[8zeros]

If you are running solar on the same circuits as your utility for your fans, etc., then you need to get a grid tie system, which automatically offsets your bill.
Otherwise you have to run separate circuits and have a way to switch it.
A grid tie system is panels and an inverter. Simple. The inverter is made to add power to the grid to reduce your bill.
Off grid adds batteries and a charge controller. The inverter may not be rated to feed power to the grid.
Combining them together needs specific inverters made to do that and a little more hardware. These will switch to battery power when the utility goes down.
Good information from Stitch up there.