In Homes

What uses more energy in our homes — heating, cooling, lighting, or powering electronics like TVs, computers, and MP3 players? And, do houses in the United States use more electricity or natural gas?

In Homes Basics

The ability to heat and cool is one important accomplishment of modern technology. Our ovens, freezers, and homes can be kept at any temperature we choose, a luxury that wasn't possible 100 years ago. But keeping our homes comfortable uses a lot of energy.

Lighting is also essential to a modern society. Lights have revolutionized the way we live, work, and play. Most homes still use the traditional incandescent bulbs invented by Thomas Edison. These bulbs convert only about 10% of the electricity they use into light; the other 90% is converted into heat. In 1879, the average bulb produced only 14 lumens (a measure of the quantity of light) per watt, compared to about 17 lumens per watt from modern incandescent bulbs. By adding halogen gases, the efficiency can be increased to 20 lumens per watt.

Compact fluorescent bulbs, or "CFLs," have made inroads into home lighting systems in the last few years. These bulbs last much longer and use much less energy than incandescent bulbs, producing significant savings over the life of the bulb.

Appliances such as refrigerators, washing machines, and dryers are also more energy efficient than they used to be. Congress passed the National Appliance Energy Conservation Act in 1990 that requires new appliances to meet strict energy efficiency standards. Learn what it means to be energy efficient.

The amount of energy we use in our homes mainly depends on the climate where we live and the types and number of energy consuming devices we use. The pie chart on the right shows the major energy uses in homes in 2009, when most energy use was for space heating (42%), followed by electronics, lighting and other appliances (30%), water heating (18%), air conditioning (6%), and refrigeration (5%). (Watch a videoabout changes in home heating.)

The number and variety of ways we use energy in homes is changing rapidly. Energy use for air conditioning has doubled since 1980. U.S. households currently plug in more appliances and electronics at home than ever before. While refrigerators and cooking equipment have long been standard in homes, the ownership of appliances such as microwaves, dishwashers, and clothes washers and dryers has increased over the past 30 years.

It is increasingly common for homes to use multiple televisions and computers. Additionally, the home electronics market is constantly innovating, and new products such as DVRs, game systems, and rechargeable electronic devices are becoming ever more integral to our modern lifestyle. As a result of these changes, appliances and electronics (including refrigerators) now account for nearly one-third of all energy used in homes.

Types of Energy Used In Homes

Natural gas and electricity are the most-consumed energy sources in U.S. homes, followed by heating oil, and propane. Natural gas and heating oil (fuel oil) are used mainly for home/space heating. Space heating accounts for the largest share of the energy used in U.S. homes. Electricity, which is used for heating and cooling, also lights our homes and runs almost all of our appliances including refrigerators, toasters, and computers. Many homes in rural areas use propane for heating, while others use it to fuel their barbecue grills.

Regional Consumption Data Reflect Population Shifts and Climate

In the late 1990s, homes in the South Census Region surpassed the Midwest in consuming the most energy in the United States. This shift reflects the economic boom in the region, which stimulated U.S. migration to the South and the construction of more and larger homes. In 2009, homes in the South consumed 3.22 quadrillion Btu, about 3% of the country's total energy use and about 32% of energy used in homes.

Due to the longer heating seasons, the Northeast and Midwest regions still,
consume the most energy per household, at 108 and 112 Million Btu per
household in 2009, respectively.

Gains in Home Energy Efficiency Offset by More Electronics and Appliances

Total residential energy consumption has varied between 9.5 and 10.5 quadrillion Btu over the past 30 years. During the same period, U.S. population grew by 30% while the number of homes grew by about 40%. Energy consumption, however, grew at a slower rate, due to improvements in building insulation and efficiencies of heating and cooling equipment, water heaters, refrigerators, and other major appliances. However, these efficiency gains were offset by increases in the number of homes with cooling equipment, clothes washers and dryers, and dishwashers. Additionally, a growing number of U.S. households now have multiple televisions, computers, and refrigerators.

Use of Consumer Electronics Increasing

While most home appliances have become more efficient over the past 30 years, the average U.S. household uses many more consumer electronics — in particular, personal computers, televisions and related devices.

In 1978, personal computers were expensive and not typically used by U.S. households. In 2009, 76% of U.S. homes had at least one computer, 8% more than just four years prior, and 35% had multiple computers. Also, most households had only one television in 1978. In 2009, the average household had 2.5 televisions. Over 45% of homes have at least one television with a screen size of 37 inches or larger. Screen size and average energy consumption per television have continued to grow over time.

DVD players and Digital Video Recorders (DVR), which did not exist 15 years ago, are now widespread. As of 2009, 79% of homes had a DVD player, and 43% had a DVR. Nearly a third of all households also had at least four electronic devices, such as cell phones, plugged in and charging at home.

Air-Conditioning Equipment Becomes Increasingly Common

The percentage of homes with central air-conditioning has more than doubled since 1980, with more than 60% of homes having a central system. All areas of the United States show a significant increase in air-conditioning equipment and use in recent years. Cooling accounted for about 6% of total residential end use energy consumption in the United States in 2009, double its 1980 share. Except in the temperate climate regions along the West coast, air conditioners (AC) are now standard equipment in about 87% of U.S. homes.

Energy Use in Different Types of Homes

About 80% of residential energy use is consumed in single-family homes, while 15% is consumed in apartments and 5% is consumed in mobile homes. These different home types, along with variation in home size, structure, climate, and vintage, contribute to the diversity in energy use in homes across the United States.

Single-Family Homes:

More than half of single-family homes use natural gas for space heating, while about one-quarter use electricity. Most single-family homes use three or more televisions and almost all single-family homes use a clothes washer and dryer.

In 2009, for main space heating equipment:

• 54% used natural gas
• 28% used electricity
• 6% used fuel oil
• 6% used propane/LPG
• Some houses don't use heat at all

For appliances and electronics:

• 96% used a clothes washer
• 94% used a clothes dryer
• 81% used a computer
• 67% used a dishwasher
• 53% used three or more televisions

Apartments

Natural gas and electricity are used for space heating in about the same number of apartments. About three-quarters of apartments use air conditioning equipment and more than one-third contain clothes washers and dryers.

In 2009, for main space heating equipment:

• 43% used electricity
• 42% used natural gas
• 6% used fuel oil
• Almost none used propane/LPG

Mobile Homes

Mobile homes are the most likely type of home to heat with propane/LPG. More than one-half of mobile homes use electricity and about one-fifth use natural gas for space heating. Unlike apartments, most mobile homes contain clothes washers and dryers.

In 2009, for main space heating equipment:

• 57% used electricity
• 20% used natural gas
• 12% used propane/LPG

Eighty-four percent of mobile homes have air conditioning (central system, wall/window units, or both).

For appliances and electronics:

• 90% used a clothes washer
• 83% used a clothes dryer
• 52% used a personal computer
• 36% used three or more televisions
• 33% used a dishwasher