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Sharp Zr309YK Review

An average model at an average price
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Sharp Zr309YK Review (The Sharp ZR309YK.)
The Sharp ZR309YK.
Credit: Sharp
Price:  $110 List
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Manufacturer:   Sharp
By David Wise and Austin Palmer  ⋅  Apr 3, 2017
  • Heating - 40% 6.0
  • Ease of Use - 30% 7.0
  • Defrosting - 20% 4.0
  • Speed - 10% 5.0

Our Verdict

The Sharp Zr309YK is Discontinued as of June 2017
The Sharp is an average microwave that gets the job done. This model only fell a little flat at defrosting by weight, and has a list price that won't break the bank. It costs a bit more than the best value options out there, and performs a little worse. All in all, the Sharp is a middle of the pack, average microwave.
Best of the bunch at frozen burritos
Easy to use
Mediocre at other pre-made frozen foods
Uneven heating

Our Analysis and Test Results

The Sharp finished in the middle of the pack for this review and has a reasonable price. It definitely wasn't our favorite, but we weren't upset by it. It is very easy and convenient to use and does a decent job at heating up food.

sharp zr309yk - the sharp r309yk.
The Sharp R309YK.
Credit: Jenna Ammerman

Performance Comparison

We did extensive research and bought the top 10 microwaves currently available to help you find the best. In total, we spent over 150 hours researching and testing to determine our results. We split our testing process into four weighted metrics: Heating, Ease of Use, Defrosting, and Speed. The following sections detail exactly how the Sharp did — what it did well, and where it fell a little short.

sharp zr309yk - the sharp was a runner-up for best lasagna.
The Sharp was a runner-up for best lasagna.
Credit: Austin Palmer


The Sharp did slightly above average in our set of heating tests, earning a 6 out of 10. We made an individual serving of lasagna, a frozen burrito, a chicken pot pie, a Hot Pocket, a sample plate of leftovers in each model, comparing the performance using an array of cooking thermometers to assess uniformity. We also used molten chocolate to create a heat map for each model, looking for uneven heating patterns.

The Sharp actually did the best out of the entire group at heating up a frozen burrito, having the lowest average temperature difference. All portions of the burrito hit the necessary temperature as stated by the package directions, and were heated extremely close in temperature, with the average variation being only 2.2°F.

The Sharp continued to do well when it came to heating up a small serving of lasagna, tying for the second-best score of the group. We followed the package directions on the lasagna, then compared the results with the thermometer grid. All of the different regions hit the requisite 160°F, with the average temperature variation being 5.3°F.

However, this model did a subpar job at reheating the plate of leftovers. We made an identical plate of mashed potatoes., chicken tenders, and green beans for each model, then reheated using a dinner plate reheat setting, or something similar. We checked the temperature between each type of food, as well as within it, looking for even heating. In the Sharp, the green beans were much hotter than the rest of the food items, and there was a drastic heating inconsistency between the left and right sides of the mashed potatoes. One side was much warmer and dried out, compared to the lukewarm opposing side.

sharp zr309yk - the leftovers were very unevenly heated in the sharp.
The leftovers were very unevenly heated in the Sharp.
Credit: Austin Palmer

The Sharp continued its downward trend in our next test, doing an abysmal job at heating up a chicken pot pie. It tied for the second-worst score of the entire group, with the center of the pot pie failing to reach the necessary temperature of 165°F, falling over 10°F short. There was also a substantial amount of temperature variations, with the average being 16.8°F, due to the sides being much warmer than the center. The crust also failed to crisp up, becoming very soggy after heating.

sharp zr309yk - the sharp failed to heat the pot pie to the minimum temperature in...
The Sharp failed to heat the pot pie to the minimum temperature in the center.
Credit: Austin Palmer

This model did redeem itself a bit in the final two tests, heating up a Hot Pocket and the chocolate heat map. The Sharp tied for the third-highest score for its Hot Pocket performance, heating the sandwich up evenly and above the required temperature., with only 7°F average temperature variation between the left, right, and center sections.

