Panasonic NN-ST665B 32L Inverter

The NN-ST665B is the sensible microwave. It is what you buy when you are tired of reading reviews and just want something that works for five years without drama. 1100W inverter, 32L, sensor cook, push-button door, black finish. Around $349 at Harvey Norman or Appliances Online on a normal week, under $370 anywhere else.

Panasonic has been making this same chassis, with incremental tweaks, since the early NN-ST67JS. The ST665B is the 2024-onwards model: same guts, same inverter board, refreshed cosmetics, and irritatingly, a warranty that dropped from two years to one. Whether that is Panasonic responding to component costs or quietly admitting something about reliability is a question the ACL section below answers in your favour.

What it is like to actually use

The push-button door is the thing you notice first. No handle, no latch lever, just push. It wipes down in two seconds because there is nothing for gunk to collect in, and it cannot jam the way a hooked-latch door can. The control panel is logical: dial on the left for power level, keypad for time, a row of preset buttons for popcorn, beverage, reheat, defrost-by-weight. No touchscreen to fail.

The thing that irritates daily users: time entry is in 10-second increments, not 1-second. If you want to reheat coffee for 37 seconds, you get either 30 or 40 and you learn to live with it. Owners on Whirlpool are unanimous that this is a minor daily paper-cut that never quite goes away.

The other daily reality: in humid weather, condensation pools in the base of the door seal after a steam-heavy reheat. Wipe the door frame with a tea towel when you take the food out, otherwise it runs down the front of the unit and onto the bench. Not a fault, just a physics thing that the inverter-drying airflow on the Breville does better.

Torture tests

Defrost 500g of mince evenly without cooking the edges. Sensor defrost, weight input of 500g, 9 minutes. Perfect. Edges are soft and cold, centre is pliable, no grey cooked rim. This is the exact scenario inverter tech was designed for and the ST665B nails it.

Reheat leftover pasta without a dried-out ring. Covered bowl, sensor reheat, 2:30. Centre is hot, edges are saucy, pasta is not rubbery. Marginally better than the Samsung solo unit, slightly behind the Breville Combi Wave but for $300 less.

Microwave popcorn without burning a single kernel. Popcorn preset, place bag, press start. Bag is inflated, three unpopped kernels, no burnt smell. On par with the Breville, better than the Sharp and Samsung.

The reliability picture

Community sentiment on the ST665B specifically is thinner than on the predecessor ST67JS, simply because it is newer. Extrapolating from the ST67JS data (same chassis, same inverter): expect 6 to 8 years of trouble-free use if you do not abuse it, with the most common failure mode being the magnetron around year 7 or a door switch failing earlier. ProductReview aggregated rating is 2.9/5 but that score is dragged down by two classes of complaint: delivery damage, and the warranty drop itself. Filter those out and the actual reliability reports are fine.

Who it is for

Almost everyone. Families who want a 32L workhorse that reheats leftovers and defrosts chicken without fuss. Renters who want something reliable they can take to the next house. Anyone who does not need convection or air fry and does not want to pay for them. The ST665B is the default recommendation unless you have a specific reason to pay more.

Your rights under Australian Consumer Law: At $349 to $399, the NN-ST665B sits in the mid-range tier, and a reasonable consumer would expect 5 to 7 years of usable service from a microwave at that price. Panasonic's manufacturer warranty is only 1 year, which is notably less than the 2 years their predecessor NN-ST67JS carried. That makes the ACL backstop the more important one to lean on. If the magnetron fails at three years, if the door switch dies at two, if the control panel goes dark at four: all of those fall inside the reasonable-lifespan expectation, and all of them are consumer guarantee claims. Take it back to the retailer (Harvey Norman, The Good Guys, Appliances Online, Bing Lee, JB Hi-Fi, wherever the receipt says), explain the fault, and ask for repair, replacement or refund. The retailer is responsible under the ACL, not Panasonic. They can refer the matter to Panasonic service, but that is their problem, not yours.