Electricity revolutionized appliances in another way, powering small motors that could perform work formerly done by muscles. The first such household device, appearing in 1891, was a rotary fan made by the Westinghouse Electric and Manufacturing Company; its blades were driven by a motor developed chiefly by Nikola Tesla, a Serbian genius who pioneered the use of alternating current. The second was a vacuum cleaner, patented by a British civil engineer named H. Cecil Booth in 1901. He hit on his idea after observing railroad seats being cleaned by a device that blew compressed air at the fabric to force out dust. Sucking at the fabric would be better, he decided, and he designed a motor-driven reciprocating pump to do the job. Soon the power of the electric motor was applied to washing machines, sewing machines, refrigerators, dishwashers, can openers, coffee grinders, egg beaters, hair dryers, knife sharpeners, and many other devices.

At the turn of the century, only about one American family in 15 employed servants, but having such a source of muscle power was devoutly craved by many and was seen as a key indicator of status. As housework was eased by electric motors and the number of servants dropped, such views changed, but some advertising copywriters insisted on describing appliances in social terms: "Electric servants can be depended on—to do the muscle part of the washing, ironing, cleaning and sewing," said a General Electric advertisement in 1917; "Don't go to the Employment Bureau. Go to your Lighting Company or leading Electric Shop to solve your servant problem."

The electric servant brigade was rapidly improved. In 1907 an American inventor named James Murray Spangler created a vacuum cleaner that basically consisted of an old-fashioned carpet sweeper to raise dust and a vertical shaft electric motor to power a fan and blow the dust into an external bag. Manufactured by the Hoover Company, which bought the patent in 1908, it was hugely successful, especially after Hoover in 1926 extended the fan motor's power to a rotating brush that "beats as it sweeps as it cleans." Meanwhile, the Electrolux company in Sweden grabbed a sizable share of the market with a very different design for a vacuum cleaner—a small rolling cylinder that had a long hose and a variety of nozzles to clean furniture and curtains as well as carpets.