If supply and return can be balanced and you can spare the floor space,I don't see any downside. Include new electrical when comparing costs. I would never construct a new home with air handler in attic unless there was room to stand in attic.

Thanks klem1.

If it is moved from attic to garage is there any reason the cost woukd be mlre to do that? my orogonal quote went up $1600 but the estimater/ comoany offered to doscount the cost increase by 50% so it woukd onmy cost me $800 additional

Might want to check your local codes to see if air handlers are allowed in garages.

The 2020 Florida Building Code is based largely on the 2018 IRC with some amendments. Locating air handlers in garages is not expressly prohibited, but any installation would need to meet the manufacturer's and code requirements for access, clearance from combustibles, protection, and need to be elevated in flood-prone areas. Locating an air handler in a garage improves access and minimizes the potential damage due to a condensate leak compared with an attic location, but increases the potential for chemical, gasoline, and paint fumes to be pulled into the system if those materials are used in the garage.