I got a lot of good information from your posts and have some ideas of what to look for in the units and what to compare between them. Howvever, I am a single mom and I don't want to be taken advantage of by a salesman.

Can you give me some advice on appropriate questions to ask the dealer / sales person?

I have a two story house at just under 3,200 sf. I have two units which are 16 years old and both have leaks in the coils of the air handlers. My electric bill is budgeted at $350.00 / month.

The first floor is about 1400 s.f. and uses a 2.5 ton Trane XL 1000 HP.

The second floor is about 1800 s.f. and uses a 3 ton Trane XL 1000 HP.

I am planning to install 15 seer units. Price will play a big part in my decision as this is going to be a very expensive repair / purchase. I live in central Florida and a/c is used the most with the heat being used less than 14 days or so per year.

I read on one of the posts that Trane's higher price may be due to their advertising. Do you agree?

Non coastal location?

I prefer a small dealer where owner is actively involved in business, sales and service/repair.

Not a fan of Lennox heat pumps.

Here is my checklist. Correct sizing is important for comfort and operating cost.

there are three equally important components-quality HVAC, the install by dealer, and probably the most overlooked and disregarded is the ductwork system.

these are my minimum specs for a new HP system. both outside and
inside units should be replaced to have a properly matched system.

15 SEER, 12.5+ EER, 9 HSPF
best matching VS air handler
full BTUs in both cooling and heating for your rated size
R-410a refrigerant(same as Puron)
scroll compressor preferred
electronic demand defrost preferred
thermostat with "dehumidify on demand" feature
staged backup heat strips
new and correctly sized refrigerant lineset
10 yr warranty compressor and parts
AHRI matching number for the system quoted

you want a thorough inspection of your ductwork system. size, overall condition, supply and return lines, insulation qualities, leak test, etc.

any hot/cold spot issues in your home should be addressed.

I would look at Trane/AmStd,Rheem/Rudd,Carrier/Bryant.

Depending on location and winter climate, I would not purchase a new HP
system that did not have electronic demand defrost feature. Electronic demand defrost eliminates unnecessary, nuisance, and expensive defrost
calls. Not important though for your location.

Trane and it's dealers do think highly of the brand, sometimes a little too much. Look at their sister brand, American Standard that is very similar and usually priced better.
IMO

Just IMO that I have heard all our married life.

Creek

All the brands use components made by third party manufacturers. The components will vary in specification and performance level. The overall design of the equipment will determine how well these components will perform over a long period of time.

The statement that equipment from all brands is the same is misleading.