I had the same problem with my 2013 Eagle Premier 351mkts. I had a new thermostat put in and still had the same problem. I finally found out what the problem was. I removed the thermostat and discovered that they had a 1 1/2 hole thru the wall to run the small wires for the thermostat. As the basement is heated , warm air was being drawn up thru the wiring chase like chimney heating up the thermostat from the back causing a false reading. I cut off a piece of swim noodle, ran the wires thru the middle and glued it flush with the wall. I then reattached the thermostat. It solved the problem for me.