Turn Unit upside down seam of outer screen facing towards you
Loosen wing nut
Remove bottom plate
Have a trash bag ready and remove old filter. Sometimes the outer white screen comes up with the filter. No Problem! It goes right back on
Inset new filter and reverse the steps. NOTE: MAKE SURE THE WING NUT IS VERY TIGHT. Warning never put your face over the exhaust screen when you first turn it on.