New construction two stage verses single

[Dgg]

We are building a new home in the charleston sic area Hot and humid! The home is 4400 sqft with 2850 on first and 1580 on second with 547 worth of 20 foot ceilings.

I had specs 2 stage 16 seer but am struggling with cost. Original plan was 3 units master suite and study 780sqft, rest of lower level 2000 sqft with high ceilings and the upstairs. Manual j by the builder is about 7 ton

Quote came in for a 5 and a 3 which puts master suite on 5 ton with all the high ceilings. To had a zone capability is not much less than adding a 1.5 single stage with two speed VAM.

So at the end question is with SC coastal cooling days will I below the threshold often enough to have 2 stage make sense? Or could I go 3 single stage with two Speed VAM and get near 15 and be in pretty good shape.

House should be pretty tight foaming attic space and under first floor, also used liquid applied membrane and personally caulked all top and bottom plates,jack studs, windows doors etc foamed all cells, and intrusion points.

Thanks for reading this far!

[beenthere]

Are you in an area that reaches 105 outdoor temp? 7 tons sounds big for a spray foamed attic and basement.

[Dgg]

Are you in an area that reaches 105 outdoor temp? 7 tons sounds big for a spray foamed attic and basement.

Yes it can do that easy in the summer. Bases celing will be foamed but is drive under construction so ceiling I'd 8'8" above grade.

[behappy]

I may have misses something here?
Is this an encapsulated home? Attic, walls and floors foamed?

I am In a coastal area and 5 tons is a little big for an encapsulated home.
And yes we use 2 speed HP's for comfort.



Sent from my iPad using my fingers.

[Dgg]

Attic and first floor everything else is batted

I may have misses something here?
Is this an encapsulated home? Attic, walls and floors foamed?

I am In a coastal area and 5 tons is a little big for an encapsulated home.
And yes we use 2 speed HP's for comfort.



Sent from my iPad using my fingers.

[teddy bear]

We are building a new home in the charleston sic area Hot and humid! The home is 4400 sqft with 2850 on first and 1580 on second with 547 worth of 20 foot ceilings.

I had specs 2 stage 16 seer but am struggling with cost. Original plan was 3 units master suite and study 780sqft, rest of lower level 2000 sqft with high ceilings and the upstairs. Manual j by the builder is about 7 ton

Quote came in for a 5 and a 3 which puts master suite on 5 ton with all the high ceilings. To had a zone capability is not much less than adding a 1.5 single stage with two speed VAM.

So at the end question is with SC coastal cooling days will I below the threshold often enough to have 2 stage make sense? Or could I go 3 single stage with two Speed VAM and get near 15 and be in pretty good shape.

House should be pretty tight foaming attic space and under first floor, also used liquid applied membrane and personally caulked all top and bottom plates,jack studs, windows doors etc foamed all cells, and intrusion points.

Thanks for reading this far!

A word of caution, do not live in this space without fresh air ventilation. Most codes are suggesting mechanical fresh air ventilation to purge indoor pollutants and renew oxygen. Also the cooling load is reduced to the point that the a/c will not operate enough to remove the moisture from the occupants and adequate fresh air ventilation. Suggest a small whole house ventilating dehumidifier like an Ultra-Aire XT105H to provide fresh air and humidity control.
Regards TB

[Dgg]

Can you share a little,more detail as it apples to this space?

A word of caution, do not live in this space without fresh air ventilation. Most codes are suggesting mechanical fresh air ventilation to purge indoor pollutants and renew oxygen. Also the cooling load is reduced to the point that the a/c will not operate enough to remove the moisture from the occupants and adequate fresh air ventilation. Suggest a small whole house ventilating dehumidifier like an Ultra-Aire XT105H to provide fresh air and humidity control.
Regards TB