Hi All!

I would appreciate any advice on rating different brands of central
A/Cs:
(10-11 SEER, 2 tons)

Carrier
Lennox
York
Coolman

Even though Carrier is rated better, I think Lennox is good enough for
performance, reliability and efficiency

Thank you in advance

Well that ought to spark some debate. There's also Trane, Bryant, and
a bunch of other ones, and people have a lot of energy around which is
the best, sort of like chainsaw brands.

My personal opinion is that it really does matter less which brand you
get than who installs it - the quality of their work. Also I'd go with
the most efficient I could afford because energy prices imo will be
going up a lot in the future.

Consumer Reports does not rate central A/C units online, they do say:

Brand plays some role in the selection. But keep in mind that improper
installation can make even the best system run poorly or need frequent
repair. The most essential criterion, however, is efficiency, assuming
the unit has the proper cooling capacity. According to the contractors
we surveyed, units with a SEER of 11 to 14 tend to hold up best. The
contractors believe that high-efficiency systems--a SEER of more than
14--tend to be more complex, with more that can go wrong.
Low-efficiency, low-cost builder's models, perhaps due to design
shortcuts, also require more repairs, the contractors say.

Here are other factors that may affect reliability, according to the
contractors:

=B7 Matching new equipment with old. If you replace only the condenser,
you have a "field-matched" system that can be less efficient than
advertised and that may require more repairs because of undetected
incompatibilities between the two.

=B7 The type of compressor. A reciprocating compressor is more
trouble-prone than a scroll-type one, they say. While pricier,
scroll-type compressors do tend to be higher in efficiency and quieter
than reciprocating compressors. Most manufacturers offer both types of
compressor.

=B7 Damper-zoned cooling. A large or multistory house is often divided
into several heating and cooling zones to improve temperature control.
However, this type of system is complex and has many more moving parts
and controls and so may require more repairs.