I also live in the northern states, but I can use closets and what ever room I wish.. You're idea seems possible, just have to keep checking on the fans time to time to make sure they are running well, and make sure to have a measuring device for temp. and humidity, if your pulling semi-warm air in it should be fine, might want to get some perlite, just a suggestion. I've known some that have grown during the winter in the northern areas in the basement with no heat cept the growbox and perlite, and they where still very healthy plants.
Hope that helps you some, any more questions of my post just let me know, laters
