I had recently written a scathing review after owning the unit for ten months as the unit was struggling to hold temperature. If this should happen to you, don't send the unit back if in warranty too soon. Pull the unit out and check the four screens in the rear of the unit to see if they are obstructed with dust. Clean the screens using a vacuum OR remove them, wash them and replace them. Your unit should return to normal operating conditions and hold temperature by the next morning. (In my case, that's exactly what happened).