When shopping for a garbage disposal, you’ll find models filed under two categories: continuous feed and batch feed.
Continuous-feed disposals are far more popular and the type you’ll see in most homes. You flip a switch to whirr it into motion and (with cold water running) toss in food scraps as it grinds. Often, that switch is wired into the wall above the sink.
“But in old homes, getting that switch on the wall and rewiring the electricity can be very difficult and expensive,” says Mark Cammarota, vice president of marketing for InSinkErator, the brand that invented the garbage disposal in the late 1920s. “The batch-feed model came out in the early '60s as a solution. The switch is actually built into the cover that you place over the disposal.”