>running the a/c ... i know. seems really stupid in january...

Cranking up yer AC is an extremely useful adjunct to the defroster for
keeping your windows fog free (a chronic winter condition up here,
especially when hiking, fishing, etc. and you climb in your rig with
soaking wet gear). 

Turn both on full blast and set your vents to recirculate. The defrost
heats the windows while the AC dehumidifies and you're fog free in no time.

Paul