How do you keep the enclosure at a safe temp?

[Neal]

I think it would work without covering the front window. Of course nobody knows until someone tries though.

It wouldn't, which is why I said that before the thread kicked off. When snakes are exposed to low temps, if they're a species that brumates, you're going stress the snake out. Even with never opening that cage, it's the ambient temperature that will still affect it. Giving a hotspot? sure, ambient temps, negative.