i've had experience with Carrier and now with Tri Pac. The carrier had more functions on the control panel, and you could use it to "limp" if the truck alternator quite. The Tri Pac has less control, can't be run while engine is on ( no limp). However, the carrier was a lot louder than the tri pac. Also, tri pac uses espar heater as opposed to the electric with carrier. I love the espar, it will heat my house, and it's silent.