I'm in North Idaho... very cold here it seems. We did insulate our coops and have 2 windows in each one and vents as well. I like the insulation but it was free for us... left overs from my husbands construction jobs. I wouldn't go any other way but insulation in climates that get below 0 F degrees. Just my oppinion... some people in Alaska don't insulate and it seems to work for them.