Novice with general new construction questions

[jtrammel]

As long as its properly sized (per manual j/d), sealed and insulated it should be ok being 50ft away. There is no way in the world a spray foamed house needs 9 tons. Maybe 4-5 but that's still probably too much. With 9 tons you will definitely need a whole house dehumidifier or 2 to keep humidity levels in check. If you can cut the size of equipment down then the size of the ducting required is smaller so its easier to conceal without cramming it in somewhere or squishing flex into every nook and cranny and restricting flow. Also the return grilles will be smaller and you will have less surface area of duct in the semi-conditioned space (sf attic) so you won't gain/lose as much through the long duct runs. Not to mention it will its less up front, cost less to operate, produce more even temps and remove adequate humidity if its sized correctly

[jtrammel]

Be leery of a builders hvac sub, they tend to put to large of equipment in (because more profit margin) and be on the builders side rather than the homeowner (keeping it cheap) so they put more $$$ in the builders pocket and get to continue doing their sub work. I would want to hire my own subs because what's a few grand more up front to have it done right on a 15-30 year mortgage, a few dollars a month?

[dan sw fl]

Be leery of a builders hvac sub, they tend to put to large of equipment in (because more profit margin) and be on the builders side rather than the homeowner (keeping it cheap) so they put more $$$ in the builders pocket and get to continue doing their sub work. I would want to hire my own subs because what's a few grand more up front to have it done right on a 15-30 year mortgage, a few dollars a month?

With PROPER PLANNING AND an experienced installer, the new construction project would cost a lot less due to use of two 2-ton WITH A LOT LESS DUCT WORK.

Homeowner can come back here in 3 years to tell the builder/hack/ amateur engineer story
_ _ _ _ _ _ _ IF I WOULD HAVE ONLY LISTENED ... ... ... ... coulda, woulda, shoulda, ... ... ... ... ...

[dan sw fl]

Thanks again for the advice Dan. I've asked my builder about the manual J calculations and duct design as you suggested and should hear back after the weekend. I'm pretty sure he told me at the beginning of construction the HVAC contractor did a load calculation for the house but as you suggested, it's worth verifying. The proposal by the contractor, assuming we're using 3 units, was for all of the units to be in the attic space above the 2nd story. 1 unit would supply the 2nd story (3 bedrooms, 2 bathrooms, hall and large game room),1 unit for 1st story below the 2nd story area (kitchen, breakfast area, laundry,2 halls, mud room, bedroom, and dining room), and 1 unit for rest of house (2 story family room, study, hall, master bedroom and bath). Would the unit supplying the family room, study, hall, and master be better off being centrally above these areas in the attic (above study between family room and bedroom) or is it ok for it to be with the other 2 units above the 2nd story game room? In other words, would it be possible for it to cool our master bedroom adequately if the unit is that far away from it (roughly 50 feet away) if proper duct work was used?

ONLY THE ONE WHO DESIGNS THE DUCT REALLY KNOWS
( OR is this case he might think he knows, but this is probably his first house).
I have only done ~ 500.

[loganparker]

It's tough as a consumer to know who to trust. The contractor being used for the HVAC has been in business since 1973, is licensed, and is part of the BBB with no complaints. Not only that but everyone in my area who has a house my size have 3 units as well. Maybe all the HVAC contractors around here are in cahoots. What's a consumer to do? Are the manual j/d reports something a novice such as myself would be able to understand?

[dan sw fl]

1. What's a consumer to do?
2. Are the manual j/d reports something a novice such as myself would be able to understand?

You can trust someone who does Not have their hands in Your Deep Pockets.

1. Stop work until duct layout drawings and equipment specs/ AHRI #s are provided.!

2. Read Manual J8 attachments to post #6.
... Then answer your rhetorical question.

_________ ((( ))) ____________

[beenthere]

Not only that but everyone in my area who has a house my size have 3 units as well. ?

And are all of those houses the same size as yours foamed. And are they all sized the same they want to do yours. If so. Ask them how their indoor humidity is, and if they have to use a dehumidifier to be comfortable.

[energy_rater_La]

spray foam in the walls isn't the way I'd go in my hot humid climate.
rigid foam sheathing would be more cost effective.

the foam sealed unvented attic is worth the investment.

sizing hvac system, designing duct lay out & mastic seal will be less than foam spraying
walls & serve you much better.

in texas the saying is bigger is better...but it doesn't apply to hvac.
too much a/c & you'll have high relative humidity.
and will be uncomfortable in your home.
people in my similar climate have learned this the hard way.
I'd suggest that you not go that route.

another thing to think about is a whole house dehumidification system.

best of luck.