Emissivity or (Infrared emittance), is a measure of the ability of a surface to shed some of it’s heat in the form of infrared radiation away from the surface. The results from tests conducted to ASTM C-1371 express the emittance value as a percentage falling between 0% and 100% depending on the product’s performance.

A product with high emittance will shed heat faster than a product with low emittance.

Galvalume sheet has an emissivity of 0.261, a low ability to shed infrared radiation away from itself.

Energy Star® Coatings have emissivity that average 0.90, a high ability to shed infrared radiation away from itself.


This graph illustrates the difference of two product with different emissive properties. When the suns solar energy diminishes at dusk the product with higher emissive properties dissipates stored heat at a faster rate.