What you can check from the thermostat and the curb
Check the thermostat is set to heat and the temperature is actually above room temperature. Look at the outdoor unit and clear away leaves, grass clippings or anything piled against the cabinet, since the coil needs open air on all sides to work. Look at the fins for a layer of dirt or flattened spots and see if the fan is spinning when the system is running. Check the breaker box for a tripped breaker, and check that the indoor filter is not clogged, since a dirty filter can choke airflow enough to look like a bigger problem.







