<p>The electrical power of a vacuum unit (17) can be reduced depending on the operating state of the roller brush (28). The power may be reduced by the electrical power rating of the drive motor (29) of the roller brush. The power reduction may be at least 20 per cent. The vacuum cleaner may have a mains connection (34), and be selectively operated by the mains connection or the rechargeable battery (31).</p>
