Standard AHU re-insulation: This will typically include reinsulation in the blower and coil housing, and again will use a closed-cell insulation. This is a great service to add when completing a full AHU clean-out.

Benefits:
Will increase the insulation value and reduce heat/cooling loss.
Will not contaminate your nice clean system and indoor air, with fiberglass particulates that blow off with air flow in typical insulations.