It’s been stated many times that electricity is the backbone of every strong economy. We have certainly witnessed this in the U.S., as the development of our unparalleled electric system has mirrored our rise to leader of the world economy. Since the beginning of electrification in the U.S., household consumption has been on the rise. Data published by the Energy Information Administration (EIA) indicates that average U.S. household electricity consumption increased at an average rate of 1.4 percent per year from 1970 through 2007. Growth moderated over the last 10 years of that period, averaging 1.1 percent per year. Recent trends and events are impacting a much slower growth in household consumption, and many utilities are now projecting a continued leveling of household consumption over the long term. The EIA currently projects average household consumption growth to slow to less than one percent per year in both 2009 and 2010. This article examines the underlying influences on household electricity consumption, past and present, and considers how consumption will change in future years.
Current Consumption Levels
Average U.S. household electric consumption in 2005 was 11,480 kWh. The average is by far highest in the South as the market shares for electric space heating, air conditioning, and electric water heating exceed those for all other regions. Note the proportions of end-use consumption presented in the graph represent entire regions and will vary significantly across individual utilities depending on end-use market share.
Growth Factors
Central Electric Heating and Cooling - An increase in the number of homes built with central HVAC systems was a primary reason for high increases in average household consumption from the 1960s through the 1990s. At the national level, the percentage of homes with central air conditioning nearly tripled from 1978 to 2005, increasing from 23 to 65 percent. Similarly, the percentage of homes with central electric heating increased from 16 to 43 over the same period. In many areas of the country, the market shares for central electric heating and cooling systems continue to increase, but they are doing so at slower rates as they approach maximum saturation levels.
Other Appliances – In addition to electric heating and cooling, increases in the ownership and use of electric water heaters, electric kitchen appliances, and various electronic devices have contributed to the rise in household energy use. Particularly in recent years, we have witnessed tremendous growth the use of wide screen televisions (plasma and LCD), not to mention increases in the number of televisions in the home. In addition, the market shares for personal computers, gaming devices, cell phones and other miscellaneous “plug loads” continue to skyrocket, all of which increase electric consumption. When left in idle mode, and even when turned off, these plug loads continue to draw load. For example, a PlayStation 3 game console consumes up to 180 watts during idle mode . That equates to over 1,500 kWh during the course of a year. This is significant, as the National Resources Defense Council estimates that 50 percent of users do not turn off their machines when not actively playing.
Home Size – The “American Dream” for many, if not most, includes owning their own home. Apparently, when it comes to homes, bigger is better. The average home size in the U.S. increased from 1,630 sq. ft. in 1993 to 1,826 sq. ft. in 2007. The amount of energy required to comfortably heat and cool a home increases as the size of the home increases. In addition, the number of televisions, computers, telephones and other electronic devices tend to increase with home size.
Economic Prosperity – During periods of economic prosperity, many consumers get a case of the “let the good times roll” attitude. Householders upgrade to larger homes. Up pop swimming pools and hot tubs. Air conditioners and heating systems may run longer as consumers are willing to spend for a little more for comfort. In short, increases in disposable income typically translate into higher levels of energy consumption.
Factors Limiting Growth in Household Consumption
Declining People per Household – The average number of people per household in the U.S. has been declining since before 1969, falling from 3.2 in 1969 to an estimated 2.6 in 2007. While household consumption increased over the same period, growth would have been higher had average household size not been on the decline. The decline in household size has slowed considerably, and current projections indicate a leveling before reversing to a slight increasing trend around 2020. (Author’s note – As anecdotal evidence, my household size fell from 3 to 2 in 2007, and average consumption dropped 15-20 percent. I no longer have to say “Close the door”, “Turn off the lights and television”, and “No more 20-minute showers!”).
Vintaging of Major Appliances –Major appliances break down and must be replaced periodically. The vintaging of major appliances, or “out with the old and in with the new”, significantly impacts total household consumption. The enactment of federal appliance standards has resulted in the replacement of older inefficient HVAC systems with new higher efficiency systems. Central heating and cooling systems installed today use approximately 20-30 percent less energy than units installed 15 years prior. Expect the vintaging of major appliances to continue impacting average household consumption until all the “clunkers” have been replaced with models that meet existing standards. Utility planners must take care to address the vintaging of major appliances in their forecasting process.
Compact Fluorescent Lighting – Sales of compact fluorescent lighting (CFL) are booming, and there appears to be no slowing over the near term. EIA reports that 200 million CFL bulbs were sold in 2007. One 13 watt CFL produces about the same output as one 60 watt incandescent bulb. Energy Star qualified CFLs use approximately 75 percent less energy than a standard incandescent bulb and last nearly 10 times longer. EIA reports that lighting represented nearly 16 percent of household consumption in 2007. The Energy Independence Security Act of 2007 mandates wattage on general-service incandescent light bulbs be reduced by about 28 percent by 2014, and then to 65 percent by 2020.
Energy Efficiency and Conservation – With the rise in costs for building and operating new electric generation facilities, electric utilities are implementing energy efficiency and conservation programs to minimize increases in consumption and to help defer the need for new generation facilities. Compact fluorescent lighting, Energy Star appliances, and insulation and weatherization programs are examples of cost effective measures directed towards residential customers.
Economic Recession – This year, analysts predict the economy will shrink anywhere from 2.0 to 2.5 percent, the worst performance since 1946. In addition to a slumping economy, electricity prices are generally increasing across the country. EIA reports that residential prices at the national level will increase approximately 2.3 percent in 2009 and 2.0 percent in 2010. There is no guarantee average U.S. household consumption will decline in 2009, but it is certainly possible that consumers will limit electricity use when possible in light of the economic recession and rising prices.
Information provided by John Hutts, GDS Associates, Inc., Marietta, GA.
Copyright 2010 South Alabama Electric, P.O. Box 449, Troy AL 36081, 334.566.2060
household consumption growth to slow to less than one percent per year in both 2009 and 2010. This article examines the underlying influences on household electricity consumption, past and present, and considers how consumption will change in future years.
but they are doing so at slower rates as they approach maximum saturation levels. 
Declining People per Household – The average number of people per household in the U.S. has been declining since before 1969, falling from 3.2 in 1969 to an estimated 2.6 in 2007. While household consumption increased over the same period, growth would have been higher had average household size not been on the decline. The decline in household size has slowed considerably, and current projections indicate a leveling before reversing to a slight increasing trend around 2020. (Author’s note – As anecdotal evidence, my household size fell from 3 to 2 in 2007, and average consumption dropped 15-20 percent. I no longer have to say “Close the door”, “Turn off the lights and television”, and “No more 20-minute showers!”). 
Compact Fluorescent Lighting – Sales of compact fluorescent lighting (CFL) are booming, and there appears to be no slowing over the near term. EIA reports that 200 million CFL bulbs were sold in 2007. One 13 watt CFL produces about the same output as one 60 watt incandescent bulb. Energy Star qualified CFLs use approximately 75 percent less energy than a standard incandescent bulb and last nearly 10 times longer. EIA reports that lighting represented nearly 16 percent of household consumption in 2007. The Energy Independence Security Act of 2007 mandates wattage on general-service incandescent light bulbs be reduced by about 28 percent by 2014, and then to 65 percent by 2020. 