Cap Heat - (in MN or other cold winter states)

[Todd M.]

I have 4 plex in which I pay heat. gas. The 4 units have digital thermostats that are capped to 72F.

Is this legal? Does anyone know what the minimum cap is? especially in Minnesota? I'm searching online and can't find any reference.

To be clear of my intentions: I'm not interested in setting it to the absolute lowest... rather I hope to say something like: "legally I can cap it at 68 degrees, but since I'm such a nice guy, i'm capping it at 72. if you'd like the cap adjusted higher than 72, it's an extra $25/month per additional degree in temperature"

Thoughts?