26 Microwave Facts, at Least 5 Will Surprise You!

While talking to various people about microwaves, I’ve noticed that while many people use microwaves, very little is actually known about them. This post aims to know the lack of knowledge with 26 facts about microwaves. 

These facts are going to cover the history of microwaves, common misconceptions, and just about anything else you can think of.

1. Invented by Percy Spencer

Spencer invented the microwave by accident while building magnetrons (more on these later). At the time, magnetrons were a major component in building radars during World War II. While working on magnetrons, he noticed that the candy bar stored in his pocket melted. 

After further investigations and experimenting with other foods (also more on this later) he realized that he could cook foods with these microwaves. 

Spencer lived until 1970, just before seeing how important microwaves would become in our everyday lives. It appears that no one (on the internet) knows his cause of death, which lets people believe that his cause of death is due to him being around microwaves.

2. Originally Not Intended for Domestic use

In the beginning, microwaves were mostly used in restaurants and commercial establishments. There were a few reasons why they began in restaurants, first, microwaves were perfect for cooking foods the night before and reheating the next day. Businesses could server food faster, and increase profit by making food the night before, refrigerating, and reheating later. 

Second, early microwaves were very expensive. In addition to being expensive, microwaves were much bigger than they are now. As you will see in the next few points, microwaves were not practical for domestic use…yet.

3. First Microwave Was the Size of a Small Horse

The first microwave was 6 feet tall. In addition, the microwave weighed more then 750 pounds. Compare this to today’s refrigerators which are around 6 feet tall and weigh 250 pounds. The original microwave weighed 3 times as much as todays refrigerators.

As you can see, the original microwaves weren’t very practical for a domestic home. Eventually, as the microwave aged, the size began to shrink. 

4. And cost as Much as a Used Small Car

In addition to the microwaves being huge, the price was also steep. In the beginning, microwaves cost around $5,000 EACH! Adjusted for inflation, a microwave in 1950 would cost over $52,000! The size and the cost were the main reasons why microwaves were slow to adopt in the beginning.

Thankfully, you can purchase a microwave for a little as $50. While this microwave will not have the highest wattage or the biggest size, it will still outperform a microwave built in 1950. Check out this buying guide to find the right microwave for you

Originally, I found a car, that you can buy with $5000, but not that I’ve adjusted for inflation, you could purchase a new luxury vehicle for $52,000.

5. In 90% of US homes

One of the most interesting facts I’ve stumbled across is that microwaves are currently in over 90% of US homes. If you factor in dorm rooms and offices, I would assume there are enough microwaves for almost every adult in the US. 

For example, there are 7 microwaves, and 1 toaster oven at my work, I have two microwaves here at home (1 for family, the other for testing). As I mentioned here, a lot of what we know about microwaves is false, half true, or information passed down from our parents. 

Besides appliances and TVs, is there anything else that is in 90% of US homes?

6. Microwaves have a Lot in Common with Your WIFI

Believe it or not, but microwaves and WIFI routers operate at the same frequency. WIFI routers send and receive data that is sent to a modem. Modems then send the data to the internet. This process continues whenever you have an open internet connection.

Many older routers send and receive data on a 2.5 gigahertz microwave frequency. Microwaves, on the other hand, cook food using a 2.45 gigahertz frequency. This could be the reason why some people experience interference when using a microwave that is to close to a router. 

7. Microwaves Cook Food with Friction

Most people aren’t aware of this, but microwaves use friction to cook food. Using a safe form of radiation, microwaves cook food by getting the foods’ molecules to bump into each other. This is how microwaves convert energy into heat.

In addition, microwaves are shot into the microwave box and bounce around until it comes in contact with food. 

The only drawback is foods cook so fast, they can become dehydrated. I discuss dehydration later in this blog post. 

8. Microwaves Heat Water, Not Oil

Microwaves heat water very well. Because of this, water is used to steam food, clean the microwave, and cook pasta. The reason water works so well is these are the molecules that vibrate when they come in contact with microwaves. Once the water molecules come in contact with the microwaves, they create heat. 

Oil, on the other hand, does not create heat very well. As we know, oil and water don’t mix. Oil and water are polar opposites, oil has no water components, and doesn’t work with microwaves. While oil cooked in a microwave may get warm, it will not heat to the temperature of plain water.

