Oven Thermostat Failure: Signs, Fixes, and When to Replace

When your oven doesn't heat right—either too cold, too hot, or not at all—it's often not the heating element. More likely, it's the oven thermostat, a small but critical component that controls temperature by turning the heating element on and off. Also known as temperature sensor, it's the brain behind consistent baking and roasting. If it fails, your food burns or stays raw, and no amount of tweaking the dial will fix it.

A bad oven thermostat doesn’t always scream for attention. Sometimes it just sneaks in—your cookies take twice as long, or the oven beeps like it’s ready but the inside is still cold. You might think it’s the heating element (and it could be), but if the element glows red when you check, the thermostat is probably lying. The thermostat works with the temperature sensor to read heat and adjust power. When it wears out, it loses accuracy. No fancy tools needed to test it—just a multimeter and 10 minutes. Many people skip this step and replace the whole oven, wasting money they could’ve saved.

Thermostat failure usually shows up after 8–12 years of use, especially in older models. If your oven’s off by more than 25°F, it’s time to check. You’ll see uneven baking, burnt bottoms, or raw centers. Some models give error codes like F1 or E3, but most just act weird. Replacing the thermostat is cheaper than buying a new oven—often under £80 for parts and labor. But if your oven is older than 15 years, or if other parts like the control board are failing too, it might be smarter to upgrade.

What you’ll find below are real fixes from people who’ve been there. We’ve pulled together guides on how to test the thermostat safely, spot the difference between a bad thermostat and a broken heating element, and when to call a pro instead of risking a fire. You’ll also see why skipping maintenance leads to more failures, and how a simple cleaning can delay the next breakdown. No fluff. No theory. Just what works.