Why Do Microwaves Make Noise?

Why do microwaves make noise? 

The answer to this question comes down to a handful of things that are crucial to the way that microwaves actually work:

  • The magnetron inside the microwave, which generates the heating waves.
  • The cooling fans that are necessary to keep the microwave cool.
  • The electrical components that power the microwave.

That’s the short and sweet answer to the question! In the rest of this article I’m going to go into greater detail about all three of these noise sources.

By the end of it, you’ll have a complete understanding of why microwaves make the noise they do.

Before we start, it’s important to stop using your microwave immediately if it’s making a particularly unusual racket.

If it sounds like this, in other words, disconnect it from the mains and get ready to buy a replacement!

The Magnetron

The magnetron is a component inside your microwave that generates that all-important energy. It’s typically located towards the rear of the appliance.

The magnetron operates at a frequency that can’t actually be detected by human hearing. If it’s not secured in the chassis correctly though, you will notice it rattling against the walls of the microwave.

So, if you have a rattling noise in your microwave, chances are it’s the magnetron vibrating against the cavity walls. 

There’s not an awful lot you can – or should – try to do about this. Microwave repairs are not something you really want to try yourself.

You might consider getting the microwave repaired by a qualified professional, but it’s quite expensive compared to the cost of simply buying a new appliance.

I wrote an article recently about the benefits of new microwaves vs old ones. One benefit of a modern design is that they typically tend to be a little quieter.

If you decide to buy a new microwave to deal with the problem, Panasonic’s NN-SN966S is well-regarded for balancing power with minimal noise

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The Cooling Fans

When you use your microwave you’ll certainly notice a blowing sound that accompanies every use.

This is the noise of the cooling fans, which are necessary to keep that magnetron cool. If they weren’t there, your magnetron would quickly overheat and fail.

Your microwave may even feature exhaust fans to keep air circulating. If that’s the case, you can expect an even bigger whoosh!

The Electrical Components

Inside your microwave you’ll find a suite of electrical components including the capacitor, diode and transformer.

These three elements are essential for managing the energy that’s bouncing around inside the microwave, although they produce a characteristic hum.

Why Microwaves Aren’t Silent

In a world where manufacturers strive to make everything as whisper-quiet as possible, why has no one managed to make a truly silent microwave?

The answer to this comes down to simple economics.

By design, microwaves are meant to heat food quickly and efficiently. For that reason, they only tend to run for a matter of minutes at a time.

Microwave manufacturers could invest in exciting technology that silences these essential components, but you’d pay a stiff price for it.

It’s a matter of trade-offs. You get a little bit of noise, for a little bit of time, in exchange for a time-saving device that doesn’t cost the earth.

What Noises Should You Worry About?

You’ll know your own make and model better than me, so it’s important to keep an ear out for any surprising noises your own microwave makes.

Anything out of the ordinary though, and it’s time to either pay someone to repair your microwave, or start shopping around for a new one.

If you hear any “ugly” noises like clanking or grinding, check first of all that the turntable can turn freely. Your microwave needs to spin to ensure the food is cooked properly.

This may also be a sign that your microwave has become unsafe to use, so don’t ignore it.

There might even be food in there, so give your microwave a good clean-out before writing it off.

Wrapping Up

Now you know the three main reasons why your microwave makes the noises that it does!

Although it’s hard to find a truly silent microwave, more modern microwaves do tend to be a little quieter. 

If it’s time to find a replacement, head over to Amazon where you’ll find all the usual brands.