This article is from the Food Preserving FAQ, by Eric Decker firstname.lastname@example.org with numerous contributions by others.
Dehydrator Features to Look For
Double wall construction of metal or high grade plastic. Wood is not
recommended, because it is a fire hazard and is difficult to clean.
Enclosed heating elements.
Counter top design.
An enclosed thermostat from 85°F to 160°F.
Fan or blower.
Four to 10 open mesh trays made of sturdy lightweight plastic for
UL seal of approval.
A dial for regulating temperature.
A timer. Often the completed drying time may occur during the night and a
timer could turn the dehydrator off and prevent scorching.