Most garages are not vented so I'm not sure thst you need to worry about it. Did you mean ventilation or heating/cooling?

Just to be clear, the common wall is insulated? How good is the air sealing all around? Is there a moisture barrier?

Are you saying the garage is insulated from the outside? or just between house and garage?

It is pretty uncommon to insulate a garage in our climate. Particularly not with spray foam because the expense is not worth it.

Why would you need ventilation? There is no requirement for ventilation of a garage. Now - it isn't a horrible idea.

It certainly appears to be fully insulated from the outdoors by the description -- insulated walls, roof, ceiling. What is with the roof and ceiling though? That would be an insulation sandwich. I guess with open cell it might not be a vapor barrier sandwich. That would be very bad.

I have a couple of problems with this picture. If a garage is insulated, venting it to the outside is counterproductive unless it is controlled so you vent it when you like and not most of the time. I would think that you would want a garage vented unless you are never going to drive a wet vehicle into it.

We will be installing a fan on a timer to exhaust air out of the garage. With tight garages, you worry about air quality.

I believe the LEED standards say that you have to have an exhaust fan set to run for 15 minutes (or a certain air exchange) to meet requirements.

It's an indoor air quality issue (ask that icky air gets into the house) as well as a "hot and humid as ass" issue in the Carolinas. (I ultimately am thinking of a mini split to help fix this issue.)

jannicone, where do you plan to locate the exhaust fan the where will the makeup air come from? Will the exhaust fan have a thermal fuse to make sure it does not accelerate a fire in case one breaks out?