Every time I step into my house and switch on the heat pump, I notice that it takes a few minutes for any changes to register.
This was not something that I had to worry about a few years back when my unit was still new.
It came on instantly, and the house would heat up immediately. However, a decade on, it seems as though the unit has to take a few days before doing what it should. Besides that, I noticed that the thermostat setting would also not get to where it was set. It would always be a few numbers less. For instance, when set at 73 degrees, the reading would stick at 69 degrees. This went on for about a week until I decided to inquire from a trusted HVAC professional. As any other responsible homeowner would, I called the serviceman that handles our HVA unit. It turns out that this was nothing to worry about. The cold winter weather tends to take a toll on every unit, especially when it is extreme. Depending on where you come from, the heat pump tends to get to a certain temperature level where it cannot keep up with heat loss, thus losing its efficiency. When this happens, there is a need for supplemental heating such as space heaters to cover for the deficit. It may take a few minutes before the heat pump can re-cycle and catch up with the temperatures set. However, such differences should not be prolonged or too frequent. Heat pumps are designed to be efficient most of the time. If you feel that it is doing the opposite, you must contact an HVAC contractor to fix it. It could be an issue of wrong thermostat calibration or low refrigerant charge, among others.