Is there any way to keep ambient temps up without using heat lamps? Room temperature in my house is around 70 degrees, but some snakes like BPs shouldn't have the temp go below 75 degrees, and ideally should be mid 80s on the cool side (right?)

So when you use a larger tank (like a 30 gallon) and the UTH covers about 1/3 of the cage floor, how can you keep the ambient temps on the cool side from getting too cool?