The bare minimum basic repairs to get the system running today. Came out for a no heat upon arrival the outdoor unit was completely frozen about 4 to 5 inches thick. Customer stated that she turned off the unit yesterday and only ran an emergency heat. Gave estimate to thaw out outdoor unit. Got all the ice off the unit ran system for almost an hour. System is running at over 20° temperature split and heat mode only with no auxiliary heat once the system got back up thermostat Rose 2° in that run time. Found that the filter was extremely dirty due to pressures and temperature split being good lack of airflow is what caused the outdoor unit to freeze up. System is now heating properly on departure and changed customer supply filter.