What does a microwave leak detector detect?

A microwave leak detector actually detects microwave electromagnetic energy. There are a number of different types, and it might be best to touch on them before finishing up.

One way to divide microwave leak detectors is by the "quality" of the insturment. There are a number of "cheapie" units that will give an indication of leakage, and then there are the really expensive survey meters that cost hundreds of dollars and should be calibrated at least annually. Both respond to microwave energy, and you can see where this is going.

If you suspect a leak in an oven, it is best to call and ask about a "professional" checkup. It's cheaper to take a machine in than to have someone come by, but for builtin units, you don't have much choice. Make a call and ask a few questions to see what can be done and for how much.