We're insulating mostly from the winter cold. We typically get -20 in the winter... Summers sometimes reach 98 where this shed is located, but it'll be shaded. I'm both an electrician and an HVAC designer/installer. If we have to add air conditioning, we will, but I'm hoping ventilation will be the most I need. If not, we'll get a little portable a/c unit. For heat, we'll have to use electric heat, as heat pumps aren't feasible down to our low temps.