My microwave oven stopped working recently. I bought a new one. Now, I’m having to adjust heating times. Hot water is heating up almost twice as fast, for example. Both the old and new units are 1000-watt output ovens. Why is the new unit so much stronger? Because the old microwave, it turns out, has surely weakened over time. Microwave ovens put out measurably less microwave power as they age!
- Why Do Microwave Ovens Lose Power Over Time?
- Magnetrons Go Bad
- How Long Do Microwaves Last?
- How Long Do Magnetrons Last?
- Should You Buy A Microwave Oven Higher than 1000 Watts?
- Is It Safe To Use An Old Microwave Oven?
Why Do Microwave Ovens Lose Power Over Time?
While there are undoubtedly many factors that could affect the power output of a microwave, the biggest factor in an aging unit is the magnetron.
The magnetron is the heart of the microwave oven. They were invented first, paving the way for the development of the first commercial microwave ovens. Before they became a part of microwave ovens, they were used in early radar systems and later as part of linear accelerators. A magnetron is beyond my understanding. They are extremely complicated. I won’t try to explain it but here is the Wikipedia explanation:
The cavity magnetron is a high-power vacuum tube used in early radar systems and subsequently in microwave ovens and in linear particle accelerators. A cavity magnetron generates microwaves using the interaction of a stream of electrons with a magnetic field, while moving past a series of cavity resonators, which are small, open cavities in a metal block. Electrons pass by the cavities and cause microwaves to oscillate within, similar to the functioning of a whistle producing a tone when excited by an air stream blown past its opening…1Wikipedia contributors. (2024, April 13). Cavity magnetron. In Wikipedia, The Free Encyclopedia. Retrieved 22:58, April 23, 2024, from https://en.wikipedia.org/w/index.php?title=Cavity_magnetron&oldid=1218796845
Magnetrons Go Bad
Let’s just say a magnetron generates short radio waves called microwaves. You can read more about how these radio waves heat food here at CulinaryLore.
Clearly, I am not a magnetron expert. But, according to my research, magnetrons do go bad. They weaken over time and can fail due to a number of reasons. The filament within the cathode ray tube is one of the main causes of magnetron weakening or malfunctioning.
Besides the filament, other things cause the magnetron to weaken over time. All of them have to do with how much the microwave is used but the type of parts used in an individual unit may cause unexpected problems. A cheap bargain-basement microwave oven should be expected to degrade faster than a higher-quality one.
How Long Do Microwaves Last?
For the first five years of your microwave oven’s life, depending on usage, you will probably not experience any noticeable reduction in power output. After five years, studies have measured a 5% power loss. This power loss can increase to 30% in ten years.
Although the life of microwave ovens will vary, the typical useful life is 13 to 15 years. By the time a microwave is this old its power output may well have decreased by half!
If you have an old microwave, it probably is much weaker than when you bought it. You have probably been unconsciously adjusting heating times without even noticing the gradual degradation of the power output.
As for when a microwave is past its useful life, again, it will vary depending on how much you use it. It is possible for a microwave to last twice as long for you as it would for another person.
How Long Do Magnetrons Last?
The average lifetime of a magnetron is 2000 hours but there are certainly lower-quality magnetrons in use. At 2000 hours, if you use it 15 minutes a day, it would last 20 years. When everyone in the family uses the microwave, it’s pretty easy to exceed 15 minutes a day.
The longer your microwave takes to heat food, the more the magnetron gets used. So, lower-quality magnetrons shorten their own life by being inefficient. As well, a microwave rated to a weaker output will take longer, thus resulting in a shorter life. Springing for a 1000-watt microwave may be worth it if it means it lasts much longer than a 600-watt oven.
Should You Buy A Microwave Oven Higher than 1000 Watts?
Don’t take the above logic too far. Whereas it may stand to reason that a 1700-watt microwave would heat food faster than a 1000-watt oven, thus lasting longer, most recipes and frozen food instructions are based on a 1000-watt microwave oven. Also, other factors determine the life of a magnetron rather than just how much it is used and for how long. Rough handling, for example, could damage certain components.
The constant adjustment and aggravation of having a microwave that far exceeds what most people have in their homes may not be worth it. You’ll have to adjust cooking times and you may still end up overheating or ruining food. For best results, go with a 1000-watt microwave.
Is It Safe To Use An Old Microwave Oven?
If your old microwave does something other than heat your food, however slowly, it may not be safe. If it emits smoke, sparks, or gives off a burning smell, then do not use it and replace it immediately.
If the door does not close properly then the microwave may not be safe to use. However, most modern microwaves will not function if the door doesn’t latch. Otherwise, an old microwave may not work as well as it once did, but is still perfectly safe.
