I just un-plugged my father's oxygen concentrator from the Kill-O-Watt. 4.42 kwh for a 12 hour period. The thing runs 24/7 so 8.82 for a 24 hour period. So far in searching the internet for specifications I have found that manufacturers don't advertise much in the way of power requirements. Hoping someone on the forum may have already researched this topic, and could provide some guidance.