A long time ago, in my previous house, I had an ancient oil-burning furnace (converted to natural gas) ripped out of my basement along with all the assorted radiators and piping, and had a central air system installed. This was 1999 or so, and the house was only 1600 square feet in size. I paid somewhere around $5,000 for all of the demo and ducting work, and enclosed it all myself when they were gone. $5000 in 1999 equates to somewhere around $9500 today, factoring inflation.
We had a very nice man come to the house and give us an estimate for a ductless air system, where he spec’d out five wall units and one outside air handler. The total estimate came out to a hair over $25,000.
Guess I’m going to be humping window-shakers up and down the stairs for a while longer.