(Amd) 104.1 General. The building official is hereby authorized and directed to enforce the provisions of this code.
Can't do it without insulation...
For sure that seems to be the case where building officials will choose to interpret and enforce the code in a way which considers the garage with AC as now conditioned and not exempt from energy code. .
Interesting enough, I found that in some parts of the country, like in parts of Texas, Arizona, Florida, etc. where it gets hot as heck, it's quite common to see some form of cooling - or even heating - in garages. Some homes won't even sell if they don't have them.
In those areas, there seem to be an understanding that the conditioning is permitted because code somehow sees home garages as distinct areas that:
1. Primarily just need to be air tight and insulated against the other normally conditioned occupied spaces. No penetrations allowed between garage and rest of house.
2. Aren't conditioned continually but only on occasions say for when someone is working on a project in their garage. No different from instances in non-AC garages when someone plugs in a portable fan and open their garage door to get air moving to work on something in their garage.
3. People tend to add insulation themselves without the building official needing to tell them once they see their utility bill after running their AC in their garages... since, let's face it, some people will use their garages differently and may stay there longer and not just on occasion.
Personally, I have no idea if I can pull off putting an AC in my garage in my neck of the woods. I'm curious now though and will ask around where I live. It would be cool - no pun intended - if I am able to do so and be able to work on some personal craft projects in my garage when time permits during the hot summers here.