I use poly hives all winter. Here in SE Michigan, I don't use top entrances in my condensing hives, the bees get all the water from the sides of the supers. I've actually pulled a colony apart in Mid February out of curiosity a while ago during a warm snap & saw water on the walls of the super but the cluster was dry as can be. I assumed that they were collecting water from the sides of the hive. From what I can tell, when you put bees in an insulated hive for the winter & only use a bottom entrance, more heat is retained in the colony & the bees don't eat very much over winter. With wooden hives, I had to put 2 medium supers full of honey in order for them to get thru the winter. With poly hives, my colonies only consume about 30-40 lbs from October thru April.