Arrived on site and found thermostat set to 66 and room temp at 68. Explained to customer this is to low of a temp to run equipment at. Will cause freeze up issues and can damage compressor. Found good 20 degree temp split in home. Went to outdoor package unit and recorded amp draws, refrigerant pressures, visual electrical check, and motor inspections. System is over 10 years old with no issues noted while on site. Cannot determine any reason for reduced cooling capacity on day previous. Possibly froze system running at such a low setpoint. This is not a callback.