Follow the symptom from thermostat to equipment
For Rosemont service, note whether the thermostat display is active, whether the fan runs and whether heating and cooling behave differently. This gives a clear starting point without requiring a homeowner to test live electrical components.
If the system works intermittently, record when it stops and whether the thermostat still calls. A repeatable description is more useful than replacing a thermostat solely because the room feels uncomfortable.
For ac maintenance, bring intermittent operation and controls into the scope discussion. Schedule routine checks before heavy seasonal use when practical. If cooling has already failed, describe it as a repair request so diagnostic time and proposed charges can be addressed rather than expecting a routine tune-up to include every repair.
