Careful what you wish for... For about a year I lived about 2 miles from work, long enough I didn't wan't to necessarily walk everyday, but really more of a nuisance to ride.
Personal factors such as sweating, hills, etc factor in... But for two miles I still needed to wear different clothes, get my bike out and then just about the time I was warm in the winter or sweating in the summer I was at work.
Ride longer you say, I just never made it happen.

Current route is a tad over 7 and most mornings I wish it was a bit longer. Keep riding, or go into work.