Yes, I've installed LH and RH 3" computer fans. I've labelled the switch "AVIONICS/DEMIST FAN". Even when not running the vent holes provide an outlet for avionics heat. In summer, electronics like to be kept cool so the fans would normally run. In winter the inside of the windshield can mist up, fans intended to run during ground operations and as required in flight. My Cessna 150 doesn't even have a demist vent (although later models did) much less a fan. PITA trying to wipe the inside of the windshield with shoulder harnesses on.