Customer stated that heat strip was working too long and upstairs wasn’t heating enough. Inspected the system, located in the attic. Turned heat on, and heat pump started. Let it ran for a while, with no issue and heat strip off. Turned to emergent heat, and heat strip worked. Let it ran far a while with no issue. Inspected heat pump, checked pressures, amperage in motor and compressor, defrost board and visual. Everything is working properly with no issue. Possible the cause of the heat strip ran longer yesterday was that weather was too cold and below freezing in the moving, and heat pump uses the heat strip , when is too cold outside to help the house to keep warm. Also, there is an air cycle installed to the upstairs system, to bring fresh air into the house . It will turn on every 10 minutes even when the thermostat is satisfied. This is a device that was installed by the builders, it came with the house and nothing to worry about.