We have a 3,000 sq feet house we are going to make are permanent home near the beach.  It has a AC unit for the downstairs about 1100 sq feet that is a few years old and works well.  The upstairs is two parts, the front is 1,100 sq feet with an AC unit that works OK, struggles to keep up and is about 10 years old.  The rear addition over the carport is about 800 sq feet, the air handler is in the attic, and the heat pump outside is 100% salt corroded and does not work.  This is in New Smyrna Beach just south of Daytona Fl.

I would like to replace the units upstairs with a single geothermal unit to cool that whole floor, or would I be better to do to units.  And what about the downstairs, would I be better off to go ahead and replace it also at the same time.  I would like to get rid of all the outside compressors if possible.  Can they do one set of pipes outside to handle 2 or 3 inside units?  We have septic so I think the tubes will be a vertical installation.  Solid sand and about 10 feet down to ground water.

What is the cost and options I would have and best approach.  We are in our late 40's and plan to make this our permanent full time home within the next year.  Money is tight but long run might make sense to do it right now.

Thanks

You will need to find a local expert. At least ask about using a less expensive open loop system. With all the sand and that water level, collecting and disposing of water should be easy.

A couple things come to mind when trying to make a decision on your new hvac system. First contact the local building department for restrictions and what they will require. How large is your lot, spacing requirements for bore holes in relation to septic system.Does your present outdoor units have coating protection on coils, if not air source equipment may be worth reconsidering. Do to your close location to beach ,a dehumidifier may be in order to reduce moisture inside home and reduce operating costs of larger a/c units.

A forum member, Curt Kinder (username: engineer) is in your area and he indicates that much of his geo installs are near the beach due to the same corrosion issues. He will very likely pick up the thread within a day or so, but if he doesn't, I'd suggest you hunt him down since he is in your area and probably does a lot of installs similar to yours. His website is below.... http://www.greenersolutionsair.com/

As luck would have it I just returned from a day working on the loop plumbing of a geo system in a big new home in Fernandina Beach.

Two geo units totalling 7 tons share a pair of wells into the Floridan aquifer. You might be a candidate for something similar. Alternatively, depending on ductwork placement feasibility, it may be possible to consolidate down to two or maybe even one system via zoning. We run as many as four zones off a single system, and we routinely drive loads down to 1000 square feet per ton for retrofits and 1200+ SF per ton for new construction.

First step should be an investment grade energy audit, to include a careful load calculation, blower door test, duct leakage tests and energy bill analysis. We do that before advising any substantial energy conservation retrofits.

New Smyrna is a bit outside our normal operating area, but we'd make an exception for an interesting project whose timing falls in the slower seasons (spring / fall)

Slow season= February

November and March hereabouts