Yes, I understand that 140 is the lowest setpoint. My recollection is Harman doesn't want lower temps because of concerns about moisture/condensation. I'm not an engineer but it seems like other designs employing a separate water storage system get around this consideration and may be more efficient. I looked at several arrangements but for me the Harman does the job and has a small footprint. I use heat pumps until temps drop around mid-november and then I switch to the pellet boiler. I don't use the outside air sensor so cycling is minimal and I think my pellet consumption is pretty reasonable.