9. Microwaves Don’t Steal Nutrients from Food

Another common misconception is that microwaves steal nutrients from food. I’m sure you’ve seen or heard stories in which they claim that you should not use a microwave because they zap all of the nutrients. 

Recent studies indicate that while any type of cooking is harmful to the nutrients, the shorter you cook the food the better. These studies indicate that microwaves save the highest amount nutrients of all the different ways to cook food.  

10. Outside in, Not Inside Out

Another common misconception I’ve seen on may websites is that microwaves cook food inside out. Somehow the microwaves penetrate to the middle of the food, cook that portion, then work it’s way out. 

According to the Food and Drug Administration (FDA) 

Although heat is produced directly in the food, microwave ovens do not cook food from the “inside-out” When think foods are cooked, the outer layers are heated and cooked primarily by microwaves while the inside is cooked mainly by the conduction of heat from the hot outer layers,

Microwave Oven Radiation, FDA

The FDA has spent years studying, approving, and rejecting microwaves if they say it’s outside in, I believe them

11. Empty Cooking Will Kill Your Microwave

One thing you should absolutely not do to a microwave is to run it while empty. Doing this can result in damaging your microwave including smoke, and starting a fire. 

As I’ve mentioned, microwaves are little waves of energy that are sent to a reflective metal box. If you run your microwave with nothing to absorb the newly created energy, it returns to where it is created, the magneton. The magneton cannot handle all of the energy, and smoke/ fire is created. 

12. But Your Microwave Won’t Kill You

Yet another huge myth is that people, especially men, should not stand in front of the microwave. Many believe that standing in front of microwaves can cause cancer and reproductive issues. The cancer scare “scare” is based on the microwaves and radiation that is created when a microwave is on. 

While I still see and hear this myth a lot (thinking of an episode of “Everybody Loves Raymond”) there is no health concern by standing in front of a microwave for two reasons. First, the microwaves are blocked by the door. The glass on the door is sealed shut and doesn’t let anything in or out. 

Second, a person would have to stand in front of a microwave for an extended period of time to elevate their risk of cancer. In addition, there would need to be a hole or break in the seal for the microwaves/ radiation to escape. 

13. If it’s Good Enough for NASA…

It has been reported that NASA Astronauts use microwaves at the space station. And as I mentioned in the title, if it is good enough for the astronauts, it is good enough for me.

14. Microwaves are All Around Us…

Another fact that most people miss is that there are microwaves all around us. In addition, to microwave ovens and WIFI routers, here are a few more examples of items that us microwaves:

  • Cell phones
  • Remotes
  • Radios
  • Cell phone towers
  • Cable Tv
  • Satellite TV
  • Air planes

As you can see from the above list, just about anything that sends or receives information wirelessly uses a form of microwaves. Microwave ovens are only singled out because they point the microwaves directly at your food. 

15. Chocolate and Popcorn

AS we now know, the first microwaved food was chocolate when the candy bar in Dr. Spencer’s pocket melted. Did you know the second cooked food by Dr. Spencr was popcorn? While testing his theory, Dr. Spencer used a number of different foods including an egg and popcorn. 

As you might have guessed, the egg did not work, but the popcorn popped. He is solely responsible for our love affair with popcorn while watching movies. 

16. You Can/ Can’t Use Metals in a Microwave

This is another hotly debated topic amongst friends and family. The truth is you can use metal in a microwave, sometimes. Sometimes metal, or aluminum foil, in a microwave can cause arcing (sparks). This occurs when microwaves come in contact with edges or pointy parts of metal. 

So, to answer the question, you can only use metal in a microwave if you have a smooth surface. It’s just better to play it safe and use microwave-safe plastics, glass, and ceramic bowls. There isn’t a benefit that metal offers that cannot be achieved by the other types of bowls. 

17. Not All Foods Can be Safely Microwaved

As I’ve mentioned earlier, not all foods can be microwaved. In addition to eggs, here is a brief list of foods that should not be cooked in a microwave.

  • Chili peppers
  • Breast milk
  • Leafy greens
  • Grapes
  • Foods with zero water properties

If you are unsure the food you are cooking is microwave safe, perform a web search. 

