With the help of many of you, I decided to replace my 9 year old 3 ton system with a:

Carrier Performance HP (25HPA536H..30 or 31 and an

AH FV4CNF005 with 9kw staged heat strips

Carrier Edge thermidistat.

Just before purchase, the State of Florida put their rebate system on hold, so I put the purchase on hold.

BUT, THERE is a NEW WRINKLE!

Here is the situation. My house is 2500 sq. ft, and according to the HVAC salesman, I need 58,000 BTU's to heat it. The house designed by the builder has 2 systems...a 3 ton system cooling the master bedroom and a small 15X15 detached cottage and the rest of the house is cooled by a 5 ton ac/ah

A salesman visited a neighbor of mine, exact same house, (both built within a year of each other) and talked about replacing the 2 systems with one heat pump and one air handler. The HP would be a 15 seer, and it would be zoned so that there would be 3 zones...the main house, the master bedroom, and the cottage.

Is it simply a matter of mathematics...how many BTU's needed and the size of the equipment that you purchase, or is a 2 unit system better or worse than a one unit system.

A one unit system is easier and cheaper to maintain, so why then would the builder design this model, (all 15 of them) with a 2 unit ac/heat system.

Anyway, it seems that the final price for the one unit system, (I am assuming a 6 or more ton- 58,000 BTU's), as well as the 3 zones, and duct work need to support the conversion from 2 systems to one, is only $1500 more than the replacement of my single 3 ton system. I still have a old 5 ton system to deal with.

Does this make any sense to anyone? If I am unclear, please ask me questions.

Thank you

Lenore