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 air conditioning repair, bring intermittent operation and controls into the scope discussion. A limited electrical or control repair may be reasonable when the rest of the system is serviceable. Coil leakage, compressor damage or repeated failures warrant a written comparison with matched replacement. Ask what is included in each option and what remains unchanged.