Greetings BEE-Lers, I. Watson brought up the subject of ventilation vs condensation. Here's my 2 cents: In a wet pacific coastal environment it gets cold but there's few serious frosts and no snow. Masonite covers such as inner covers and tele covers invite major condensation problems. I like to use an inner cover with window screen stapled over the hole for ventilation year around. In the cold season I cover that with 3/4" to 1" thick styrofoam and make a thumb sized hole over the screen. Add some spacers and a big plywood raintop and my bees stay warm and dry. I've seen all kinds of ventilation doodads. Experiment and use what works. Good Luk. H.Sweet