It's not quite done, but the heating element will be a light bulb underneath the pump. There's a fan underneath that will pump the hot air up through the left side, through holes, and back down through holes in the pump shelf. I haven't hooked up the power yet, but it will run through a thermostat set to keep the box nice and toasty. I will put a door on the cabinet that lets the spouts of the pump protrude through, similar to Rick Maddy's setup.