bjp

what is your location?

Certainly not inexpensive.

I think the second system is definitely on high side for a 2 1/2 ton non Infinity/Evolution system. You need to have ductwork system checked very closely since you are going up in size.

Depending on location, I prefer electronic demand defrost to eliminate unnecessary and nuisance defrost calls.

IMO

Location = Central VA

On ductwork, he said going to 2.5 ton would work, although he said there may be some add'l noise. He said if we had to go to 3 Ton (e.g. dual speed unit), all the ductwork would have to be replaced $3000+.

What is needed for "demand defrost". Is that an option or a different model?

Can you give me an idea of what the 2.5 Ton system should cost?

The 2.5 Ton is single speed outside. 2 speed only an option on "even" ton sizes (2T, 3T). How important is that? Do other brands offer 2.5T dual speed?

Thoughts on the 4 Ton?

Bjp

Adequate return for both downstairs and upstairs systems? If not now is time to correct.

Considering you will be purchasing two systems, the 2 1/2 ton should be closer to 6K than 7K.

Suggest you google "electronic demand defrost" feature on heat pumps. Unfortunately, Carrier/Bryant do not offer.

Two stage heat pumps are only available on full ton sizes-no 1/2 ton sizes.

What size living space does the 4 ton system serve? Any problems/issues when it was working properly?

IMO

How many square feet or the first and second floors? Do you have a lot of windows, are they double pane, drafty? What are the typical highs for the summer?

You stated a load calculation was done, but 6.5 tons is a lot of cooling. You should get three quotes before you make a decision.

Here is an update. Apologies for the brain dump type post. I am evaluating three vendor quotes, and pursuing trying to get one more. Any advice greatly appreciated!

Constructed: 1999

Upper floor (bedrooms) - ~1600 sq ft
Main floor - ~2000 sq ft
Basement - ~1100 sq ft
(These sizes are from blueprints based on overall dimensions (e.g., interior walls, channels, etc. are included). 9� ceilings / 8� basement).

Other : Dual pane gas filled windows (lower end Anderson windows), 1 skylight in M baths, MBR and MBath have high vaulted ceiling.

Biggest problem area: MBR too warm in summer (20x24 (include 2 large closets), partially over unfinished garage, high vaulted ceilings, 3 supplies, 1 return (low / behind door, needs 16x20 filter, 8" hose duct). Other supply upstairs has 12" hose duct. Other parts of upstairs freeze while MBR too warm. Have been closing supply to rest of upstairs with dampers. Never cooled or heated well. Extensive use of emergency heat IMO.

Current: 4T SEER 10 downstairs, 2T SEER 10 upstairs (with larger air exchanger inside = 2.5T size)

Talked with 3 vendors:
1. Bryant dealer (see OP)
a. Recommending 4T upstairs (16 SEER dual speed compressor - Evolution)
b. Borderline 2.5T / 3T upstairs (says we need $3000 duct mods upstairs to use 3T unit)
c. Recommending increasing return duct upstairs, optional new supply in MBR
d. Bad experience with carrier in the past (1980s)
e. Dealer very responsive on quote. He worked until after 10PM on a Friday night to get me the quote.
f. Recommended by one neighbor.

2. Trane dealer
a. Recommending 4T downstairs (20 SEER dual speed compressor)
b. 2T upstairs (hotly debated, smaller than anyone else and same size as current one that never cooled well)
c. Recommending most extensive duct mods � including up and down stairs
d. Brought high-tech gadgets - put fan in my front door opening and measured air exchange and duct loss. Said we should be exchanging 2x more air than optimal. Duct leakage in supplies about 8cfm, in returns about 20cfm.
e. Recommended by neighbor
f. Longest warranty
g. Proposed to reuse lineset to upper unit (difficult to run new one). But spec calls for 3/8" while old one is 5/16"). Other vendors said new lineset was required. This is big PLUS if using existing lineset is appropriate.

3. Multi-vendor (proposed York unit)
a. Most experienced estimator / owner
b. Recommended 4T downstairs (three options, 13, 15, 18 (2 speed) SEER)
c. Recommended 3T upstairs (same options) with some duct mods (moving return in MBR from low to high with increased capacity, add supply in MBR
d. Recommending to move the pad for the upstairs unit for shorter lineset run (he said otherwise lineset would be over 100ft). Would be giant PITA to move it.
e. Recommended by other neighbor (who bought Rheem from him)
f. De-emphasized impact on electric bill. Said it would make maybe 10% difference over current 10 SEER unit. (I'm hopeful he is trying to lower expectations)

Some questions �

What size upstairs?
Reuse lineset, move pad?
What SEER ratings? (huge price jump from 13 to 16, less from 16 to 18/20)
Which vendor to choose?
How much ductwork to do? (very expensive)

Have any of these guys down a load calcualtion, or are they just they just guessing?

From your description is seems 2 tons is undersized for the upper floor. I think it requires 3 tons based on the area and vaulted ceiling. It also sounds you need to improve the duct work upstairs. I think you need to invest in this area.
On the other hand I think 4 tons is oversized for downstairs. Does the present unit short cycle? If it does then they would indicate 4 tons is too big. I would think 3 tons is sufficient. Talk to the contractor to downsize the downstairs unit and put the savings into the upstair duct work.

You are going to have to change the line set if you are increasing the size of the upstairs unit. If the lines were properly sized they could be flushed, but yoyu have to trust the contractor about doing this properly. Many will cut corners on this.

I like the Bryant dealer because he seems to want to do the job properly. The Evolution system (I have Carrier Infinity) is very nice. Don't over pay for high a higher SEER condenser. A range of 14-15 is fine. You will unlikely see a ROI if you go much higher.

Yes, 2 have done the manual load calculations.

The Bryant dealer just did for upstairs, Trane dealer did for both.

But they used different softwares and got different results. Trane measured room by room and got smaller sq ft. Plus they had the air exchange numbers from their extra testing. Bryant man came up with 2.5T, close to 3T, and Trane came up with 2T. And you are saying 3T as is the other experienced guy.

The only load calc on downstairs was from Trane, who came up with 3.5T, but with a 2 speed compressor, that is still 4T.

The York guy said they should not have combined main floor and basement ducting, and out main floor using should be smaller. Not sure anything can be done with that now. Although basement is unfinished with all ductwork exposed.

I like what the York dealer is doing.

Shorter line sets that are properly sized require less "work" from the system than long lines, even if both sets are sized properly.

And if the ducting and returns are not sized correctly for proper airflow and static pressure, then increasing the system tonnage or blower size alone will not fix this problem. It is very common for splits with rooms over the garage to be uncomfortable. The recommended solution is to increase the air duct sizing as the York dealer has recommended.

Also, if this dealer is very experienced, then he will have the resources and experience to figure out what to do to fix the problems with your system, not just your equipment.