https://utilityexplained.com/tags/short-cycling/Recent content in Short Cycling on Utility ExplainedHugoen-usThu, 29 Oct 2026 00:00:00 +0000https://utilityexplained.com/blog/why-does-my-furnace-keep-turning-on-and-off/Thu, 29 Oct 2026 00:00:00 +0000https://utilityexplained.com/blog/why-does-my-furnace-keep-turning-on-and-off/<h2 id="quick-answer">Quick Answer</h2> <p><strong>Short cycling — the furnace runs a few minutes, shuts down early, and repeats — is almost always the safety high-limit switch doing its job on an overheating heat exchanger, and the #1 cause is a clogged furnace filter ($11 fix).</strong> The other ranked causes: a thermostat misreading or mounted badly, a dirty flame sensor shutting the burner, an oversized furnace that satisfies the thermostat too fast, and restricted ducts or closed registers choking airflow. Short cycling is worth fixing fast for three reasons: every restart burns the inefficiency of warm-up, the start-stop hammering wears the igniter and blower, and the house never quite reaches temperature — which is why it shows up on bills as a mystery increase covered in <a href="https://utilityexplained.com/blog/why-is-my-heating-bill-so-high/">why is my heating bill so high</a>.</p>