New Crestie, advice please

We bought a Crestie today, after doing a little research on the web.

He came in a 45wx45dx60h exo terra. The set up is fantastic, lots of hiding places and things to climb.
It has a light canopy on top.
My question though is regarding the heat mat. Theres a 12"x6" heat mat on the inside of the tank, behind the polystyrene backdrop. I don't feel any heat against the backdrop, but there is plenty of heat if i touch the outside back of viv.

I'm feeling we may need the heat mat during colder months during the night at temps drop, but surely the backdrop is acting as an insulator and preventing the heat getting into the viv?

Thoughts please?

Heat mat is useless in my opinion for a crestie. A ceramic heater is ,uch more effective, helps create a thermal gradient. Heat mat is much better for a leopard gecko as they absorb heat differently. Try blu tacking the heat mat to the outside of the viv near the top. what sort of temps do you have in the viv?