Except for advances in moisture sensors and convection cooking boasted by some newer models, microwaves haven't received the volume of updates or attention of other kitchen appliances. The few updates they have received, however, have created great disparity in prices. For example, I can go to my local superstore and find a countertop microwave for about $60. I can also order one online and pay more than $1,000.
With that spectrum in mind, the Sharp R-820JS' $289.99 price tag isn't so shocking. However, as our basic expectations of microwaves involve reheating leftovers or frozen meals and making popcorn, that very price range raises some questions. While it is certainly not the most expensive in the category, I would hope that, for $290, the Sharp would perform better than the bargain, $60 model. For $290, I expect to be wowed.
It gets it right about half the time.
If you completely ignore this model's presets, the Sharp R-820JS performs adequately. It reheats as well as any of its competitors, but presets are important features, so we cannot ignore them in our analysis. With this model, many of these presets resulted in epic failures. These shortcomings became all the more obvious when we compared the Sharp's inconsistent presets with the presets on the rest of the models in our test group, like the Whirlpool WMC50522AS, which boasts far more consistency in that regard.
The design of the R-820JS is, for the most part, what you would expect from a microwave. It features a silver-colored metal exterior and a stainless-steel interior. It would look more durable and less inexpensive if it had a stainless exterior like the Panasonic NN-SD997S does, or, at the very least, if it had a stainless-steel front or trim.
The Sharp is the smallest microwave in this initial test group by a fairly wide margin, with an interior of only 0.9 cubic feet and a 12.75-inch carousel. That internal measurement isn't the best indicator of usable space, however, when you consider that the next-biggest unit, the Amana AMC2166AS, has a 1.6-cubic-foot interior, but a carousel that is only .025 inch larger.
If the Sharp is a respectable size for a small-to-midsize countertop microwave, it pales when you compare it with larger microwaves, like the 2.2-cubic-foot Whirlpool and the Panasonic, both of which boast 16-inch-plus turntables.
I'll be honest: next to the other microwaves in our test group, the Sharp doesn't look as if it should be the second most expensive one. The R-820JS isn't a bad-looking microwave, but the display is unreadable unless you're standing right in front of it, and the buttons look like they belong on a toy microwave rather than a real one. If you're buying a microwave for looks alone, unless you like the look and feel of a grown-up Easy-Bake Oven, this probably isn't the unit for you.
For more practical-minded buyers, it's the guts of the machine that are more important. Here's where that spotty performance I mentioned earlier will be an issue.
We devised a battery of tests to examine the core features claimed by each microwave's manufacturer. We also tested the functions we thought might be useful for the average consumer.
As a baseline, we tested how long it would take each microwave to bring a cup of water to a rolling boil. As it's a lower-wattage microwave, the Sharp took longer than the other models, requiring 3 minutes and 30 seconds, compared with 2 minutes and 20 seconds from the higher-powered Whirlpool.
We then completely disregarded the directions of every popcorn manufacturer, and tested the popcorn preset.
The Sharp's popcorn preset is, in a word, abysmal. A 3.2-ounce bag of popcorn contains, on average, 448 kernels. In all of our preset test runs, Sharp only popped an average of 36 kernels. That's popping efficiency under 10 percent. It's as if Sharp didn't account for its own microwave's lower wattage.
I then made a bag of popcorn according to the instructions on the popcorn box. This method produced 69 unpopped kernels, a number much closer to what you would expect and on par with the performance of the Panasonic's preset. The Sharp can make popcorn well enough, you just can't use the preset to do so.
Going farther down the preset rabbit hole, I tested the potato preset function. Rather than using sensors like the Panasonic, the Sharp asks for the number of potatoes you plan to cook and calibrates its time accordingly. I ran this test three separate times, each with an Idaho potato ranging in weight from 11.5 ounces to 14.3 ounces.
The Sharp's preset allotted 5 minutes of cooking time for one potato, plus 5 minutes of resting time. The result was two potatoes that were greatly underdone in the center or, in the case of the largest potato, almost raw. The Amana also asks for the number of potatoes, rather than their weight, but it cooked them more thoroughly.
Presets that determine cooking time based on a number of items rather than by weight seem like a design flaw for microwaves like the Sharp that lack a moisture sensor, especially when the foods in question, like potatoes, lack uniformity.
I'm not sure even a sensor would help the Sharp, given that its presets didn't perform much better when it came to frozen dinners. We tested Stouffer's single-serving lasagna and macaroni and cheese, the former for its density, the latter for the fact that it's fairly representative of the category of frozen dinners.