For an over the range microwave, you need the right kind of airflow for your setup, and you may need additional features like the ability to control oven range lights. Over the range units are specifically designed for these tasks, but they vary from model to model, so don’t get complacent when buying. Know what you need to keep your stove clear of smoke first!
However, lower-frequency dielectric heating, as described in the aforementioned patent, is (like induction heating) an electromagnetic heating effect, the result of the so-called near-field effects that exist in an electromagnetic cavity that is small compared with the wavelength of the electromagnetic field. This patent proposed radio frequency heating, at 10 to 20 megahertz (wavelength 30 to 15 meters, respectively).[5] Heating from microwaves that have a wavelength that is small relative to the cavity (as in a modern microwave oven) is due to "far-field" effects that are due to classical electromagnetic radiation that describes freely propagating light and microwaves suitably far from their source. Nevertheless, the primary heating effect of all types of electromagnetic fields at both radio and microwave frequencies occurs via the dielectric heating effect, as polarized molecules are affected by a rapidly alternating electric field.
This affordable microwave receives high praises for its compact size. “It works excellently, had a small footprint so it fits perfect on our countertop,” one reviewer writes. “It’s fairly small but very well constructed. Especially if you don’t have tons of space in the kitchen.” While some purchase the appliance for college dorms or small apartments, one reviewer shares it’s a great size for the office: “We needed a microwave that fit in a fairly small space. This one fit the bill. It is used on a regular basis here at work, and we have had no problems with it to date.” While it lacks the bells and whistles of other, more expensive models, such as sensor technology and “softening butter” presets, “if you are looking for a simple microwave, this is it,” writes one commenter.
The Toshiba has an easy-to-use digital interface, with one key feature that helps it stand out from much of the competition: a mute button. Since this model doesn’t stop beeping when you open the door, we appreciated having the option to mute the beeping entirely. The Toshiba also has six preset cooking functions for popcorn, potatoes, pizza, frozen vegetables, beverages, and reheating a dinner plate. It has one-touch start controls from 1 to 6 minutes, and a plus-30-seconds button so you can quickly add extra time. Also, its lock function prevents kids from accidentally operating the machine (you simply hold the stop/cancel button for 3 seconds to lock or unlock the door). This model also has several other features that other microwaves we tested lacked, including a memory function (that saves up to three customized cooking times and power levels) and a multistage cooking function (that allows you to set two different cooking times and power levels to operate in succession), but we don’t think most people will use these often.
The lower temperature of cooking (the boiling point of water) is a significant safety benefit compared to baking in the oven or frying, because it eliminates the formation of tars and char, which are carcinogenic.[49] Microwave radiation also penetrates deeper than direct heat, so that the food is heated by its own internal water content. In contrast, direct heat can burn the surface while the inside is still cold. Pre-heating the food in a microwave oven before putting it into the grill or pan reduces the time needed to heat up the food and reduces the formation of carcinogenic char. Unlike frying and baking, microwaving does not produce acrylamide in potatoes,[50] however unlike deep-frying, it is of only limited effectiveness in reducing glycoalkaloid (i.e., solanine) levels.[51] Acrylamide has been found in other microwaved products like popcorn.
The Panasonic NN-T945SF offers 2.2 cubic feet of interior space and 1,250 watts of power to heat food in less time than much of the competition. “It offers power levels from 1-10 with 10 being the highest,” explained one of our testers, “and I found that even using level 5, the microwave is able to heat the food very quickly and evenly.” Other pluses include the sleek stainless steel appearance and 14 auto cook options. If you frequently use your microwave to cook, steam, or defrost, you’ll appreciate the built-in inverter, which delivers consistent heating power that won’t leave food rubbery or unevenly heated. People find the display and controls to be easy enough to use, but a few online reviewers said they experienced button failure for the door after several years. The microwave is also quite large, so it's not a good choice for small homes.