sharp zr309yk - the sharp exceeded the stated minimum temperature and did an alright...
The Sharp exceeded the stated minimum temperature and did an alright job at heating the Hot Pocket evenly.
Credit: Austin Palmer

The Sharp did an excellent job in the heat map test, tying with the Panasonic NN-SD745S for a perfect score.

sharp zr309yk - the chocolate was totally melted and not burnt in the heat map.
The chocolate was totally melted and not burnt in the heat map.
Credit: Austin Palmer

We spread a thin layer of molten chocolate on a carefully trimmed piece of parchment paper, then let it cool. We heated it for a minute and looked for even melting across the disc, with no noticeable cool spots or burnt spots.

sharp zr309yk - the sharp was the second easiest to use of the entire group.
The Sharp was the second easiest to use of the entire group.
Credit: Jenna Ammerman

Ease of Use

We evaluated the convenience and how easy these products were to use for this metric, testing aspects from the effectiveness of the popcorn button to whether or not the microwave would slide around on the counter when the door was opened or closed. The Sharp did very well, earning a 7 out of 10, tying for the second-highest score of the entire group.

This model had some of the most effective preset buttons of the bunch, creating a great bag of popcorn and a baked potato using the “Popcorn” and “ Potato” buttons. The popcorn tasted great and wasn't burnt at all, though it did leave behind more unpopped kernels than other models.

sharp zr309yk - the sharp left behind a decent number of kernels, but didn't burn...
The Sharp left behind a decent number of kernels, but didn't burn any when using the popcorn preset.
Credit: Austin Palmer

The potato came out great as well, though one side was just a tiny bit firmer than desired. This ranked just below the Oster in terms of quality, and had about an average amount of temperature variation across the left, right, and center portions of the potato, about 5°F.

sharp zr309yk - the sharp produced a decent baked potato.
The Sharp produced a decent baked potato.
Credit: Austin Palmer

This model didn't have a light that would turn on when the door was opened, but it did have a great set of quick buttons — a feature that we ended up using the most. It has a “+30 Seconds” button that will automatically start the microwave, as well as use the keypad as a set of quick buttons. For example, pressing “1” automatically starts the microwave for one minute. The Sharp can't run a separate kitchen timer when you are heating food, though it does have one.

sharp zr309yk - the + and - buttons would add or subtract 10 seconds from the time...
The + and - buttons would add or subtract 10 seconds from the time left on the clock.
Credit: Jenna Ammerman

The keypad was alright on the Sharp and did have a unique feature. There were “+” and “-” buttons that would add or subtract 10 seconds from the time when it was running.


This metric tested how well the defrost by weight function worked on these products. We defrosted a 1 lb roll of ground turkey and a frozen muffin by weight, then evaluated the quality of the finished product to determine the scores. The Sharp didn't do the best in this metric, earning a 4 out of 10 — tying for the lowest score of the group.

This model only defrosted 7 ounces of the ground turkey, and it was much more difficult than other models to break apart the remaining log. It did notify you to flip the meat halfway through.

This model has a defrost by time function, as well as a defrost by weight, though the defrost by weight is a little different than other machines. It only has preset weights for different food types, such as meat, poultry, or fish. This is why we ended up defrosting the frozen muffin using the fish setting, as the weight most closely matched. The Sharp did about average, heating the muffin throughout on the inside, but superheating the bottom on the outside.

sharp zr309yk - the sharp did an alright job in our speed test, earning a 5 out of 10.
The Sharp did an alright job in our Speed test, earning a 5 out of 10.
Credit: Austin Palmer


This final test was to determine just how fast these quick-cooking appliances were. Our testers heated a beaker full of 250 mL of water for 30 second and recorded the temperature change. The Sharp did about average, earning a 5 out of 10 for its 34°F temperature boost.


The Sharp is a slightly below average microwave at a slightly above average price, definitely not the best value, but not the worst.


The Sharp is a middle-of-the-road microwave that makes outstanding frozen burritos, but was essentially mediocre across the board. It might be a good choice for those that only want to make frozen burritos, or if it's on a fantastic sale.

David Wise and Austin Palmer