[Nealtw]

HVAC ducts should not exposed to air in the garage, they should be boxed, drywalled, filled and painted so the warm moist air would not contact them.

 

[Nealtw]

It's important to cover HVAC ducts in the garage. they should be boxed, drywalled, filled, and painted to prevent warm, moist air from coming into contact with them. this helps protect the ducts and keeps the air system working properly.

Code is to have the garage sealed from the garage so you don't have gasses from the garage going into the house
If that was done you would not be having garage are in contract with cold ducts in the summer.
You can make them bigger so you could add insulation around the duct work.
Framing Around Duct Work (youtube.com)