Furnace Not Heating or Won’t Start in Chicago
If the furnace is not heating, start with the items a homeowner can check without opening or bypassing furnace safety components.
Try these first
Thermostat: HEAT, temperature set above room temperature.
Fan: AUTO.
Thermostat batteries: replace if needed.
Filter: replace if visibly dirty.
Furnace switch / breaker: confirm power only if safely accessible.
Registers: make sure supply and return openings are not blocked.
If it still will not heat
Repeated shutdowns, clicking without ignition, or a furnace that will not respond after the simple checks are reasonable points to request professional help.
Common questions
What should I check if my furnace will not turn on?
Check that the thermostat is set to Heat, replace thermostat batteries if needed, check the filter, and confirm the furnace switch or breaker has not been turned off if it is safe to inspect.
Can a dirty filter stop a furnace from heating normally?
A badly restricted filter can reduce airflow and contribute to overheating or safety shutdowns. Replacing a visibly dirty filter is one of the simplest first checks.
Why does my thermostat say Heat but the furnace is not running?
Possible causes range from thermostat batteries or settings to a power interruption or a furnace fault. Start with the basic thermostat, filter and power checks; if heat does not return, request service.