What is your location? What are the approximate areas of each zone? Is zone 1 the basement?

The American Standard pricing is absurd. Did he at least give you the model numbers?

The Goodman contractor wants to install 9 tons of cooling. On top of that he is recommending to keep your 20 year old furnaces and claims the AC will be rated at 16 SEER. I don't see how he can claim 16 SEER for a mismatched system. It is likely to be closer to 13 SEER. You need to get away from this contractor quickly.

Thanks for responding, Mike. I'm in St Louis. What I called "zone 1" is a main floor master suite & library. Zone 2 is then the rest of the main floor & zone 3 is our three 2nd floor bedrooms.

For the American Standard bid, I imagine he jacked up the cost several thousand (guessing) for combining zones 2 & 3 into a single 5 ton unit with zoning, and moving outside compressors to the opposite side of the house. This was my idea, just to see if it's reasonable to simplify my system. If he would have said that my idea was silly, I'd just move on with 3 systems. I'm just asking... He did not give model #'s. Only the specs I listed.

I have no idea why the Goodman guy wants to increase from 8 to 9 tons of cooling. He did not do load calcs. I think I'm either right-sized or over sized now, as the house is comfortable enough. I'm also doing some additional insulation & sealing with my remodel, so it should only get better. His bid did start with 13 SEER units, for about $1300 less than the above price. The upgrade to 16 SEER was listed as an option. No mention whatsoever about furnace or air handler changes. My furnaces, while 20 years old, are high efficiency & working fine for now. How much improvement in efficiency or comfort would I get with new furnaces? Or is it more about making the entire system work better together?

Also, here's another quote I have, but no option for A/C only (and a mystery why he upped the A/C to 10 tons):
Carrier Infinity systems. $22,287.

Master Bedroom
59TN6A60V1714 60.000 BTU 96% Two stage Heat variable speed blower motor Infinity gas furnace
24ABN724 4 Ton 17 seer Two stage Cooling Infinity a/c
CNPVP4324 evaporator coil
Infinity Total Comfort Touch screen controller
Duro a/c pad
set of vibration absorber pads

1st Floor system
59TN6A100V2122 100.000 BTU 96% Two Stage Heat variable speed blower motor Infinity gas furnace
24ABN736 3 Ton 17 seer Two stage cooling Infinity a/c
CNPVP4324 evaporator coil
Infinity Total comfort Touch screen controller
Duro a/c pad
set of vibration absorber pads

2nd Floor system
59TN6A080V1714 80.000 BTU Two stage variable speed blower motor Infinity gas furnace
24ANB736 3 Ton 17 seer Two stage cooling Infinity a/c
CNPVP3117 evaporator coil
Infinity Total comfort Touch screen controller
Duro a/c pad
set of vibration absorber pads

I'll also give the bid from a Trane installer (who dropped me to 7 tons cooling, without doing a manual J):

Option 1
1- 4TTB3024 - 24,000 btuh (2 ton) condensing unit 13 SEER
2- 4TTB3030 - 30,000 btuh (2.5) ton condensing unit 13 SEER
Total Investment $9250.00
Option 2
1- 4TTB4024 - 24,000 btuh (2 ton) condensing unit 14 SEER
2- 4TTB4030 - 30,000 btuh (2.5 ton) condensing unit 14 SEER
Total Investment $11,400.00
Option 3
1- 4TTR5024 - 24,000 btuh (2 ton) condensing unit 15 SEER
2- 4TTR5030 - 30,000 btuh (2.5 ton) condensing unit 15 SEER
Total Investment $12,050

Air Conditioning and Furnace option

Option 1
1- 4TTB3024 - 24,000 btuh (2 ton) condensing unit 14 SEER
2- 4TTB3030 - 30,000 btuh (2.5) ton condensing unit 14 SEER
1- TUH1-040 - 40,000 btuh 95% AFUE gas furnace with high efficiency fan motor
2- TUH1-080 - 80,000 btuh 95% AFUE gas furnace with high efficiency fan motor
Total Investment $19,950.00

Option 2
1- 4TTB4024 - 24,000 btuh (2 ton) condensing unit 16 SEER
2- 4TTB4030 - 30,000 btuh (2.5 ton) condensing unit 16 SEER
1- TUH1-040 - 40,000 btuh 95% AFUE gas furnace with high efficiency fan motor
2- TUH1-080 - 80,000 btuh 95% AFUE gas furnace with high efficiency fan motor
Total Investment $22,100.00

Option 3
1- 4TTR5024 - 24,000 btuh (2 ton) condensing unit 17 SEER
2- 4TTR5030 - 30,000 btuh (2.5 ton) condensing unit 17 SEER
1- TUH2-060 - 60,000 btuh 97% AFUE gas furnace with variable speed fan motor
2- TUH2-080 - 80,000 btuh 97% AFUE gas furnace with Variable speed fan motor
Total Investment $24,600

I don't know if any of these sizes estimates are correct, but I can guarantee at least one of them is wrong!

You can probably get a few more years out of the furnaces, but changing them now will ensure you will have a matched system. There is some savings by doing the change out now versus later. The matched system will help the AC efficiency. It will not do anything for the furnace efficiency.

If you are adding insulation make sure it is reflected in the load calculation. I am not sure I would combine the two systems into one. Most HVAC contractors do a poor job when it comes to zoning. It becomes a risky proposition.

If he house behaves well with the 3 systems, why would you change it? Zoning warm air brings additional hardware and as Mike said, can be problematic if not done perfectly. You are upgrading insulation and other goodies on the house, so your actual load is reduced. The contractors who did not do a load calc probably looked at your current connected load, asked if you were comfortable in the house and sized off that. With the upgrades to the house, I'd be inclined to think that the 7 ton estimate is best. I would discuss that with whomever you choose. You do want at least the two speed equipment. I would stick with either the AS or Carrier equipment. I would replace the old furnaces now. Not doing so would represent false economy imho. You are really buying the contractor, so you need to go with the one who makes you feel like he will take care of you throughout the process and after.

