Editing Heating element (section)

=== Power density ===
Heating element performance is often quantified by characterizing the power density of the element. Power density is defined as the output [[Power (physics)|power]], P, from a heating element divided by the heated [[surface area]], A, of the element.<ref>{{Cite web |last=Toledano |first=Ilan |date=2022-10-04 |title=Understanding Watt Density When Choosing Flanged Elements |url=https://www.wattco.com/2022/10/watt-density-flanged-element/ |access-date=2023-12-27 |website=Wattco |language=en}}</ref> In mathematical terms it is given as:

<math>\Phi=P/A  </math>

Power density is a measure of [[heat flux]] (denoted Φ) and is most often expressed in watts per square [[Millimetre|millimeter]] or [[watt]]s per square [[inch]].

Heating elements with low power density tend to be more expensive but have longer life than heating elements with high power density.<ref>{{Cite web |last=iqsupport91hn7l |date=2014-11-03 |title=Watt Density {{!}} What is it? |url=https://indeeco.com/news/2014/11/03/watt-density-what-is-it/ |access-date=2023-12-27 |website=Indeeco |language=en-US}}</ref>

In the United States, power density is often referred to as 'watt density.' It is also sometimes referred to as 'wire surface load.'