According to the review quoted below, they draw 180 watts at idle.
Times 2 is 360 watts. So about 60 watts more then a pair of BHK 300s at idle.
“With 60 watts of Class A power, that means 180 watts of power are dissipated as heat when the amp is idle. Leaving the XPA-1in Class A mode at idle for an hour bears this out, as the amps will become quite warm.”