Turn off the HVAC system at the thermostat and breaker
Remove vent covers and registers
Vacuum loose dust from vents and accessible duct openings
Use a brush attachment to loosen debris inside accessible ducts
Clean vent covers and registers with soap and water
Replace or clean the air filter
Inspect ducts for mold, pests, or damage
Seal visible leaks with approved HVAC duct sealant
Clean the blower compartment and return air area
Reinstall vent covers and registers
Turn the system back on and test airflow
Schedule professional duct cleaning for heavy buildup or contamination