Tracing the history of heating fuels from 1940 to 2000 shows that 3-in-4 households used coal or wood in 1940, whereas only 1.8 percent of homes used these fuels in 2000.

Homes using coal or coke for heating fuel dropped rapidly in each decade between 1940 (55 percent) and 1970 (2.9 percent); and the rate continued to drop until 0.1 percent of homes used these fuels in 2000.

Wood, used as a major heating fuel in 1940 (23 percent), virtually disappeared by 1970 (only 1.3 percent). Since that time, it has shown a modest comeback in 1990 (3.9 percent), but dropped in 2000 (1.7 percent). It was the dominant fuel in the Pacific Northwest and South in 1940.

In 1940 electricity as a heating fuel was so rare that its use was not counted at all by the Census Bureau. Even by 1960, electricity was only used by 1.8 percent of the country. After that year, electricity usage began to climb rapidly each decade, reaching over one-quarter of American homes by 1990 and heating 30 percent of homes by 2000. (See graph)

Utility gas (including bottled gas) was used by 11 percent of homes in 1940, although it was dominant in California (67 percent). Its growth was very rapid, rising to over 50 percent by 1970 and leveling off.

In 2000, 82 percent of homes used either utility gas or electricity as their primary source of heating fuel; utility gas alone accounted for about half of all homes (51 percent). Utility gas was clearly the dominant fuel in Utah, Illinois, Michigan, Colorado, and Kansas.

The percent of homes using fuel oil (including kerosene and other liquid fuels) has fluctuated from 1940 to 2000. That rate has increased each decade from 1940 (10 percent) to 1960 (32 percent). From that point, it declined each decade, to its lowest level of 9.0 percent in 2000. Fuel oil was tops in New England; for example in 2000, 80 percent of the homes in Maine used fuel oil, followed by Vermont (59 percent), New Hampshire (58 percent), and Connecticut (52 percent).