I want to mount a Honeywell TrueSteam whole house humidifier on my gas heater in our garage, but the ductwork is wrapped with insulation. Do I have to remove the insulation or can I simply cut a whole through it and mount the TS on top of the insulation?
I would remove the insulation and securely mount it to the duct. It is a bit difficult to remove the bottom to service the unit so the tighter to the duct it is the better IMO. Make sure you don't block any ventilation vents on that unit if it has them.