Took my new 380Th out for the maiden voyage in Lancaster Pa over the Thanksgiving holiday. Just to see if it could be done i only used the heat pump and not the propane furnace all weekend. The temps dropped into the high 20's at night but the heat pump did the trick. At night I did click on the fireplace for the kids in the garage. Anybody that lives in a cooler climate I would say the heat pump is a must have!!!