size does matter

[rikbolen]

what size main trunk do i need to install in the floor trusses before i close up the gable end?......its 1200 sq ft in the garage and 800 upstairs

 

[PAToyota]

Trunk? In trusses?

 

[carguy123]

All the AC guys who have been bidding my house have been telling me to allot 18". That would give me room for a 16" line with 2" of insulation.

I know that in my present house the line is only 14"