Will it fit a standard 18-inch cabinet opening?

Yes. It is 18 inches wide, about 32.4 inches high and 21.7 inches deep, sized for an 18-inch built-under opening. Check your cabinet height and depth before ordering.

How many place settings does it hold?

Eight place settings. That suits one or two people; larger households will run it more often than a 24-inch machine.

Is 47 dB quiet enough for an open kitchen?

It is quiet enough for conversation and TV in most open-plan rooms, but full-size premium dishwashers often run in the low 40s or high 30s.

Does it need a rinse aid?

It works without one, but the electronic indicator reminds you when to refill, which helps with drying and spotting in hard-water areas.

Is it worth choosing over a 24-inch dishwasher?

Only if space forces the smaller size. A 24-inch model holds more and usually runs quieter for similar money, so pick this one for the fit and the Monogram finish.