Well, we have been living in the 'Tin Can' for about 2 yrs now. Summers definitely require an air conditioner so I am so glad we have put one in, 18,000 BTU Window air conditioner. Though we cut a space into the container as we know we'll always require one due to the heat. The back part of the house tends to remain at around 72 degrees, but the front gets warmer as the sun hits it most of the morning. Temps here can go into the 100s & it just wouldn't be bearable in the front of the house without A/C. Winters are a bit milder, though this last one has given us some lower temps, w/wind chills into the minus areas. The only heat we have is a wood stove & that seems to work well. The back part stays around 64 degrees in the winter. I do use a small electric heater in the bathroom area as it stays cooler being as it's in the back part of the house & in winter I don't really enjoy stepping out of the shower in a room that's around 64 degrees.
In the time since I last posted, we have added more insulation to the roof, blow in type, which seems to have helped with controlling the temperatures. We've also finished the screened room which we use a lot during the spring & fall.
All in All we love this place, though I do find I have less space than I thought I would, but it could just be that I gather too much junk.