You must live in an awful hot climate or an energy inefficient condo,
under most conditions, four ton is a lot of cooling for 2100 sq. ft.
Perhaps equipment is not matched to the ductwork, etc., for a lot of
reasons those units are probably NOT transferring 4-ton of heat to the
outside.

When it comes time to replace those units have an heat-gain heat loss
done on those condos and do whatever it takes to reduce the size of your
cooling and heating equipment ! Where are you located? - Darrell -
udarrell

I agree that a full analysis should be done when time for replacement.
Wondering how much longer my 19 year old Carrier condenser is expected to
last?

Maybe they originally included the basement in the calculations, but then
again it wasn't originally finished. My townhouse is an end unit. Even the
non-end-units have the same size A/C condenser as well. All the units have
two skylights upstairs and there aren't a lot of trees to block sunlight.

Main problem with cooling is that one of the upstairs rooms that faces the
south gets much warmer than the rest of house on sunny days. I actually
wound up installing a portable (kind on wheels) A/C unit in that room to
ensure the temperature in that room stays in the 70s. because there is only
one zone and I keep the downstairs set to 75 during the day. Sometimes on
a sunny spring day (mid 60s or warmer), I have to use the portable A/C in
that one room while the rest of the house does not need any A/C.

J.