This is always a hard question to answer. If you limit ventilation and insulate the aquarium, then yes, you likely could. I use only heat mats in my glass quarantine tanks, but my herp room currently sits at about 78-80 ambient temps. Everyone's situation is different. Best way to figure out if you can do this is to just set it up and take temps. If you can get an ambient temp in the mid to high 70s, and close to a 90 deg hot spot then you should be fine. You can always go to a packaging store and get some thin sheets of Styrofoam to insulate the sides, and then foil the top or lay a piece of fiberglass or melamine on the top.