Side effects of wire mesh inside vent covers
Typical screening can reduce airflow about 50 to 70%. This could destroy the efficiency of your AC and heating units and possibly burn out the fan. Placing any type of screen on intake or exhaust of your furnace could cause it to shut down as it thinks there is a blockage in the venting. Your furnace /AC unit already has a filter on the intake side of the fan so you wouldn't need screening on the individual vents in the rooms.