Picture of the Panasonic Inverter NN-SN778 Microwave Oven, unpacked and sitting on counter.

Countertop Microwave Oven Panasonic Inverter NN-SN778 Review

The Panasonic Inverter  Countertop Microwave Oven, model NN-SN778, comes packed with high power output for a residential microwave in a small package.

We paid approximately $150 for ours several years ago, and it has performed reliably since then.  Due to its higher-than-typical amounts of microwave energy for a 120-volt oven, food cooks in shorter times than are found in typical recipes and preparation instructions on packages.  But it’s nice having the extra power for those “stubborn” tasks like boiling the water fro macaroni and cheese.

Picture of the Panasonic Inverter NN-SN778 Microwave Oven, unpacked and sitting on counter.
Panasonic Inverter NN-SN778 Microwave Oven, unpacked and sitting on kitchen counter.

Advantages, Features and Functions, Benefits, and Pros

The Panasonic Inverter Microwave Oven offers most of the benefits and features that one would expect in a 2014 model; yet this one is now several years old.  The most notable ones for us include the following:

Users guide and owners manual included.  The NN-SN-778 oven comes bundled with an extensive Operating Instructions pamphlet, that completely explains fully its features, offers poplar recipes for defrosting, heating, and cooking of popular foods, and provides tips for the safest installation, operation, and cleaning of this appliance.

Stainless steel trim.  Stainless steel front panel finish, for a markedly contemporary look and cinchy cleanup.

Not too big.  Fits well on even modestly sized kitchen countertops.  See picture below for an example.

Membrane-style control panel buttons.  The more commonly used buttons however, are the more traditional momentary contact, spring-loaded ones; presumably, this is done to increase overall durability of the control panel.

Adequately sized AC cord.  Thick power cord in the rear of the unit, for easy concealment and connection.  Remains cool even during long periods of cooking with highest power setting.

Carousel glass tray.  Extra large, encompassing rotating glass tray inside.

1250 watts of food defrosting / cooking / heating power.  Plenty for cooking pasta and macaroni.

Long maximum cooking time.  Maximum of 99 minutes and 99 seconds per single stage of cooking. But if you need more time, you can either program multiple stages, or enter more cooking time when this 1:40:39 time runs out.

Interior light.  Illuminates the rotating food inside plentifully.

Yellow LED clock and function display.

Fairly quiet.  Operates with low to moderate noise levels, with plenty of fan power and venting.   All you hear is a gentle hum and whirring of the internal fan during operation.

Adjustable cooking power level.  Variable power output setting, in ten-percent increments, from full power, down to zero power.

Audible feedback.  The oven beeps, confirming button and pad presses and completion of cooking.  It sounds when oven shuts off after cooking is complete.

A cooking sensor, that “senses” when cooking food has reached the desired doneness. When used, the sensing ability removes the need to actually set a cook time.  See below for how this is used.

Popcorn button; that immediately configures microwave settings for optimum popcorn popping.

Plain English notifications on display.  The display communicates status messages in actual text to the user, and the speed with which those messages scroll across the little screen can be controlled in the setup options.  Messages can be configured to display in either English, French, or Spanish among others.

A child lock, to prevent unauthorized / unsupervised operation by children.

Basic usage prompts   can be disabled as one’s skill level with the oven rises.  With child lock activated, the microwave will not operate.

Demo mode, allows for in-store demonstration of how the unit works without actually turning on the microwave transmitter inside.

Inverter Turbo Defrost   feature, that allows for programmable defrosting of food by weight.  Tips on safely defrosting foods of various types are included in the Operator’s Guide. A programmable stand time is also included, for foods that require a certain amount of time after the ON part of the defrost cycle ends on this oven. Stand time describes how long you allow the food to stand before beginning the next phase of its preparation process.  The rest of the defrosting happens during this time, and the application of standing time helps ensure that the food does not begin to cook during defrosting.

Also a timer.  The built in clock and display can also function as a kitchen timer.  A so-labeled for this is provided.

The clock keeps very accurate time, drifting only a second or two in a several-month-long period. It can be set to display daylight savings time, without actually adjusting the current hour value.  Time display can be disabled should you desire not to see it.

