donna

I will make some general comments but will not comment on pricing without knowing specific model/model numbers. But I will say this-your GC and/or HVAC dealer is certainly looking out for himself on upgrade prices.

Carrier/Bryant is certainly a well tested brand.

what size is each zone?

just to verify, this is new construction?

I will assume that with your area/climate, cooling is more important than heating.

Please recheck and verify your electric and natural gas rate. I know the electric rate you provided is incorrect.

without knowing more information, I would say 10 1/2 tons of cooling for 4200 sq ft is grossly oversized for a home with good new construction qualities and tight envelope.

I am not a fan of all flex ductwork-flex for supply runs OK. I would add another return to what I believe is the main floor/downstairs/zone 1. returns should be centrally located preferably in hallways and I don't like the idea of a return located in the living room.

I would not have an air handler or furnace without a var speed blower. I would think an 80% var speed furnace would be fine for your location.

I am not a fan of EACs primarily because they can be problematic and ineffective as most homeowners will not perform the regular cleaning/maintenance that they require.

I would consider zoning zone 2 and 3 off one system with the Evolution 16 two stg system and Bryant's zoning controls.

I will assume this will be your home for many yrs to come. I would insist on seeing a Man J heat/cool load calc in writing broken out for each zone.

IMO

Thanks for your input tigerdunes. Yes this is a new construction. We are getting high end Marvin windows with low e etc., I am having tech sheating installed on roof to counter heat/cold radiation from roof and have opted for solar electric system for electricity.

I am waiting for the specific model/model numbers.

Size of zones:

Zone 1 is 2500 square feet.
Zone 2 is 685 square feet.
zone 3 is 650 square feet.

I will assume that with your area/climate, cooling is more important than heating. CORRECT

I rechecked our electric rate and it appears the base rate is $0.09 We are charged a base rate and then charged tiered rates depending on usage. Gas rate is
$1.25 average.

I don't understand what the return is for? I believe you recommened another return for Zone 1 in the hallway.

Re: Flex ductwork, you recommend - flex for supply runs only. What else is there and what material should it be?

Sorry but could not determine what EAC is. Are you referring to the filter system? Does it make sense to put the filter system on the upstairs area alone? What about the UV system? Is this something that needs changing and maintaining too?

Thank you for taking the time to respond.

Donna

I think someone has their numbers mixed up. You said the house is 4200 sq ft but when I add the zone square footage up I get 3835 sq ft.
From the information you are providing it seems like the units are grossly oversized. Are you getting more than 1 quote? How hot and cold does it get where you are?
I'm usually not opposed to a single return for the first floor since most floorplans are wide open. But 5 tons thru a single return will most likely be noisy. I would also recommend a return in each bedroom.
A decent residential installation will include a supply trunk run down the length of the house. Then flex duct will run to the diffusers. A poor installation will include 3' of ductwork attached to the furnace and then all flex ducts run to the diffusers. Flex duct is not the best for air flow so running a super long run of flex results in poor airflow at the end of the house.

moonsoon

first and foremost, as said in my previous post, you need a load calculation in writing broken out by each zone. I believe 10.5 tons is grossly oversized.

EACs refer to electronic air cleaners which I believe the GAPA is Carrier's model. You need some type of air cleaner for both systems. EACs are not a cure for asthmatics but may help. Don't know about the GAPA model but most require regular cleaning/maintenance and do produce a small amount of ozone. I would not have one personally. I have a 5" pleated media filter that I change once a year. I lean toward the KISS system(keep it simple stupid!). No offense intended.

The "return" air recirculates your inside air. It has to be sized to be in balance with your "supply" air. For example, if you have a 4 ton blower, your ductwork system should be sized accordingly-1600 CFMs both supply air and return air. One large return such as listed in your original post with such a large space will give poor airflow/exchange and most likely will be noisy. That was the reason for my suggestion for another return. And definitely don't place it in a living area-they should be centrally located in your home normally in an inside hallway.

again I know that electric rate is not correct but I will not beat a dead horse. I do think a homeowner should have an apprx idea of their utility rates. what are the tier electric rates?

I don't have a strong opinion on UV lights. Most homes don't have them and I would think they would be better indicated for areas with high relative humidity or to focus on specific problems with your evap coil. You do want Carrier's tin plated coil not the copper models.

as far as ductwork, metal main trunk lines that are insulated with flex for supply and returns would be my choice. check with county building office and see what code is for new construction.

IMO

You are right about the square footage, funnycide.

The upstairs area has two bedrooms/bath, Walk in closet on either side of the house separated by an open sitting room. The part that is missing in the square footage calc. is a tower that rises over the entrance and second floor. The square footage of the tower area is about 230 square feet. I am assuming that the larger system in zone 2 is going to cool the tower area as well.

Downstairs is an open floor plan consisting of dining room, kitchen living room which is about 1400 square feet and other rooms downstairs about 1100 square feet. The HVAC guys has suggested that we put the system under the house (we have a large crawl space) under the living room area. I was told there is no problem with it being there.

Summer temps here can be as high as 105 on rare occasions but average around 90 degrees F. Winters can get as cold as 45 degrees at nights. Daytime around 60 degrees.

How do you propose we address the possibility of poor airflow at end of house?

thanks.

Tigerdunes, thank you very much for your comments. It appears that the general consensus is that the system is oversized. I have a better idea now on what the system should be like and what I want. I will check to see how hard it is to maintain the GAPA system.

I will post again once I have the model and model number which I find odd not to have been included in the proposal in the first place.

I appreciate the help.

Donna

Sounds WAY oversized and lacking return air. You need a load calculation done to determine sizing. 2500 square feet for new construction shouldn't need anywhere near 5 tons, let alone 3.5 tons for 685 square feet (I'd be surprised if it even needs 1.5 tons). Sounds like they just want to "hack" the systems in. Also, as tiger said, I don't mind flex duct for supply runs but do prefer metal trunklines.

3 Systems, each with its own furnace, and 10 1/2 tons of cooling?

You need to find another HVAC contractor ASAP. If he screws the system sizing up this badly, how much worse will everything else be? Do you think he knows what he's doing? Installation is critical. You pay for a bad install, in both $$ and aggravation, for years.

Good luck.