The first truly cold week in Chicago is when worn furnace parts give out. A little preparation in September or October heads most of that off.
1. Replace the filter
Start the season with a clean filter, and check it monthly through winter. Standard 1-inch filters often need changing every one to three months; thicker media filters last longer.
2. Test the thermostat
Switch to Heat and raise the setting a few degrees. The furnace should start within a few minutes and the air should turn warm. Replace the batteries while you’re at it.
3. Clear vents and returns
Move furniture and rugs off supply registers and make sure return grilles aren’t blocked. Blocked returns starve the furnace of air.
4. Test carbon monoxide alarms
Press the test button on every CO alarm, replace batteries, and check the expiration date; most alarms need replacing every 5 to 10 years.
5. Check the humidifier
If your furnace has a whole-house humidifier, replace the water panel and open the bypass damper for winter. Chicago’s winter air gets very dry indoors. See indoor air quality.
6. Look at the venting
On high-efficiency furnaces, make sure the outdoor PVC vent and intake pipes aren’t blocked by leaves, nests or, later in winter, snow drifts.
7. Schedule a tune-up
A professional tune-up cleans the flame sensor and burners, tests the igniter, motors and safety switches, and checks combustion and carbon monoxide. See furnace tune-ups in Chicago or call (312) 924-7223 to book one before the rush.