Thermal Response of Super White Elastomeric paint for roof

by Ken Hodor 4/10/09

In the picture of the experiment, 2/3 of the sample roofing was painted with the super paint called Elastomeric and 1/3 was left bare. The material was laid on Green Astroturf and in full sun. Using a non-contacting temperature probe, four temperatures were taken.

1. The air temperature

2. The back side of the painted area.

3. The back side of the non-painted area.

4. The temperature of the AstroTurf.

The temperatures (in Fahrenheit) were taken on various days and close to 12 noon in direct sun in La Jolla, CA.

The air temperature was not taken on the first 2 measurements. So the entries have NA (Not Applicable).

On average the painted Shingle is 32 degrees cooler than the bare asphalt shingle and 50 degrees cooler than the green Astroturf. I cut the two areas apart and found an even greater difference—38 degrees cooler on the painted white. Evidently the dramatic temperature difference caused thermal conduction to decrease the temperature of the non-painted shingle area. So 38 is a more representative result.

This should have a major impact on cooling load for any air conditioning system.