18. Regulated Since 1971

The perception that microwaves are bad for your health began in the 1970s when tests showed that microwave ovens leaked radiation. Based on this new information, the United States Government created a set of rules that all manufacturers must follow when constructing microwave ovens. 

You’ll be happy to know that the federal government didn’t stop monitoring the microwave oven industry. Different parts of the government are continuing to develop rules to make the microwave oven better.  

One of the most recent rules is on test procedures for microwave ovens, initiating data collection, and a Request for Information. In addition, the general public has the ability to comment on the proposed changes. 

19. Safe for Pacemakers

Another misconception is that microwave ovens have an impact on working pacemakers. While this may have been true many years ago, this is no longer the case. 

Pacemakers are devices that are placed inside the body and generate electrical impulses to contract the heart and help regulate the heart. 

20. Approved by the World Health Organization

Here is what the World Health Organization (WHO) has to say about microwave ovens:

When used according to manufacturers’ instructions, microwave ovens are safe and convenient for heating and cooking a variety of foods. However, several precautions need to be taken, specifically with regards to potential exposure to microwaves, thermal burns and food handling.

Electromagnetic fields & public health: Microwave ovens, World Health Organization

WHO goes on to say:

The design of microwave ovens ensures that the microwaves are contained within the oven and can only be present when the oven is switched on and the door is shut. Leakage around and through the glass door is limited by design to a level well below that recommended by international standards. However, microwave leakage could still occur around damaged, dirty or modified microwave ovens

Electromagnetic fields & public health: Microwave ovens, World Health Organization

Finally, WHO goes on to dispel the thought that microwaves are radioactive:

Misconceptions: To dispel some misconceptions, it is important to realize that food cooked in a microwave oven does not become “radioactive”. Nor does any microwave energy remain in the cavity or the food after the microwave oven is switched off. In this respect, microwaves act just like light; when the light bulb is turned off, no light remains.

Electromagnetic fields & public health: Microwave ovens, World Health Organization

21. Magnetrons Do All The Work

The magnetrons inside of your microwave creates the microwaves that heat you food. This process occurs when the magnetron creates radio waves (another interesting fact, these waves range between 1 millimeter and 30 centimeters in length.

Electromagnetic waves are created when the radio waves resonate with electrical energy. Articles that I’ve read describe creating microwaves is like combining the process of making a TV picture and how a flute works.  

22. There are Three Types of Microwaves

Everyone’s aware of “regular” (solo) microwaves, but there are actually three types of microwaves. The three types are solo, convection, and grill microwave. here is a brief description of these three microwaves.

Solo: these are the microwaves you will most likely see at your home, office, or school. Usually, they include a digital display and standard features like express cooking, one-touch cooking, and defrost.

These microwaves are great for cooking leftovers, beverages, rice, and defrosting frozen food. These microwaves are the cheapest of the three types. 

Grill: these microwaves are a set up in class when compared to solo microwaves. Grill microwaves can do everything solo microwaves can do and simulate the cooking look and feel of an outdoor grill. 

Grill microwaves can cook everything solo grills can cook and can safely cook meat. Usually, the grill is a function that you can turn on and off at the press of a button. Also, you can microwave and grill food at the same time. Finally, these microwaves are more expensive than solo microwaves but are less expensive than convection microwaves.  

Convection: convection microwaves combine the benefits of convection cooking and the benefits of microwave cooking. Convection microwaves are different than grill and solo microwaves because these microwaves heat the microwave box and no the food inside of the box.

Fox example, you can set your convection microwave to a temperature of 400 degrees. For this reason, you can bake cookies, cakes, and brownies. 

Convection microwaves are the most expensive of the three microwave types.

23. Waters, Fats, and Sugars

As I’ve noted above, water molecules inside of food are responsible for microwave cooking. But, did you know foods that have a high amount of fats or sugars are heated less and may be responsible for the difficulty in heating these types of foods? 

24. Commercial Microwaves are very Different than Domestic Microwaves

There are a number of differences between domestic and commercial microwaves. These differences include price, features, watts, size, and convenience. The biggest difference between the two is price. On average, domestic microwaves cost $250. Commercial microwaves, however, cost 4 times as much as domestic microwaves. Below is a brief comparison between the two microwaves.  

