“What is microwave radiation? Is it dangerous? Are microwaves safe?” We see these questions a lot, so let’s clear it up once and for all: this type of electromagnetic radiation can be dangerous at high levels, but we’ve been using microwaves for decades, and it’s never been a problem. This is because, from the mesh door to the locking mechanism, microwaves are specifically sealed to prevent radiation from escaping, and the design works really, really well. However, if your oven door is damaged or if you think something is wrong, call a contractor and have them test radiation levels. It only takes a few seconds, and then you’ll know for sure.
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. 

Microwave ovens heat food without getting hot themselves. Taking a pot off a stove, unless it is an induction cooktop, leaves a potentially dangerous heating element or trivet that will stay hot for some time. Likewise, when taking a casserole out of a conventional oven, one's arms are exposed to the very hot walls of the oven. A microwave oven does not pose this problem.
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]
Reviewers can’t contain their delight about this microwave’s Genius Sensor, which automatically adjusts the time and power based on the food type. “It feels very futuristic to press the Sensor Heat and let the microwave figure out on its own how long it should cook for. Most of the time, it’s dead-on, too, which is nice,” praises one commenter. “It’s pretty much impossible to overcook something,” writes another. Others note they “have had nothing boil over” and it “cooks super evenly. The days of half-molten-half-frozen food are gone.” Its modern exterior is another strong selling point. “The stainless steel looks very sleek and nice and will fit in with most kitchens,” one says.
Updates writer Eleanor Ford has used a secondhand Toshiba EM925A5A-BS for about seven months now. Even with the previous life of this microwave, our pick has lived up to its reputation. “It’s never failed to do what I expect a microwave to do, heats evenly, doesn't scorch, and is significantly more quiet than any other microwave I’ve used (including my parents’),” Eleanor said. They also noted that the small size allows the microwave to sit on a shelf rather than take up valuable counter space. Eleanor also said that the only notable downside is that they find it difficult to locate the kitchen timer button.
The GE JES1656SRSS used to be our main pick, but has been discontinued. Its replacement, the new GE JES1657SMSS, did well in our tests overall. However, we found that at 1.6 cubic foot, it’s too big for most things you’re ever likely to cook or reheat in a microwave. That said, this model would be a good option for anyone wanting a unit large enough to fit a 9-by-13-inch casserole dish. Like most microwaves we tested, it didn’t defrost meat well, and it lacks a control to silence the beeping.
Closed containers, such as eggs, can explode when heated in a microwave oven due to the increased pressure from steam. Intact fresh egg yolks outside the shell will also explode, as a result of superheating. Insulating plastic foams of all types generally contain closed air pockets, and are generally not recommended for use in a microwave, as the air pockets explode and the foam (which can be toxic if consumed) may melt. Not all plastics are microwave-safe, and some plastics absorb microwaves to the point that they may become dangerously hot.

The Toshiba microwave is covered by a one-year warranty, and the claims process is better than what most manufacturers offer. Typically they require you to ship the unit to and from a service center at your own cost, which likely costs as much as or more than the microwave itself. If anything should go wrong with the microwave under warranty, Toshiba will not repair the unit. Instead, they’ll issue you a refund check, which, according to the representative we spoke to, can take anywhere from four to eight weeks. Just know that you’ll need to provide your original receipt, the cut power cord from your unit, and the model number label in order to receive the refund. Contact Toshiba’s customer support center for more information.
This invention relates to heating systems for dielectric materials and the object of the invention is to heat such materials uniformly and substantially simultaneously throughout their mass. ... It has been proposed therefore to heat such materials simultaneously throughout their mass by means of the dielectric loss produced in them when they are subjected to a high voltage, high frequency field.