Unless it dips below 14 deg you don't need to use it, that's what the internal switch on it is set for. either 0 deg or 14 deg.After reading a few past threads about block heaters and the codes that can be thrown when the temps are not cold enough for the ECU programming, I am debating about installing the OEM block heater and just getting one of those adhesive squares to heat up the oil pan when it gets really cold out here.
There is a convenient electrical outlet on an outside wall right near the driveway so I can plug in whatever I decide to use.