Our standard operating temperatures are 86-122° Fahrenheit (30-50° Celsius). Rest assured, this is normal and will not affect the functionality of the device, nor damage any hardware. Our hub adapters are BUS-powered and include active chipsets that will power themselves once connected to your computer. Yes, the adapters will get warm when plugged into the computer, even with nothing plugged into the ports of the adapter.
Please feel free to contact us if you were to have any additional questions or concerns.