My house is 20x30 and 1.5 stories (6' concrete basement). The basement height is just functional at 6' and I'd like to minimize obstructions (e.g. sprawling supply ducts). I'm planning to switch from window AC to central cooling but, to limit horizontal ducting and plenum height issues with the adding the condenser to the furnace, I'm considering positioning a cooling-only system near the duct stack that deals with house's 2nd fl. and kitchen. (supply & return) and leave only 1st fl return to the furnace (for safety) and have the supply plenum pump heat into the basement to then heat the house through convection. We were able to maintain 70 degrees with 6 "radiator look alike"/electrical type so we could maintain some of them in corners of the house that might not get the full warmth. I see it as essentially creating 2 zones (roughly upper and lower with some overlap) and letting the allowing the secondary zone to passively climatize. The synthesis of priorities is to maintain comfortable climate while also maintaining functional use of the basement. Thoughts/alternatives? Thanks in advance.