I wrote a big article discussing whether you should insulate your garage.
Insulate floor over garage.
If hvac ducts are routed through the floor assembly the floor joists must be deep enough to install several inches of insulation under the ducts.
How to insulate a garage floor above a concrete slab.
If you have a conditioned room over your garage it would be a good idea to insulate the garage ceiling if it s easily accessible.
Concrete is cold and hard but an insulated concrete slab can make a heated garage significantly warmer and more energy efficient.
Insulate garage floors using rigid foam and plywood prior to applying finish flooring.
A continuous air barrier is installed in the building envelope including rim joists and exposed edges of insulation.
Floor above a garage smaller room over a large garage.
Insulation in floors including above garage and cantilevered floors is installed to maintain permanent contact with underside of subfloor decking.
The options you have for the room in general are fiberglass batts blown in cellulose blown in cellulose injection foam and spray foam.
To insulate the floor of the room above the garage seal the space between the floor of the room and the ceiling of the garage and the top plate and the header joist with insulation.
If you didn t jump over to that article i ll sum up the most important thing you need to know here.
Insulate ducts and plumbing and put them close to the floor.
Insulating the attic above the garage will help keep temperatures in the garage a bit more stable but it won t have any appreciable effect on energy bills.
A floor with ducts also should be insulated with a continuous layer of thick rigid.
Check it out for more details and specific recommendations.
The best way to insulate the finished room over the garage is going to be just like any other room in your house insulate the exterior walls the ceiling or attic and the floor.
This is a smart first step before installing a new floor.
What insulation to use in the garage.
But since it s a floor to the room insulating it won t have as much of an effect as the room s ceiling.
When you should insulate the garage if your home s hvac system does extend into the garage then the attic above it should be insulated as it would for any other room of the house.