heat pump is a good choice for your location.
I recommend heat pumps to all my clients
who don't have access to natural gas.
two stage two speed vs all are for whole ton units
3-4-5 tons. no half ton sizes.
this usually starts at 15-16 SEER.
itrw few hvac companies will put a 2.5 ton system in.
they don't want to get a call that your house isn't cooling on the 4th
of July when you have 30 people over.
so they oversize.
you pay more equipment cost for more tons, have little dehumidification
and pay entergy every month. over time that utility cost adds up
as entergy is one of the most expensive utility providers in La.
this is why two stage, two speed & vs work well.
this equipment that covers the over sizing by running in low speed
probably 85% of the time, but on the occasions that you have people over,
cooking going on, and the house is busy, the equipment ramps to higher speed.
this way you are comfortable, hvac techs enjoy their holidays and it works out.
costs you more up front..but the savings is for the life of the unit.
the comfort is there because in low speed it runs long enough to dehumidify.
and in low speed it costs less to operate.
it isn't until the house is completed that you know if you need fresh air.
there have been quite a few foam houses that I've tested that didn't
need fresh air.
the performance of the foam install is very dependent upon the installer.
a blower door test will measure air changes per hour.
this determines if fresh air is needed, based on ASHRAE 62.2 ventilation
another benefit of testing your home is that in our state the energy raters
are equipped to not only test house for leakage, but also duct work.
while you are beyond the stage in building that would allow you to
participate in Entergy's program or the state's efficiency program,
you could still get your home's performance tested.
some of us have been in the business since 2000.
these are the raters who can do more than just test.
these raters can give you an overall inspection and point out
areas that need to be addressed.
in hot humid climates erv's are used. energy recovery ventilators.
but they are not the only method of introducing fresh air into a house.
you should talk with your hvac company about
type of unit (heat pump vs electric heat..the most expensive way to heat)
mastic sealing of ducts (not duct tapes)
and fresh air requirements.
best of luck