Surface Area Loading is the electric power per unit surface area. The suitable surface loading is related with the material, size, structure , working temperature, abstraction of heat. While there is a difference on surface loading between industrial furnace and home appliance, so we can not define a general value.
To make our clients much easier to design their industrial furnace, NiWire Industries engineer here attach the below figure shows the relation between furnace temperature and element surface loading. This our research from many years’ experience, including FeCrAl Cr23Al5, Cr25Al5 and NiChrome 80/20 and NiChrome 60/15.