Q: We use an electronics housing to cool electronic components, and the housing becomes very warm during operation. What effect will powder coating have on the heat transfer rate of the housing? Will the housing become warmer due to powder coating?
A: Yes, the heat transfer rate of the housing will be affected by the powder coating. How much it is affected is dependent on the coating’s composition and thickness.
The biggest compositional influence is the type and concentration of inert pigment. Some of the materials used in powder include titanium dioxide, calcium carbonate, barium sulfate, mica, and wollastonite. The heat transfer characteristics of these vary significantly.
I would start with ASTM E-549 Standard Test for Measuring Heat Transfer Rate. Check this out and then either simulate the test or find a lab willing to perform the test for you.