Garage isnt insulated so I might ask. To increase insulation around the house was about $1300, not sure if have budget for that.
Take the option to increase the insulation!!!!! especially in the walls,
in a house like that its not too hard to get at roof insulation, ( its a bit of PITA, but it can be done by the owner, but once the gib goes on, the wall insulation become uneconomic to touch...
Even if you have to drop/delay something else, in the grand scheme of it, $1300 on house insulation will pay it self back multiple times over the years... (
It looks like he's already quoted for R2.6 in the walls. If I understand things correctly (and I'm 100% no expert!!), you can only go up to R2.8 before you need thicker walls and a much larger cost increase (I'd be curious to know how much though). I can't imagine 0.2 being worth it when compared to how else the money could be spent, but it sounds like the ceiling should be pretty cheap to upgrade compared to the walls.