Outdoor temperatures below 35 degrees Fahrenheit trigger sharp efficiency losses in your pump
https://precision-insurance-approved.theglensecret.com/restricted-pathways-damage-compressor-efficiency-and-coil-lifespan-during-maintenance-cycles-1
Heat pumps lose efficiency dramatically when outdoor temperatures fall below 35 degrees Fahrenheit, triggering an efficiency penalty that raises your monthly energy bills and accelerates wear on components