Thanks for being so prompt tigerdunes! OK. I spoke to my hvac company and they did indicate that I would not get much of a rebate ($50 for the performance series- what a joke!) unless I get the infinity ($1000 + $1500 tax credit). Unfortuntely, I don't think I can count on the tax credit so this is a big $1500 deal. My upstairs is about 2300 sq ft with an area open to the main floor (large area about 30X20). The existing system worked ok. During very hot days (90+), I had to close the doors in my bathroom (where there is a 12x12 return) because it is above the garage; closing the door kept it cooler. The other bedrooms also get hot because we get full southern exposure but the temperature seemed ok. Again, if I left the bedroom doors open, the air would escape and if I kept the doors closed, it got really cold(BTW I also have a 20x20 return in the hallway upstairs). The same goes for the heat. I would say that I like to keep my a/c between 73-75 (I have an old honeywell mercury-based thermostat - which I know is not very accurate) and during the winter, I like to keep it between 70-73. This seemed comfortable. You are right - my system has a built-in component for an electronic filter system which is not used. I use regular filtrete filters and replace them every 3 months. For the upstairs unit, I do not use a filter. Instead, I have filters in the 12x12 and 20x20 returns. My a/c guy told me that I could get the Infinity system 80% with a 58CVA furnace + infinity control for $9200. Since I am not sure that I can get the tax credit, it would cost $8200. Is this still worth it? My furnace still has about 8 years to go!? He did tell me that a dual fuel heat pump system would cost about $10,300! Is this what you mean by a heat pump condenser or is this just a specific component within the infinity package? I really want to do the right thing but I do not want to waste money. I pay about $2400/yr for electricity and about $2000 for gas. For such a big place, I am not sure if this is too high or if I can really save that much with an infinity system. What do you think?

Call a different guy. Building codes? I did 3 homes (2 rentals)( and a lot of research..months in fact. I ended up with Trane XR13 matched systems in 2 homes. Ten different bids and it's all about the install. HVAC guys can be very helpful, but you have to do some homework and ask the right questions.

I see this happen quite frequently and most times it is incompetence. There are people in the field who may have been there a long time and still can't trouble shoot a compressor circuit. There are those who also prey on the fact most people worry the compressor may go up and it can be costly. Compressors do go up but in my years of doing this work, it is not that frequent. Reading many posts here, I often wonder if indeed many of the compressors/condensing units/whole replacements were necessary. Without being there and seeing for myself, I generally assume the tech. is competent.

The XL20i is a good unit but probably more than needed in a good system. I've never liked the idea of having 2 compressors for future service costs, but it's excellent for dehumidification which is important in your area. Your price shocks me. Either the prices for equipment are low in Florida, or the company isn't making much, or you're installation is very straightforward. The XR15 doesn't impress me with its 79-80 dBA noise ratings. Also, they're pairing it with a non-variable-speed air handler for whatever reason. The Comfort 16 is completely new to me. Looks like Carrier is introducing a 2-stage unit that qualifies for the tax credit in the 4/5 ton sizes now. As far as your old Carrier, I think they've stepped up their game quite a bit in my opinion and I have no issues with their newer units based on the ones I've seen. This 2-stage unit uses a single scroll compressor. Again, I'm very surprised you can get an XL20i for less. Something isn't right there. If you want, you can ask for quotes on Carrier's 25HCB561/FV4BNB006T00 (single-stage heat pump that qualifies for tax credit) and the Trane 4TWX5060A1/4TEE3F65B1 (single-stage, does not qualify).