According to the Edison Foundation, nearly 40% of U.S. households, about 46 million residences, are outfitted with a smart meter for monitoring and managing electricity use. Some of these meters operate under direct load control (DLC), which allows the utility to intermittently interrupt service to connected appliances — such as electric heaters, central air conditioning systems, water heaters, hot tubs, and clothes dryer heating elements — during periods of peak electricity demand. In return for their willingness to accept these short (typically no more than a few hours) power interruptions, customers receive a payment or a credit on their electric bill. Smart metering is a form of demand-side management, and is an important part of the evolving smart grid.
