Wintered 11 smaller hives (most were late swarms) in the garage, screen the entrance off with #8 hardware cloth (top entrance hives-I say this because I think top entrances can let the heat escape easier from a screened hive). I covered the windows to block most on the light. Average temp in the garage were from 40-50 deg. It was open twice a day for wife's car.
I would bring them in when it was below 20 and put them out for more than one day that was 45+. Our winter has been up and down, so it was at least weekly I was moving them back and forth, got to be a real pain. Several are as small as 2 frames, and a few are 7 or 8 frames. There were a few days they got too warm that they were trying to chew through the screen while in the garage. But most of the time they were quiet.
Out of the 11 lost one, it was much small than I though one of those 17 deg nights finished it. (queen was there)
Over all they did very well and I am sure I would have lost more than half if they were left outside. Would do it again in the furture.
Some were low on stores, gave them sugar blocks and about 1/8 cup of syrup on inner cover once a week.
I would have liked to use a pvc pipe for an outside entrance so I could have left them in place.
All were going crazy collecting dried pollen sub from a 5 gal bucket (more bees that when they are robbing a hive) for about a week. Now the real stuff is coming in, they are not touching the sub.