Heat transfer from the plenum to the room was clearly evident in this IR thermograph. The ceiling grids become “heat sinks” and represent 8.3% the heat load of the surface area of the ceiling if taken collectively.

Conclusion

The performance of A/C system can be severely degraded by heat gain
coming from the roof. An A/C system works by removing heat from the room and dissipating it outdoors. Any heat gain around the supply ducts, return plenum, ceiling and roof-top units contribute to this degradation. In this case study, the heat gain on the A/C system probably reduced the cooling efficiency by as much as 40%.

The owners of this building not only saved re-roofing dollars by extending the service life of this roof, they also will save money in the long run by enhancing the performance of their A/C system.

As an Energy Star-labeled product, Energy Seal refl ective roof coatings reflects up to 90% of the heat from the sun and significantly reduced the heat load on this roof