I appreciate all the input. It really helps to be able to ask someone who isn't also presenting me a $20,000 proposal!

I know that the furnaces can last much longer than air conditioners, and I'm already running high efficiency gas units. I'll never make up the cost difference in NG usage. Is the benefit of a "matched" system more than the equivalent of 1-2 SEER points? Does it make the system more reliable in the long run? Basically, what do I get for the additional $10,000 cost of replacing 3 functional high efficiency furnaces?

If you are determined to keep the existing furnaces, you should just stick with 13 SEER condensers with matching coils.

I wouldn't put Goodman in a dog house. Just so you know how I feel about the brand.

I personally would rather see you get a complete system. You don't have to do all three at the same time.

What is the size of the Iiving area of each zone? Where are the existing furnaces located for each system? Be specific please.

And finally, you mention a partially finished basement. How is this area heated and cooled?

Post back.

IMO

I'n not necessarily determined to keep the existing furnaces, but if I am going to spend $10,000 replacing them, I am determined to know why.

Zone 1- on 1st floor. 1200 sq ft
Zone 2- also first floor. 2400 sq ft.
Zone 3- 2nd floor. 1200 sq ft.

Basement is about 2400 sq ft finished, 1200 sq ft unfinished, but all areas are conditioned. It looks like this is done by Zones 1 & 2, but there are no returns at all in the basement - only discharge vents in the ceiling.

All of the furnaces are in the unfinished basement. On the outside, zone 1 compressor is on one side of the house, zones 2 & 3 are on the other side. I would like to have 2 & 3 moved to the side next to 1, to get them away from our deck & where we spend all of our outside time.

On the furnaces, I believe all existing are 80% efficiency. Correct me if I am mistaken.

You can pair any brand 13 SEER AC condenser with same brand matching coil with your existing conventional furnace. You can not pair high eff AC condensers with your existing furnace.

20 yrs is about the life of 80% furnaces. So I would just say even though they are doing their job, the furnaces are on borrowed time. Might last another 10 yrs,might wink out tomorrow. If keeping, I recommend heat exchangers be thoroughly checked.

Since furnaces are located in basement close to external walls, you could use high eff condensing furnaces for all three zones.venting waste gas and combustion air would be through your external wall.

And one observation is I don't believe a 2 1/2 ton AC is correct size for your main floor system. You indicated existing AC was 3 tons.

Not certain your quoting dealers are aware that system 1 and 2 supply heat/ AC to finished basement area. This deserves further inquiry and questions.

If air in basement is good, I would add several returns. Has this been discussed? Any dealer made mention of this?

Post back.

IMO

LOL at not putting Goodman in a dog house. I just had two Amana systems taken out and came here to read and sort through a lot of differing quotes before I did.. My Amana units were 6 years old and supposedly had 10 year warranties except we didn't get the paperwork and the installer didn't register them. In just over half their expected minimal life span, we paid for multiple repairs and even labor only can easily set you back $500-1000 at a time. I saw what the inside of those units looked like when they were taken out and still on my front walk. We were in for more repairs before long. I wouldn't use Goodman or Amana either. I'm not sure I'd take them if they were free.

The advise you are getting about having a more efficient matched system is good. Not sure if your installation is horizontal or an upflow, but especially with an upflow, you are in for more labor if replace later. I had a 6 yr old system and decided not to go piece meal. When I go to the these parts and those parts, knonwing this sytem would be mismatched and so would the "new" stuff when I had to replace the furnace later, I felt like I was winding up with the chicken nuggets approach to AC, Never as good as the real thing, I decided to clean the slate and start over. With a 20 yr old furnace, I would definitely replace and have a matched system running at peak performance. Just don't get Goodman.

I'm not a pro and don't know all the model numbers, but the dollar amount on the Infinity looks pretty good. We replaced with 2 Infinity systems and are very happy -- but the main reason I opened your thread was to encourage you to sift through the quotes, ask question and even get another quote or two if you need to. Check references and things like Angies list or local review sites. The installer is a big part of your long term satisfaction. . .

My existing Trane XL90 furnaces are high efficiency. Either 90% or 92%. They vent out the side wall via PVC. I know that going to a super efficient 96+% would save fairly little NG.

The basement air quality is good, and our plan will definitely include installing basement air returns. All of the salespeople looked at the basement & are aware of this situation.

From an air quality standpoint, I'm a firm believer in trying to thoroughly mix air. I think all 3 units (including the 2nd floor system) should have a basement return to keep things circulating. At the same time, this part of the country can be prone to radon issues, so I don't want to create basement negative pressure. We'll need to balance basement returns with basement output. What I'd really like to do is to actually create higher pressure in the basement & increase the "stack effect". The second floor is full of returns, and I'm trying to reposition one in our 2 story foyer up to near the ceiling also. I guess I need to keep the basement registers open to increase air pressure.

I would get quotes on XR13 or XB14 AC condensers with correct matching coils. Keep the XL90 furnaces but have heat exchangers checked. That should be lifetime warranty on those heat exchangers. BTW, if memory serves me correctly, those XL90 furnaces are two stage. Correct? You have two stage thermostats for those furnaces?

Clearly, the furnace on upstairs zone is oversized. I would install a complete system. Choices would be XV95 2 stage var speed 60 K size or single stage XT95 60 K size. You could add an XR15 condenser, probably 2 1/2 ton size.

Since you would be keeping the XL90 furnaces, I would stay with Trane brand.

IMO