Why Do Microwave Ovens Get Hot On The Inside And Outside?

Microwave Ovens

Last Updated on August 8, 2023 By Emma W. Thomas

Microwave ovens get hot on the inside and outside due to the heat generated during cooking. Microwaves emit electromagnetic waves that heat food and surfaces within the oven, causing the interior and exterior to become warm.

Why Do Microwave Ovens Get Hot On The Inside And Outside?

Microwave ovens are a staple feature in most modern kitchens worldwide. They offer convenience and efficiency, especially when it comes to heating or reheating food. However, some people may wonder why microwave ovens get hot on both the inside and outside. Here, we provide an explanation.

  1. Generation of Micro Waves The primary role of a microwave oven is to generate microwaves, a type of electromagnetic wave. The microwaves generated in the oven are absorbed by the water molecules in the food, causing them to vibrate. This action produces heat, which subsequently cooks or warms the food. The heat generated inside the oven can naturally make the inner walls of the microwave oven warm.
  2. Heat Absorption The materials used to construct microwave ovens can absorb some of the microwaves generated. Consequently, this absorption warms the oven’s interior surface and leads to a rise in the oven’s internal temperature, ultimately causing the outside to also get hot.
  3. Non-Uniform Heating Microwaves do not uniformly heat the food. Some spots may be hotter than others, leading to heat accumulation within certain regions. This heat disparity can eventually radiate to the walls of the oven, thereby warming it up.
  4. Inadequate Ventilation Microwaves often get warm on the outside when they lack proper ventilation. How hot the appliance becomes can depend on its surroundings. If a microwave oven is placed in an enclosed area, it may lead to overheating of the outer part of the oven.
  5. Heavy Duty Use Using a microwave oven continuously for a long period can also make both the inside and outside hot. Overuse might increase internal temperatures, causing the outer part of the oven to heat up.
  6. Inefficient Insulation Some models of microwave ovens come with insufficient insulation. Although insulating materials are generally installed between the internal and external walls of the oven, inefficient or worn-out insulation may cause the external part of the oven to heat up.

Is Food Safe In A Microwave Oven?

Food safety is a vital health topic. Though there is no such food safety issue in a microwave oven, yet there is one thing you can supervise while cooking in it. The heating rate of a microwave oven depends on its power rating and water content, thickness, and amount of food you heat. 

Sometimes the microwave energy fails to penetrate inside a thick layer of food and thus results in unevenly cooked food. The uneven distribution of heat will fail to kill all the potentially harmful microorganisms.

Do The Microwave Oven Foods Have The Same Nutritional Values As A Conventional Oven

Microwave-ready foods are both safe and possess the same nutritional value as they have in a conventional oven. The fundamental difference between these two ovens is that microwave energy penetrates deeper into the food. Hence, this helps to minimize the overall cooking time.

How to Do Microwave Ovens Work

Generally, a household microwave oven functions at 2450 MHz frequency with a power ranging from 500 W to 1100 W. Magnetron is an electronic tube that helps to produce microwaves. When you switch on the oven, the microwaves disperse in the oven cavity. 

Then it reflects them by a stirrer fan to propagate in every direction for the food to absorb.

The heat uniformly distributes in the food while rotating on a turntable. Then the water molecules also vibrate after absorbing the microwave energy. After this, the friction between the molecules results in heating the cooked food.

The microwaves do not directly heat a food container. The container usually gets warmth after coming in contact with the heated food.

It is better than microwave oven users to read carefully to comply with the instructions of the manufacturer as a new oven can vary widely in its design and operation.

Can Microwave Ovens Cause Cancer?

Absolutely not. A microwave oven cannot cause cancer. To date, no research proves that using microwave ovens can develop cancer.  

The microwave oven uses electromagnetic energy to prepare food. The energy heats the water molecules. Whether you heat or cook food in a microwave oven, they do not become radioactive. Thus, it will not damage DNA and cause cancer.

But there are a few precautions that a microwave oven user can take. 

  • Make sure that the microwave door is shut correctly.
  • Follow the guidelines of the manufacturer.
  • Use only those containers that are microwave safe.
  • Avoid using take-out containers or plastic wraps in the microwave oven. They can melt or leak into the food.
  • While cooking, stir the food occasionally at an optimum temperature.
  • You may also lift or open the lid of the container while microwaving the food.

Can The Radiation Of The Microwave Oven Cause Harm

Cooking or heating food inside a microwave oven is extremely convenient thanks to its incredibly fast preparation time. But some people think that it can generate dangerous radiation and reduce healthy nutritional values.

Well, this is because microwave ovens stimulate electromagnetic radiation. The negative connotation of radiation gives air to this type of myth.

However, this radiation is not the same radiation as nuclear disasters and atomic bombs. The ovens produce non-ionizing radiation, which is somewhat similar to the radiation from the mobile phone. 

Also, microwave ovens come with metal shields and screens on the window that helps to prevent radiation from leaving the oven. So, there is no chance of any risk or harm happening.

