This is my second column in a series of articles about radiant ceiling heating and cooling systems. My next experience with radiant ceilings was an artistic radiator that I built and installed in my home office basement. It was similar to a panel radiator, except that it was completely made of copper.
Radiant heating and cooling ceiling systems for the hydronics contractor
It seems that early thoughts about radiator color were actually somewhat incorrect: Shiny metallic paint colors suppressed the ability of a heated surface to send out radiant energy waves. When testing non-metallic colors, there was a significant increase in the emissivity of a heated surface. Many of these painted radiators worked just fine, indicating that they were significantly oversized in the first place. It then became a standard recommendation in situations where overheating was occurring to paint the offending radiators a metallic color to help suppress their output.