Abstract: An exhaust fan covering system features a cover body with an open end and at least one opening extending through the cover body. An air filter is arranged to be supported on the cover body between the at least one opening and the open end to force airflow to pass through the filter. An air filter for an existing exhaust fan cover features a frame arranged for support on the exhaust fan to carry filter material such that unobstructed portions of the material are positioned between the at least one opening and the open end of the cover. A filter kit for exhaust fan covers of different sizes features a piece of filter material and at least one template dimensioned for placement over the piece of filter material to define a guide for cutting of the piece of air permeable down to fit an exhaust fan cover of known dimensions.