I also had to find out first, because of the variable performance there is no fixed category regarding energy class/efficiency (Automatic, Eco and Turbo), so I interpret something like B - G, for example. As far as the battery is concerned, I can only rely on what I can find on the internet: Li-Ion with 3,200 mAh. In my opinion, the price-performance ratio is excellent when compared with similar suppliers from Dyson - two small things that bother me: the joint could be "more robust" and the hoover and the tubes as a whole could be a little longer... there are 10 - 15 cm missing which can be chalked up to the design because the container can get in the way, but that's peanuts.