✅ Check filter condition and replace if necessary

✅  Clean cabinet/closet containing heating unit

✅  Clean and inspect burners and ignition system

✅  Inspect plenum and ductwork

✅  Check static pressures

✅  Test for natural gas, propane, and carbon monoxide leaks

✅  Test gas pressure

✅  Test pressure, drains, and emergency functions for heat pumps

✅  Check heating elements

✅  Test emergency operations and safety controls

✅  Inspect flue pipe

✅  Inspect heat exchanger

✅  Test thermostat operation and accuracy