I had my basement finished a few years ago. In order to hold down cost
I let the contractor "tap into" the existing system to supply
heating/cooling to the basement.

I'd now like to rectify the situation so that my heating cooling in the
entire house isn't so "unbalanced".(summer - system struggles to cool
upstairs, winter - system struggles to heat downstairs).

Any ideas as to the best course of action?? Heat pump, replace system
with zoned heating.

TIA