Here are two pics.
The first show the difference between the insulated hive (white) and a regular hive (green).
The second show the thickness of the wall between the inner wall and outer wall. My hive top feeder is on which makes the picture not quite as good. It is chilly this morning and I didn't dare move it off as I didn't have my veil on.
After my great uncle passed away his 4 hives were left untended. There were 3 standard equipment hives and this one. This was the last one to die out and I believe that took several years to happen.