The Carrier is the nicer of the 2 systems quoted mainly due to furnaces. Carrier furnace 2 stage var speed, AmStd furnace 2 stage non var speed. AS equivalent to Carrier would be the XV80 model. However, I would want the Infinity controller/thermostat with the Carrier Infinity furnace. Since you are apparently undersized on cooling and going for a 3 ton from a 2 ton, definitely your ductwork needs inspection as far as sizing both supply and return. If not you will have problems regardless of system selected. I would also want a pleated filter media cabinet if you don't already have one. How many returns do you have for upstairs system and how is return air filtered? I find both quotes absurdly high.

IMO

tigerdunes: Thank you for your quick reply.

There is a separate job to redo the ductwork. I left it out of my post not to confuse things. Currently the attic has flex duct and spiderboxes. A separate quote deals with installing supply and return trunks the length of the attic space and then running from the trunk to the registers with flex duct. The house has 4 bedrooms, one of which is a large master, and a long hallway running the length of the house. There are 2 returns, a 14" in the hall and a 12" in the master that take 1" filters. The additional duct work will include adding returns to the three bedrooms without, and a supply duct over the main stairway which is in a double height foyer. Quote 1 was $5.5k and quote 2 was $4k just for the ducts.

I've not checked the filter system intended for either the Carrier or AmStd systems but will do so now. Thank you.

Thanks for your thought on the AS XV80 furnace. I'll check the price difference. With that furnace do you think the two systems, functionally, are on par?

Thanks for your thoughts on pricing. There was a 3rd quote for Trane equipment which was in line with the Carrier quote, but the contractor was being difficult about providing details on the duct installation they would undertake, so I kicked them out. I'll look for another contractor to provide a quote if these two are really high.

tigerdunes: Is the XV80 model number for Trane or AS? I can only find this model number associated with Trane equipment.

Looking through the AS online brochure, the next step up in the furnace to get the variable speed fan looks to be the Gold 80V (vs the Gold 80 for the model number in my original post) and the similar capacity model looks like the AUD2B080A9V3VB. Is this what you are referring to?

Yes...XV80 is Trane's model number and AS has exact same/identical model.

do your quotes in OP include the new ductwork? For the AS version of XV80, you will require the XL824 thermostat.

going back to ductwork, you want R8 minimum insulation for new system. I am not opposed to flex duct for supply and return runs but definitely you want metal for supply and return trunk lines. I would want 3 returns minimum correctly sized to handle minimum 1400 CFMs. I like individual room returns better.

Just for information, ductwork jockeys are the usually the lowest paid on the HVAC food chain. New ductwork install should be no more than 3 K.

IMO

Thanks again.

Now after looking in detail at the Trane site, I see what you mean about AS having the same features as the XV80. Looks like the AS AUD2B080A9V3VB is the same as the Trane TUD2B080A9V3VB. So similar that I wonder if a 3rd party manufacturer is white labeling them.

Carrier doesn't provide as much detail on their website but as far as I can see the 58CVA seems similar to the two above.

Quotes in my OP are for hvac only. Ductwork pricing is in my second post (Quote 1: $5.5k; Quote 2: $3.9k). Thanks for your thoughts on the returns, I'm going for individual room returns. Thanks again for price thoughts.

With the upgraded AS furnace, do you think the Carrier and AS systems are on par or are there other considerations? (I'm still checking on the pleated filter media cabinet and controller).

Trane XV80 and equivalent AmStd model are truly identical with exception of data nameplate and badging. Just so you know from the model numbers A= AmStd and T=Trane. Yep, it's that simple. The Carrier Infinity and AmStd XV80 are very comparable with exception of BTUs. The AmStd is 80% at 80 KBTUs input while the Carrier is 80% at 70 KBTUs. Both are 2 stage models and require the correct thermostat for best operation.

IMO

I just had an Am Std contractor tell me that there has been problems with the compressor on the 17 SEER AC where they breakdown and need replacement frequently. One unit in particular that they installed needed to have the compressor replaced 3x in 3 yrs. Has anyone else heard of this problem?

not familiar with that...do not like anecdotal stories like the one you just described without hard facts...I consider that the systems you are looking at are very comparable...keep in mind the exact same is available from Trane and Bryant...I frankly don't believe there is an issue without some hard information...

Thanks tigerdunes. I just thought I'd ping the community to see if anyone else had experience with this.

I'm still getting detail to compare systems. Thanks for the media cabinet and controller comments. Neither installer was considering a media cabinet. How frequently do those filters need to be replaced?

One installer was going to leave the existing 1999 controller (the kind my parents had with the little bar on the side that you move up and down to adjust to select the temp ... must be 1970s technology. Unbelievable.)

I think I'm frustrating these guys with all my questions! That's not my intent but it's amazing how much info they fail to tell you.

On a properly sized 4-5 inch pleated filter cabinet like Trane's Perfect Fit Model which i would recommend for either a Trane or AmStd system, filters can last up to 1 yr before changeout. Both OEM and generics are readily available from online filter houses. Changeout is quite easy as long as access is reasonable.

IMO

ok. thanks again for your input.

The Carrier 58CVA070-1-12 is shown on the Carrier website to be a 70,000 BTUH furnace yet the specs indicate the BTU input is 66,000 and BTU output is 54,000.

I have three questions:

1. Is the system marketed based on rounding up the 66k input to 70k?

2. Are all systems marketed based on their input BTU?

3. Is the difference between the 66k input and the 54k output indicative of the efficiency of the system? (54/66=81% so that makes it an 80% furnace)?

You are over thinking everything...Carrier/Bryant and Trane/AmStd have different sizing on their 80% eff furnace models. Keep in mind that with the Carrier Infinity 80 model you listed, you want the Infinity controller (which is pricey) for full functionality. As a homeowner, you want to know both input and output BTUs. Don't be as concerned with the model number as to the BTUs plus the rated size of blower motor. In this case the Carrier blower motor can take up to a 3 ton condenser. I am done here.

IMO

Ok, thanks for all of your help.

I always pay close attention to the AHRI matching system numbers both performance and efficiency. The correct and best matching evap coil does matter!

Ok, I'll check that the final two quotes have matching AHRI numbers. Thanks again for all of your thoughts.

Here are the answers to your questions:

1. Manufacturers round up the BTU ratings to round whole numbers. I am not sure if there are any rules about how much rounding up is allowed.

2. Yes all systems are marketed by the input size. However it is the output that really matters. The output has to be matched to the calculated load.

3. You are correct. The output is the rated input multiplied by the efficiency.

Thanks very much Mike.

So I might be able to guess that a furnace quoted at 80k BTU and 80% is maybe ~76k BTU input so multiplied by ~80% is ~61k BTU output. With similar airflow, the 54k BTU output furnace is going to give me something like ~88% of what the 61k BTU output furnace will give me and I'd think some of that should be reflected in the price.

Anyway, thanks again Mike. I've been thinking about this because the 70k BTU furnace is more expensive than the 80k BTU and both are 2 stage, variable speed, 80%. That seemed backwards to me. At least it gave me an argument for lowering the price of the 70k BTU unit (still waiting for an answer).

You will find that size of the furnace does not have much influence on the price. The features that drive pricing are the number of stages and variable speed air flow. It is hard to argue that a furnace should cost less because it provide fewer BTUs, but you can try.