Many reviewers of this Panasonic microwave oven rave about its power, efficiency, and spacious interior. “We have been totally delighted with this microwave,” writes one. “We have had to scale back cooking times because of the incredible cooking power. The spacious interior and ease of use are just the best.” Another says, “Constant microwave power emission cooks to total satisfaction with no cold spots. Baked potatoes are the best I’ve ever had in my life, and I’m old, smooth, creamy, uniform texture throughout. No overdone skins. Sensor cooking works too. At this price, it’s a steal.” Part of what sets this microwave apart is the stylish stainless-steel front, with several reviewers noting that it “blends in well with a kitchen with stainless-steel appliances and black, as well.”
In our heat map test, the Toshiba produced the most even heating pattern of all the microwaves we tested, perfectly browning the layer of marshmallows from edge to edge. It expertly cooked a baked potato in about 6 minutes, which was average for the microwaves we tried. It also reheated beverages well and perfectly cooked frozen macaroni and cheese. And it made tasty popcorn, with only 5 grams of kernels left unpopped, which was on a par with most of the models we tested. This model allows you to defrost by time or weight, but like most of the microwaves we tested, it didn’t defrost meat well.

Due to this phenomenon, microwave ovens set at too-high power levels may even start to cook the edges of frozen food while the inside of the food remains frozen. Another case of uneven heating can be observed in baked goods containing berries. In these items, the berries absorb more energy than the drier surrounding bread and cannot dissipate the heat due to the low thermal conductivity of the bread. Often this results in overheating the berries relative to the rest of the food. "Defrost" oven settings either use low power levels or turn the power off and on repeatedly - designed to allow time for heat to be conducted within frozen foods from areas that absorb heat more readily to those which heat more slowly. In turntable-equipped ovens, more even heating will take place[citation needed] by placing food off-centre on the turntable tray instead of exactly in the centre, so that no part of the food item will be continuously unheated by the center "dead zone".

Next, we tried defrosting a 1-pound portion of frozen ground beef in each microwave, using the automatic defrost setting on the models that had this feature. Some units gave prompts to flip the meat, which we did. When the time was up, we broke apart each block of meat with a fork to see if it was completely defrosted. None of the microwaves were particularly great at this task. Every model at least slightly cooked the edges of the ground beef we attempted to defrost. (Best practice is to slowly thaw meat in the fridge, or relatively quickly under cold running water.)
The defrost options (varying by type or weight) are ideal if you want to warm something up with the microwave before cooking with the convection setting. If you have a busy kitchen and want multiple ways to cook foods (instead of just nuking the occasional popcorn bag), Cuisinart delivers. About the only thing that it’s missing is the ability to set power levels, but with all these other features, that’s a minor quibble to be had.
Every microwave oven contains a magnetron, which generates microwaves. Those waves are then guided into the oven’s cavity, where they bounce around, rapidly swinging the polarity of charged molecules in foods (particularly water, fats, and sugars) and generating heat. Metal mesh on the door keeps those large-wavelength microwaves from escaping the metal box and cooking you. (This great video uses a disassembled model to explain further.)
You may be a bit limited in your choice of OTR microwaves because you’ll need a model that fits snugly above your stove. Most people also want an appliance that matches their range. And, unfortunately, OTR microwaves are more complicated to install, especially if you haven’t had one before. In these instances, you may need to hire an electrician, which can drive up the overall cost of your new microwave. 
If you really want microwave power levels that function accurately, look for a microwave with an inverter. What is an inverter microwave? Essentially, it uses a different type of microwave production that actually does change the power levels and heating. Set power to 5, and the inverter will make sure heating is at 50%. Other types of microwaves will use a cycling method, where the power is always set to 100% but at level 5 it cycles half as much as at level 10. Inverter technology tends to make power levels much more effective and sensible, but either way it’s important to know what you’re getting into.

If you’re a fan of wall ovens, you may also like the look of built-in microwaves, which are designed to be installed flush with a wall or cabinet so you don't have to give up counter space. However, these microwaves are significantly more expensive than other options, starting at around $300. It’s worth noting that some countertop microwaves have optional kits that allow them to be installed as a built-in, so this may be a way to save some money. Additionally, it’s often complicated to install a built-in microwave, especially if you didn’t have one previously. 
