My room is ideal temperature...for the warm half.

the ambient temp in my room is already mid 80's, so with the heat mat on, + humidity, it's going to be bloody hot on the "hot" side of my viv, will this be an issue?

actually I was thinking about this too, because the summer here is excruciating... obviously you wont need the heat mat on , but how do u make the viv colder? Although I read in a previous post that they like soaking if the feel hot.

If the heat is off, that would eliminate any temp gradient. which...is bad.

not necessarily. our entire reptile room at the zoo is a constant 83 degrees. For most of our animals there, that's fine and we just have heat lamps for the ones that need a little extra, but that's not very many (and they're mostly lizards that need it). My heat mat has been off for about 3 months and my snake is doing fine. As far as making a viv colder, I know that one of the things we do with our geckos at work is put an ice bottle in the enclosure with them. BUT I don't know if that's a good idea with snakes because the geckos never actually touch the ice, whereas a snake probably would. I'm interested to hear other people's ideas on this.

in the summer i turn off the heat pads, and have a fan blowing on low on my cages, and brings the temps to 79 degrees

I have most of my corns in heated racks, but I have a small room I incubate eggs in. I also keep several adult corns in that room . It is always between 80 and 85 degrees. I have kept snakes in there for years without problem.

You do not need a temperature gradient.