resistor paste.

These heaters can be printed on a variety of substrates including metal, ceramic, glass, and polymer using metal- or alloy-loaded thick-film pastes.

[13] The most common substrates used to print thick-film heaters are aluminum 6061-T6, stainless steel, and muscovite or phlogopite mica sheets.

The applications and operational characteristics of these heaters vary widely based on the chosen substrate materials.

Thick-film heaters can largely be characterized under two subcategories – negative-temperature-coefficient (NTC) and positive-temperature-coefficient (PTC) materials – based on the effect of temperature changes on the element's resistance.

[16] Materials used in heating elements are selected for a variety of mechanical, thermal, and electrical properties.

Trace elements play an important role in resistance alloys, as they have a substantial influence on mechanical properties such as work-ability, form stability, and oxidation life.

Enhancements are intentionally added by the manufacturer and may provide improvements such as increased oxide layer adhesion, greater ability to hold shape, or longer life at higher temperatures.

The tradeoff is that Fe-Cr-Al alloys are more brittle and less ductile than Ni-Cr(Fe) ones, making them more delicate and prone to failure.

[17] On the other hand, the aluminum oxide layer that forms on the surface of Fe-Cr-Al alloys is more thermodynamically stable than the chromium oxide layer that tends to form on Ni-Cr(Fe), making Fe-Cr-Al better at resisting corrosion.

Generally heating elements in a domestic appliance will be rated for between 500 and 5000 hours of use, depending on the type of product and how it is used.

General safety requirements for heating elements used in household appliances are defined by the International Electrotechnical Commission (IEC).

[25] The standard specifies limits for parameters such as insulation strength, creepage distance, and leakage current.