Kudos for setting up the enclosure prior to getting your bp. Can you imagine how much more stressed you'd be if you had a young bp in there?
I'm not surprised you're having trouble maintaining your temperatures. How's your humidity? Glass enclosures with screen tops don't hold heat or humidity well. You can insulate the sides. Try foam posterboard and, definitely, get a UTH. I like heat tape.
All your heat sources need to be regulated with a thermostat. If the temp jumps when you're not around, it can be disastrous for your snake. I use Jumpstarts on my enclosure.
Post a pic of your set up and we may have more suggestions for you. This thread will show you how to post them: https://ball-pythons.net/forums/show...-Post-Pictures.
Frankly, though, you'd be better off getting a pvc enclosure and outfitting it with a radiant heat panel and heat tape. It's expensive, but it should work, even in a cool home like yours. It'll look a lot better too.