The ornamental design for a fanhousing, as shown and described.
FIG. 1 is a front perspective view of a fan housing showing my new design.
FIG. 2 is a front elevational view thereof.
FIG. 3 is a rear elevational view thereof.
FIG. 4 is a top plan view thereof.
FIG. 5 is a bottom plan view thereof.
FIG. 6 is a left side elevational view thereof; and,
FIG. 7 is a right side elevational view thereof.
The broken line showing of portions of a fan is included for the purpose of illustrating environmental structure and forms no part of the claimed design.