Well obviously a person wouldn't put a snake tub/tank in a freezing cold room, hoping that just because you have a herpstat on it, all temps will be perfect. I have 2 herpstats, 1 on a rack system and the other on a PVC tank with plexiglass front window. They are both totally different setups altogether, yet after you get them dialed in, you can guarantee your temps will stay within 1-2 degrees at all times.
Like I was saying earlier, I had a Zilla1000 tstat running my tubs, which are exact same setups, in a heated room on a thermostat, and temps bounced around all day, sometimes getting just under 100f.