My Heat pump which is a Trane and 20 year old iced up a few weeks ago. The HVAC technician said nothing was wrong , that when the temperature is below freezing I need to turn on the emergency heat.
I did that a received a $430 electric bill this month.
I have not had this problem for 19 years. It froze up again last week so I turned on the emergency heat again.
What could be causing this. Do I need a new thermostat?