English or metric support.  The weights of foods can be set to English or metric system (Kg or pounds).

Multiple stage cooking. Five stage maximum.  This allows multiple phases of the cooking, where you can adjust the power level of each stage, as well as the time that that stage goes on.

A Keep Warm ability, by adding a keep-warm stage as the last stage of cooking can be programmed.

More / Less button   allows the addition or subtraction of either ten or twenty from the currently-remaining cooking time.

Genius sensor.  Foods can be cooked / reheated with approximately the correct amount of time, using the Genius Sensor reheat / cook feature.  The oven actually senses the amount of heat and steam generated in the food, and can thus, make fairly intelligent predictions about how much longer it will take to completely reheat / cook it.  Opening the door during this mode of operation however, can destroy the accuracy of the sensor, as steam will escape, and not therefore, be accurately measured by the sensor.

A Quick Min   button allows for quick entry of cook time (up to ten minutes).  Once you’ve entered the desired time (via the number of times this button is pressed), press the Start button to begin cooking for the specified interval.

Reliable.  We’ve used ours almost daily for several years, and have experienced no failures.

Generous warranty.  The magnetron is covered against failures for five years.  One year for the rest of the oven.

Cons, Disadvantages, Problems, and Limitations

Can start food to burning.  The higher power is a mixed blessing.  It can work well for heating a wider variety and quantity of foods, but if not adequately attended, this microwave can quickly overheat and set foods on fire.  So use it with caution, please.

Some RFI noted.  Generates small amounts of radio frequency interference (RFI).  Can interfere with computer WiFi, and the oven operates at 2.45 Ghz., within the same frequency range of WiFi devices and some older cordless telephones.  However, we’ve found this microwave to be very well shielded, and therefore, such interference to be minimal to non existent.  This particular issue is not specific to this specific microwave; but the best microwave ovens provide better shielding against this type of RFI.  The NN-SN778 does a good job at containing its radio noise.

No “Add 30 Seconds” button. This feature allows instant programming for highest power, for 30 seconds.  The oven would start running immediately upon the first press of this button, and additional half-minute time blocks are added to the total remaining time, with each additional press of this button.  We prefer ovens with this function.  It’s highly convenient; particularly for short run cooking like when heating a cup of tea or popping a bowl of popcorn. However, the More / Less button accomplishes the same thing, but utilizes 10-second increments rather than 30-second steps.

Not a toy.  This is by no means an “easy-bake” oven.  The additional power over the typical oven that this one utilizes, means that it’s easier to overcook foods.  Foods become overcooked significantly more quickly.  So greater attentiveness during use is necessary.  Not a show-stopping issue though.

No browning feature.  Contains no conventional style oven heating elements.  So the Panasonic Inverter microwave relies exclusively on microwave energy, not heat energy, to do the cooking.

Hard to install rotating tray.  Sometimes, it’s difficult to get the circular glass tray properly centered on the motor hub.  This appears to be caused by the surprisingly small diameter of the hub.  Increasing this diameter, as well as the size of the engaging feet and mating openings on the hub, would seriously reduce this problem.

Most functions are not accessible to blind users.  The addition of an audible speaking voice that enumerates all menus and function settings would be most helpful.

Picture of the Panasonic Inverter NN-SN778 Microwave Oven with its door open, showcasing its interior.
Panasonic Inverter NN-SN778 Microwave Oven with its door open, showcasing its interior.

Our Rating

Our experience with this Panasonic Inverter microwave oven, is a few years, and in that time, it has rarely disappointed us.  It cooks quickly and completely when properly monitored, has more than adequate power for most if not all residential food preparation tasks, and is very reasonably priced.  We paid around $140 for our copy at Walmart.  No kitchen these days should be without a microwave oven, and this one is among the most easy to program, versatile units we’ve owned.  We’d rate it therefore at 96 out of 100 overall.

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Revision History

  • 2015-12-13: Added appropriate tags.
  • 2015-01-10: Revised content.
  • 2014-12-15: Added featured image and tweaked the content.
  • 2014-10-11: Originally published.