The Carrier Ductless Heat Pump got put in Friday. It's a SEER 19. 5 so it is very ecomomical to heat or cool, quiet and hangs high on the wall to be out of the way. Tuesday and Wedsday we finish the concrete work in the driveway and around the building area between the retaining wall and the building on two sides. We had thought about using crushed rock in that 3' space between the retaining wall and the side and rear of the building. Even with the 3" of fall from the building to the top of the retaining wall edge for water run off I think too much water would get into the ground below the rock without proper drainage. The concrete will fix that potential problem.