That's exactly what I'm doing, an STC-1000 controlling an old fridge in my garage, with the heating side plugged into a 100w floodlight that sits in the bottom of the fridge. Works perfectly for any kind of brew, any time of the year.
Just bought another STC-1000 to use in a cupboard in my garage to keep it above 18C so I can bottle condition my ales out there (currently doing that inside). At $18 delivered, plus a few dollars for the wiring/plugs, they're great value. Got my latest one from here:
http://www.ebay.com.au/itm/220V-Digital ... b02&_uhb=1