Last night was the coldest night of the season and my heat pump doesn't seem to be "keeping up". We have it set on 72 and it was 65 in the house when I got up. Most of the vents seem to be blowing nice warm air where others are blowing air but not as much. The house was built in the late 50 and the heat pump was put in about 7 years ago. The Aux light was also on. Anyone have an idea of why this is happening. Last year we had no heat because it blew cold air all winter. We found the reset button at the end of Feb.