Furnace emits a burning dust smell at the beginning of the heating season.

Safety: A mild burning dust smell for the first few cycles is normal. If the smell is strong, acrid, or accompanied by smoke, shut off the furnace.

• Run furnace: Allow the furnace to run for 15–30 minutes with a window slightly open to clear the smell.
• Clean furnace exterior: Vacuum dust from around the furnace and return air grilles.
• Replace filter: Install a clean filter to capture airborne dust.

If the smell persists or you see smoke, have a technician inspect for electrical or combustion issues.