Thanks for the links, Wiscampsin. l like the write up in the 3rd one, and the whole thread following is a good read.
My goal is to get a programmable unit since I want the system to automatically ramp up at say 5:00AM and then 'slow down' at 11:00 PM - bid of set and forget operation. At first I was also wanting auto changeover but choices are limited and cost is high. I do want to retain the Hi-Low fan capability living here in the South.
Looking forward to a good discussion here. Shout out to the OP - l lived in Saint John for many years working at the Shipyard there. Moncton is a cool place and we visited it occasionally.