Fast cooking was our top priority — if a microwave can’t prepare a meal speedily, it isn’t the best. Ray Boxman, Professor Emeritus of Electrical and Electronics Engineering at Tel Aviv University, told us microwaves cook fast “because the microwave energy penetrates into the food, in contrast to conventional heating, which only delivers heat to the surface of the food, and a lot of time is needed for the heat to diffuse inward.”
The best size microwave for you will depend on how much space you have available and how much food you'll need to heat up at a time. If your space is limited or you're only heating food for one person, a 0.5 cubic-foot model may be a good choice. If you're furnishing a gourmet kitchen, you may want a 2.5 cubic-foot combination microwave-convection oven.
Over-the-range microwaves give you the convenience of quick reheating without sacrificing counter space. This 1.9-cubic-foot model from Whirlpool is available in multiple colors and finishes, including fingerprint-resistant stainless steel. Featuring 1,000 watts of power, it's also equipped with a 300 CFM ventilation system to keep odors and smoke from your cooktop under control. Customers particularly love the inclusion of the three-speed fan. Reviewers found installation to be fairly straightforward, but some noted that the instructions for all the settings aren't very clear.
Frequently used microwaves need to be cleaned at least once per week, because any food remnants stuck to the walls can get overheated and cause damage to the microwave itself. A simple trick (courtesy of Wirecutter deputy editor Christine Cyr Clisset) is to nuke a bowl of water for a few minutes on high: The steam will loosen most gunk, and you can wipe it out with just a plain paper towel or a sponge. For cleaning the outside of a microwave, Good Housekeeping recommends spraying cleaner onto a towel and not on the actual surface, where it can get into the perforations and damage the internal elements.
It’s a good idea to clean your microwave regularly, even if you clean up spills or splatters here and there. To clean the inside, heat a microwave-safe bowl filled with water and a tablespoon of vinegar (white or apple cider will work) for several minutes. You want the inside to get steamy without the bowl of water to boiling over. Let the mixture cool for a few minutes before opening the door. Then, wipe the inside clean with a paper towel or use an abrasive sponge for any stuck-on food. Remove the turntable and either wash it by hand or in the dishwasher. Use an all-purpose cleaner for the exterior, but spray onto a paper towel or sponge first—not directly onto the microwave—to avoid it getting into the venting system. You should also avoid using bleach in your microwave.
To find the best microwave, we tested 10 microwaves in our Kitchen Appliances and Technology Lab, checking how well they melted cheese, "baked" potatoes, reheated food, defrosted frozen food, popped popcorn, and cooked vegetables. We also looked at their ease of use — controls, opening the doors, view-ability inside, cooking alerts, and cleaning. For models with convection and/or grill capabilities, we tested their ability to roast chicken, bake cake, and broil steak, then noted the surface temperatures. Based on our extensive tests, we've rounded up our top-rated microwaves:
Since this model is particularly affordable, this is a good time to mention that prices can fluctuate based on inventory and other factors. We can’t necessarily guarantee that our listed prices are the rule of law. The good news here is that they may drop and save you even more money! But this Toshiba model still remains one of the most affordable picks we found of the bunch.

Another misconception is that microwave ovens cook food "from the inside out", meaning from the center of the entire mass of food outwards. This idea arises from heating behavior seen if an absorbent layer of water lies beneath a less absorbent drier layer at the surface of a food; in this case, the deposition of heat energy inside a food can exceed that on its surface. This can also occur if the inner layer has a lower heat capacity than the outer layer causing it to reach a higher temperature, or even if the inner layer is more thermally conductive than the outer layer making it feel hotter despite having a lower temperature. In most cases, however, with uniformly structured or reasonably homogenous food item, microwaves are absorbed in the outer layers of the item at a similar level to that of the inner layers. Depending on water content, the depth of initial heat deposition may be several centimetres or more with microwave ovens, in contrast to broiling/grilling (infrared) or convection heating—methods which deposit heat thinly at the food surface. Penetration depth of microwaves is dependent on food composition and the frequency, with lower microwave frequencies (longer wavelengths) penetrating further.[citation needed]