bringing containers in for winter

I want to bring some herbs in for the winter, not to use in cooking so much, but so that they can survive the winter. Some of them are borderline hardy in my zone (5-6 ) and do not always survive the winter, such as sage and rosemary. I have a southern exposure, unheated sunporch that gets full unobstructed sun all day. It does get very cold in this room. but not below freezing. Will not keeping these herbs in this room be the same as keeping them outside, simulating winter in a slightly higher zone and thereby providing conditions for survival?