I don't know if you "could" plug the heater directly into the EB8, but most people plug in the controller into the EB8 and set the heater's controller a degree or two higher than the Apex control setting as a shut off fail safe. In other words, set the Apex at 78 and the heater controller at 79 or 80. If the EB8 fails, the controller should shut off the heater.