32x60 Shop - Design for standard split system

[gabeancounter]

Would you guys take a look at the attached design and give me some feedback? The shop is broken into 2 area 32x20 and 32x40. I am trying to keep the design simple.
12' walls 2x6 w/ r19. House wrap new construction. Roof trusses 2' on center w R30 and shingle roof.

Thinking 2 ton condenser with 2 1/2 ton air handler gas furnace.

Questions :

Would like to used exposed spiral duct, but unsure about necessity of insulation?

Duct sizes - main supply trunk 16" with 2 12" arms? return 2 - 12" with 18x18 filter boxes at end.

Is the 80% to 96% gas furnaces worth the extra $ for the south?

Thanks in advance for the feedback

 

[bobbyjean]

is the roof an open concept ? the spiral duct is fine to use..think there would be some condensation at start up if unit is not alway's in service....
the twelve inch returns seem to be undersized for 2.5 tons...go larger if possible
as far as efficiency..what is garage used for?

 

[justinjoyal]

is the roof an open concept ? the spiral duct is fine to use..think there would be some condensation at start up if unit is not alway's in service....
the twelve inch returns seem to be undersized for 2.5 tons...go larger if possible
as far as efficiency..what is garage used for?

2 x 12in should be fine.

A single 12in round duct is good for like 600cfm according to charts.

 

[brewchief]

I think you're going to find that you can't clear your door tracks if you run as shown.

Plan your filter boxes around a common size filter, 18x18 isn't found around here except in a 2" version at the supply houses.

Grill/register choice is fairly important to get the air where you need it, we redid our ductwork at our shop last year and my boss about choked when we had more into 6 registers then all the spiral duct and fittings, when he saw how well it worked he ordered everything to do the other side of the shop the same way.

Do you plan on keeping the heat/AC on all the time or just when you plan on using? Do you want to keep both sections the same temp?

What's your location?

 

[gabeancounter]

Bobby,
The roof trusses will be insulated R30 batts and 5/8 rock on the ceiling. Standard 4/12 roof truss. Garage will be used for maintenance of the vehicles, tractor, mower, 4 wheeler, trailers, splitter, saw - all the junk to keep up 9ac.

The smaller back room 32x20 will be used for projects. Welding and light fabrication, wood work, painting, storage of materials.


Brewcheif,
I think you are right about clearance with the garage doors. I guess I should just run insulated flex through the roof trusses to save the space.

I would like to control air flow with the registers if need with some form of dampener.

I plan to keep the hvac on all the time but set around 55-60 in winter and 80-85 in summer. Adjust as need while in the shop.

Less concerned with the temperature in the smaller room and intend to control air into the area with the registers or possibly a dampener inside the duct?

I am located just south of Athens, GA.