steven

what area of country do you live?

what size living area will this system serve?

what is your electric rate?

here is the AHRI Directory numbers.

1408915 Active Systems INFINITY 17 PURON AC CARRIER AIR CONDITIONING 24ANA724A30 CNPV*3017A** 58MV(B,C)060-14 23600 11.20 14.50 1 RCU-A-CB 176

you have a nice price although the AC numbers are rather poor for such a premium Carrier AC condenser.

you might want to ask dealer if there is an alternative choice for evap coil mdl that will yield better numbers or perhaps consider the sgl stg Performance 15 condenser which is a great model.

IMO

Tigerdunes, you're right the numbers are pretty poor, relatively speaking. This is a top of the line Carrier furnace and the second from the top AC unit as I understand it. I'm really puzzled as to why the EER is so low? The price, due to dealer and factory discounts and rebates, and the tax credit, is actually less than some other options from the lower grade Performance line from Carrier. I like the fact I'd be gettting top grade equipment, but disappointed particularly in the EER.

steven

what area of country do you live?

what size living area will this system serve?

what is your electric rate?

the numbers on Carrier's Performance 15 are much better. Frankly, I think the two stg Infinitys are overkill for most residential applications especially if not using zoning controls and serving relatively small living areas. Keep in mind while the price may look good on the Infinity condensers, the application and operating costs may be wrong.

IMO

I live in Atlanta GA. The system is for the 1200 s.f. first floor. No zoning, and there are separate systems for each floor. The electric rates are not too high, but a heat pump is out of the question due to my wife's bad experience with one years ago before we were married.

I'm really more concerned about the cooling side, but the 95% furnace gets the 30% Fed Tax credit, so it makes it competitive with lower priced models. He just included a quote of a top of the line system because it was a good deal pricewise. I may still go for one of the Performance systems.

If the furnace qualifies for the tax credit, that's it, so you don't have to worry about getting the ratings with the A/C. 2-stage units tend to get a lower EER in most cases compared to high-efficiency single-stage models. It's still a good system, but the 24APA524A003 or even 24ANA124A003 would likely give you better numbers. Remember that heat rises, so the efficiency isn't as critical as it is for the second floor system. In low stage, the efficiency is higher.

Ryan and Tiger, thanks for the responses. On the return air issue, as mentioned I'm seeing two relatively large return ducts on my current AC. The metal ducts going into the AC unit are around 9 inches or so in diameter I'd say. I'm assuming one goes to the large return in the family room, and one to the return in the upper living room wall.

Assuming the return at the top of the living room wall would be more likely to have the least air flow, would the ducting on that one be able to handle an additional return on the first floor?

I still don't like the idea of adding a return in the basement for a unit that is dedicated to the first floor. The basement is finished and has it's own system (the previous owner put in a system for each level of the house). We use the basement only occassionally and keep the thermostat set to about 62 in the winter, and don't run the AC much in the summer since it stays pretty cool down there anyway.

I wouldn't put a system's return air in space conditioned by another unit, agree with you there. I would however make sure all return ducts are sized properly for the unit you're replacing. 2 9" diameter ducts aren't much at all.

Getting back to this. Aside from taking a salesman's word that the returns are sized properly, is there any way to tell what would be proper sizing as far as the actual return ducts? I know there are general CFM flow recommendations for certain size units, but for example I'm installing the above system (2 ton Infinity 17 AC & 60K BTU modulation furnace) to serve a 1200 s.f. area. Is there something that says I need two, three or more 10" returns? Could I contact the maker, and would they tell me?

Incidentally, I found out I have currently have two 10" returns on my 12 year old system, not 9" as I had previously guessed.

Just purchased a Carrier system (infinity). I am a little concerned with the "Buffalo Boot" filter system though. I spoke with the installers about it and didn't get much of an answer. My concern is that the filter sits loosely in the duct system and is not covered in any way. The furnace is in the basement and is vented outside (also using outside air) with a double intake/output system. By not being covered this filtration system is drawing air from inside the basement into the system. Not only is the basement extremely dusty but there may be Radon in it which is also being drawn into the upper floors through the ducts.
I have thought about placing Duct Tape over the opening to seal the system. (Installers said that covering it would cause a high pitched whistling noise. ) *** I tried it and it did not make a difference ~ But I'm wondering why Carrier would put this type of filtration system in such a high end system. Any suggestions or ideas on this ? Thanks in advance....