  We present a method to reliably select variable white dwarfs from large area
time domain surveys and apply this method in a pilot study to search for
pulsating white dwarfs in the Sloan Digital Sky Survey Stripe 82. From a sample
400 high-confidence white dwarf candidates, we identify 24 which show
significant variability in their multi-epoch Stripe 82 data. Using colours, we
further selected a sample of pulsating white dwarf (ZZ Ceti) candidates and
obtained high cadence follow up for six targets. We confirm five of our
candidates as cool ZZ Cetis, three of which are new discoveries. Among our 24
candidates we also identify: one eclipsing binary, two magnetic white dwarfs
and one pulsating PG1159 star. Finally we discuss the possible causes for the
variability detected in the remaining targets. Even with sparse multi-epoch
data over the limited area of Stripe 82, we demonstrate that our selection
method can successfully identify various types of variable white dwarfs and
efficiently select high-confidence ZZ Ceti candidates.
