Heat pump not cooling as expected in San Jose, CA

Issue description:

The heat pump does not cool properly, reasons:

The filters of the indoor unit are most likely clogged. Dust clogs filters and settles on the heat exchanger plates.

Insufficient coolant. It is necessary to lift the bezel and remove the air filters. With a lack of freon, the heat exchanger will not be cold, and its upper part will be covered with frost. It is necessary to eliminate the leakage and add freon.

The temperature sensor on the indoor unit is broken, it must be replaced.

The radiator of the outdoor unit may be dirty. Dust and fluff have accumulated on the heat exchanger, preventing heat release.

The heat pump fan is spinning slowly or is standing still, the blades need to be cleaned and lubricated or the fan motor replaced.

Problem with the heat pump compressor.