I have noticed this cooling on Benq pjs(DLP), but the Epson ones(LCD), seem like they stop instantly.I'm wondering this myself. I have a 3020 and a 5040 at the moment.
Living Room: Samsung UN65JS8500,Onkyo TX-NR676,Klipsch R-28F,Klipsch RC-62II,Klipsch R-14S,Polk Audio 80 FX/RT(Atmos)
Bedroom: Samsung UN55MU6290,Onkyo TX-RZ610,Onkyo & Fluance speakers
Garage: Epson 5040UB,Elite Screens 125" motorized screen,2xKlipsch RP-160M,4xKlipsch RP-150M,Klipsch RP-450C ,2xKlipsch CDT-3800II-Atmos,Klipsch R115SW,Klipsch R110SW