I'm about to add on a 600 sq ft home office and am trying to decide which route to take: mini split system for this room OR upgrading the entire central system. I want to do what makes the most financial sense for the long term.
Background: house and central heat pump system is 10 years old - Payne 3.5 ton SEER 10 system - single unit with air handler in attic. House is in south Georgia (HOT in summer) 2100 sq ft. single floor. Only complaint with current system is the bedroom being used for home office stays too warm in the summers due to lots of computer gear generating heat. All this will be moved to the new construction however.
My question is simply does it make sense to spend probably 2.5 times the cost of the mini split system to upgrade and install a new, bigger system even though it should be more efficient?
Informed opinions appreciated!