If your furnace keeps shutting off after a few minutes, you're dealing with what technicians call short cycling. It wastes energy, wears out parts, and leaves rooms uncomfortable. Common causes include a clogged air filter, a dirty flame sensor, blocked exhaust vents, or a thermostat placed near a heat source or draft. Sherwood Mechanical breaks down each cause, the simple fixes you can try at home, and the signs that mean your system needs professional attention before it fails completely in the middle of winter.