Features: another major difference between commercial and domestic microwaves is the turntable. Most domestic microwaves include a glass dish that turns when the microwave is running. Commercial microwaves, for the most part, don’t include the turntable. Most commercial microwaves feature a flat ceramic bottom.

Another feature difference between the two microwaves is the finish. Most domestic microwaves are finished with a hard plastic. However, commercial microwaves are usually finished with stainless steel. Stainless steel is the industry standard for commercial resturants. 

Watts: another difference between commercial and domestic microwaves is the included watts. Domestic microwaves have a wattage range of 550 – 1500. Commercial microwaves can have a wattage as high as 3,500. The wattage has a direct impact on the length of time it takes to cook food.

The higher the wattage, the faster the food will cook. If it takes minutes to cook food at 900 watts, will take seconds to cook the same food with 3.500 watts.

Convenience: Another big difference between commercial and domestic microwaves are the convenience features. Most commercial microwaves have programmable buttons for fast cooking. Using a flash drive, you can program the watts, time, and other features that may be included. 

Most domestic microwaves do not includ programable buttons. These microwaves have express and one-touch cooking. 

25. Tappan, the First Microwave Maker

While Raytheon, the company Spencer worked for while inventing the microwave oven, was first to hold the patent for a microwave, Tappan was the first to create microwaves for home use. The first microwave released by Tappan was created in 1955.

Tappan, an Ohio based company, also claims responsibility for the first electric ignition for gas ranges (1960’s), single unit conventional range and microwave oven (1965). 

Eventually, Tappan became a subsidiary of Electrolux. While you no longer see the name Tappan on the website, you do see the familiar name of Frigidaire. 

26. Radiation Control for Health and Safety Act

The Radiation Control for Health and Safety Act of 1968 became effective October 18, 1968 by the US Congress and it set performance standards for “electronic products of electromagnetic radiation or radiation emissions.” This act established “provisions involving research and development programs for the studies of electromagnetic shielding, ionizing radiation, non-ionizing radiation, and exposure assessment to humans.”

Tips from the Food and Drug Administration

While microwaves are generally safe to use, the Food and Drug Administration (FDA) has a few tips to help ensure your safety. Below are those tips

Follow the manufacturer’s instruction for recommended operating procedures and safety precautions for your oven model.

Use microwave safe cookware specially manufactured for use in the microwave oven

Don’t operate a microwave oven if the door does not close firmly or is bent, warped, or otherwise damaged. 

Stop using a microwave if it continues to operate with the door open

Don’t stand directly against an oven for long periods of time

Some ovens should not be operated when empty. 

Regularly clean the oven cavity, the outer edge of the cavity, and the door with water and a mild detergent. A special microwave oven cleaner is not necessary. Be sure to not use scouring pads, steel wool, or other abrasives.

Microwave Oven Radiation, US Food and Drug Administration


There are the 26 microwave facts. Take these newly learned facts and stump your friends and neighbors!

How many did you know? How did you stumble upon these microwave facts? Are there any facts that I missed? 

Leave a comment below!

Additional Questions

What is the most common use for microwaves today?

The most common use of microwaves is reheating food and cooking snacks like popcorn. In addition, microwaves are also used for cooking frozen meals and defrosting frozen meat. Finally, many people use microwaves for warming up beverages. 

In addition, microwaves can be used to cook just about anything an oven can cook. Microwaves include features like convection and grill cooking to emulate cooking in a microwave.

How many years does a microwave last?

I was surprised to find out that microwaves have an average lifespan of 9.5 years. The lifespan will vary based on the usage, how clean you keep it, and the environment it is kept in.

Should food be covered in a microwave?

Yes, it is best practice to cover your food while using a microwave. One of the man reasons you should use a cover is to prevent food splatter. Food splatter is very difficult to clean up. 

You can cover your food with a variety of items including plastic “microwave safe” plate covers or paper towels. I prefer using a plate cover because they can be reused, they are dishwasher safe, and they don’t meld into your food. Plate covers may also help with cooking the food.

Is it bad to eat microwaved food?

Eating microwaved food is no worse than eating food cooked on a stove or in an oven. Recent studies show that there are no ill effects to cooking food in a microwave.