New unit would not come back on after temperture reached 32 degrees, another service call, they said Lennox co did not put a big enough thermostat in their units to hold up to o, dregree weather several days at a time. They had to put a bigger one in to hold up to cold temperature. I had my new unit for 8 months now, had a least 5 service calls on it, another one is on the way, unit is making humming noise., even when it is shut off. The fan was also defected that Lennox co. Has problems with and plastic shroud that also was replaced, they also came back on another service call ,the unit was making knocking ,and ticking noise..