It's 7.5W with the both input signal disconnected, on a minimum volume, or even on the first ~10% of a volume. It's sad that this speaker don't have some sort of autosleep, because with the price of 0.4 eur per kw/h and leaving the E3.5 idle for 20 hours a day, it's a wasted 20 euros a year, that could be spend in a better audio system...