My furnace stopped working, what do I check? Here is the honest version: what you can safely check yourself in the next five minutes, what a technician usually finds when it is not that, and exactly what it costs to find out.
By Sweet Life Heating & Cooling, Central Kentucky, KY. Updated September 26, 2026. Rated 4.9 out of 5 across 1026 reviews.
If this means no heat in the house: A home with no heat is treated as urgent and prioritized, often same-day. The emergency button on the booking page gets a callback within 60 seconds.
If one of these fixes it, you owe us nothing and we are glad. If not, the next part is what the visit is for.
Not turning on. A furnace that will not light is most often a clogged burner port or a defective ignition component, and clogged ports come from a burner nobody has cleaned. Unfiltered air is what packs the cabinet, and that is what eventually takes the inducer motor and the circuit board with it.
Igniter. The book pairs the igniter with the sensor and the burner on the same check: when the igniter is out the sensor and the pilot burner are cleaned with it, because the three light the furnace together and the burner door is open once. A new igniter lasts when nothing touches its surface and the air across the burners is clean; the book's handling rule is the whole prevention.
Control board. A board that only lights the burner after the flame sensor is cleaned is a board too weak to read a dirty sensor; the sensor is cleaned with the new board so it starts clean. The handbook names a bad filter situation as one of the things that ends in circuit board failure.
Pressure switch. The book's three reasons a pressure switch will not prove are all blockages, and on a condensing furnace the one that fills the switch tube is a backed-up drain. Clear the drain and the switch sees its draft again. The other two are the vent and the tube: a stopped vent or a plugged inducer port, and the chimney is checked on every call.
These are the causes in the manufacturers' troubleshooting charts and the trade handbooks our technicians train on, in plain words. The visit proves which one it is with a meter before anything is replaced.
Gas pressure set too high overheats and can crack the heat exchanger; set too low it condenses and corrodes it. Either way the next failure is expensive.
The igniter is proved with a meter before it is condemned, and gas pressure is set on every heating call.
$59 on weekdays, $159 evenings and weekends. Published and final, pre-tax, and the price is the price whether we find a loose wire or a bad motor.
Book the $59 visit online Or call (859) 586-6823Real arrival windows, including evenings and weekends. Paying is what confirms the slot; the office calls to confirm the window.