Im looking at installing a mrcool diy 24000 unit after seeing the price of having one professionaly installed. The 2 HVAC guys however dissagree on where to put the head unit. Its a split level house with 2 500sqft levels. One said put it on the main floor and let it blow up the stairs. The other said put it above the stairs so that is blows into the bedrooms and falls down the stairs. Anyone have any advice as i tend to trust the 2nd one as cold air doesnt move up easy.

I have a new Amana 220v 12,000 window heat pump and a 6 year old 4 ton Goodman heat pump which is over-sized for our 2,000 sq ft house. The electric bill is running about $300 per month with the central air alone. I did a test and the window unit seems very capable of keeping the entire house cool with the central air blower running full time when ambient temps were below 90. I realize the window unit may not keep up by itself when temps get over 95. Am I saving any money using the window AC with the central air blower? When winter comes will using the window heat pump with the central blower save money?