Annie Dudley, a statistician from Chapel Hill, N.C., slashed her energy consumption a few years ago. She installed a geothermal system, which uses the earth’s steady temperature to help heat and cool her home, replacing an aging system that came with the house. She later added 35 solar panels on her roof and two Tesla home batteries, which can provide enough power to meet most of her needs, including charging an electric Volkswagen Golf.

“The neighborhood has lost power a whole lot, but I have not,” Ms. Dudley said.

She spent about $52,000 on her solar panels and batteries, but $21,600 of that cost was defrayed by rebates and tax credits. Ms. Dudley estimates that her utility bills are about $2,300 a year lower because of that investment and her geothermal system.

Generator companies believe that growing electricity usage and the threat of outages will keep demand high for their products.

Last year, Generac had $2.8 billion in sales to U.S. homeowners, 250 percent more than in 2017. In recent years, many people bought generators to ensure outages would not interrupt their ability to work from home, said Aaron Jagdfeld, the chief executive of Generac, which is based in Waukesha, Wis. Many people also bought generators because of severe weather, including an extreme heat wave in 2021 in the Pacific Northwest, and winter storm Uri, which caused days of blackouts in Texas and killed an estimated 246 people.

“People are thinking about this,” Mr. Jagdfeld said, “in the context of the broader changes in climate and how that may be impacting not only the reliability of power but the things that they need that power provides.”