Only to be on the safer side, refrain from thrusting your face against the microwave window. Also, keep your head at least 30 cm away from the microwave oven. This is because the power of radiation decreases shortly with the passing distance.

In addition, keep a check on the microwave oven. Make sure that it is in good condition. If it is an old one or got damaged, then consider buying a brand new microwave oven. Remember, safety comes first and then everything else.

Microwave Ovens Watt cooking power & Prices

SerialNameWatt cooking powerPrice
01Toshiba EM925A5A900 Watts80$
02GE JVM31601000 Watts309$
03Toshiba EM131A5C-BS1100 Watts120$
04EM720CPL-PMB700 Watts64$

What Are The Advantages And Disadvantages Of Microwaves?

There are various advantages and disadvantages of a microwave oven. To check them out, read the table given below.

Serial NumbersAdvantages of a Microwave OvenDisadvantages of a Microwave Oven
1.A microwave can effectively preserve more nutrients than a stovetop. A microwave oven does not allow frying food. Moreover, the food becomes soggy or dry out becoming hard.
2.Microwave cooks and heats food within a very short time.A microwave oven uses friction to prepare food. So, it can shrink or change form and appear in poor texture after complete cooking.
3.Microwave ovens use short-wavelength electromagnetic waves to generate water molecules vibration at a high frequency.The cooked food cannot come out brownish and crispy.
4.The user can set time and relax. The microwave oven will automatically stop cooking after the completion of the allotted time.The user cannot use metal as it may result in arcing. Arcing can further cause an awful smell, smoke, and fire.
5.It can defrost any frozen food items within no time.The user cannot use any plastic container. Using the wrong plastic container can emit harmful toxins in food, melt or burn the container.
6.Microwaves consume less oil to cook food. Thus, making this an ideal appliance for fitness freaks.Microwaves have a limited capacity that makes it challenging to cook a complete meal.

Are Microwave Ovens Risky?

A microwave oven is not ideally risky, but it has some electrical components inside that can be hazardous if you take them apart. The microwave oven door comes with a metal that prevents microwaves from evading the oven when it is still operating. 

When the oven stops, the microwaves disappear rapidly, and so there is no danger when you open the door. Nonetheless, if you see a hole in the door or the microwave functions abnormally, it can turn into a significant hazard.

Also, follow the instructions in the manual. Do not insert metal objects like a fork or a metal plate in the microwave oven as it has the potential to cause arcing. Arcing is sparks that can damage your oven. 

How To Increase The Life Of A Microwave Oven?

There are a few measures that you can take to increase the longevity of a microwave oven. 

1. Be Quick To Clean

Do not waste time and clean up the microwave oven as soon as your meal is ready. Take a sponge and soak in the spills shortly after they occur. Remember, if you leave pieces of food behind in the microwave oven, then it can consume some of the microwave energy. Further, when you turn on the oven again, it will create a hotspot that can defect the interior.

2. Avoid Scratches

Take proper care to avoid leaving scratches on the protective mesh inside the door. This mesh prevents the microwaves from breaking out and zapping the user.

3. Turn On The Exhaust Fan. 

Do not forget to turn on the exhaust fan when cooking on the cooktop. This will help to avoid collecting moisture from the cookware on the electronic parts of the microwave. Furthermore, it will expand its lifespan. However, if humidity collects, then scrub or simply wipe it off with a soft cloth or paper towel.

4. Avoid Slamming The Door 

Usually, a microwave oven door has three safety interlock buttons. Sometimes, four safety buttons are disabled when you open the door of the oven. 

These safety buttons should stay in line with their corresponding latches while closing the microwave door. If you slam on the door, it can break the components as they are very delicate. 

5. Never Run An Empty Microwave Oven

When there is nothing inside the microwave, there is also the absence of water molecules to excite. Simultaneously, the unit may overheat rapidly and cause burn marks in the interior.

6. Avoid The Use Of Metal

Unlike microwavable plastics and glass, metal reflects microwaves and restricts them, passing them to the food. So, when you put a metal utensil or fork in a microwave oven, it may cause arcing.

Moreover, if the metals touch the sides of the interior, the fire sparks can burn and leave a hole in the cavity wall. Sometimes, these types of damages are unrepairable. 

This is why most manufacturers recommend using aluminum foil in a microwave by folding it tightly around the food.

7. Preset The Cooking Time

It is always better to preset the cooking time to avoid food from overcooking or spattering inside the oven. Be careful to set the cooking times. An unmindful preset such as setting time at 20:00 instead of 2:00 can cause damage to the microwave oven.

8. Always Take The Help Of An Expert 

Never attempt to repair the microwave oven by yourself if you are not an expert. There have been reports from the Consumer Product Safety Commission that many people electrocute themselves while they try to repair their microwaves.


A microwave oven is a time-saving kitchen appliance that is safe and healthy to use. It can get a little warm outside for some reason, but if you find something fishy, consult an expert.

In this article, we have burst some myths regarding the microwave oven. So, include them in your daily life without fear and take special care to extend their longevity.