In Orange County, the furnace may sit unused for months while the AC does the work. By fall, the ducts have carried a full summer of air, and the first cool night sends the heater through the same system.
Santa Ana winds bring dust indoors
Fall is Santa Ana wind season. Dry, gusty winds push fine dust and pollen into homes through doors, windows and gaps, and much of it ends up at the return grilles and in the ducts.
The first heater run
When the furnace starts for the first time each year, many people notice a burning-dust smell. Most of that is dust burning off the heat exchanger, but heavy dust in the ducts gets blown into the rooms as well.
A fall checklist
- Replace the HVAC filter before the first heater run.
- Vacuum return grilles and vent covers.
- Have the ducts cleaned if they haven't been in several years or you see buildup.
- Book a chimney sweep before the first fire of the season.
- Clean the dryer vent before holiday guests arrive.