According to the latest report from the U.S. Energy Information Administration (EIA), released the last week of July, absolute and per capita residential energy usage continues to decline. The EIA reported that annual residential electrical sales declined 3 percent since 2010, residential electricity sales per capita declined 7 percent since 2010, and residential electricity sales per household declined 9 percent since 2010.

At the state level, residential electricity sales in 2016 ranged from a high of 6,619 kilowatt-hours (kWh) per person in Alabama, to 1,828 kWh per person in Hawaii.

Part of the reason for the declines relate to weather. The report noted that warm weather increases electricity demand as houses use air conditioners, fans, dehumidifiers, and other equipment to maintain comfortable temperatures. The extent to which cold weather influences residential electricity demand depends on heating fuel choices, with many homes using some form of electric heating in winter months.

The report noted that some of the states with the largest percentage decline in per capita residential electricity sales were also those with the largest changes in winter weather (milder winters) during the last seven years. Some of these states, mostly in the South, saw double-digit percentage declines in per capita residential electricity sales.

"Although changes in the weather are a key driver of year-over-year-fluctuations, energy efficiency improvements and economic factors have contributed to the decline in per capita residential electricity sales since 2010," the report states.

Investments in energy efficiency, many of which have been triggered by incentives provided by utilities and other energy service providers, have contributed to longer-term declines in residential electricity use.

In addition, more stringent energy efficiency standards for household equipment, such as heat pumps, air conditioners and lighting, are also reducing residential electricity usage, especially as older equipment is replaced by newer, more energy-efficient equipment. This includes the huge shift from incandescent lamps to compact fluorescents and, more recently, LEDs. In 2009, for example, 58 percent of all households reporting having at least one energy-efficient lamp. By 2016, that had climbed to 86 percent, and 18 percent of households reported having no incandescent lamps at all in their homes.

Finally, the growing popularity of small-scale home rooftop solar photovoltaic systems are contributing to the decline of retail electricity sales.