I have the same one. Bought it from Home Depot a year or so ago. Love the fact that it uses a regular decor plate. Not the one that only belongs on certain USB 120(volt) outlets.

I just did a test with my iPad Air 2 and iPhone 6 plus. The iPad was at 64% and 15 minutes later it was at 72%. The iPhone 6 Plus, as you may know can charge from a 2.1amp charger at a faster rate than from a 1.1amp. Was at 83% and ended at 93% after the 15 minutes. Both were plugged into the same USB 120(volt) outlet at the same time.

It does not feel warm to the touch. So the generated heat maybe inside or it keeps cooler than other 2.1amp chargers.

KOT