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 heat pump installation & replacement, bring intermittent operation and controls into the scope discussion. Compare single-stage, two-stage and variable-capacity choices by approved system match, room comfort, sound and total scope. Do not assume the largest rebate identifies the most suitable system or that expected energy savings are guaranteed.