It’s one of the simplest, easiest and cheapest ways to drastically shrink your electricity bills, and your climate footprint: switch out your old incandescent lights for energy-efficient LED bulbs.

A big market shift toward LEDs has brought about an energy efficiency revolution in the United States and around the world. But in a new article, I explore how older incandescent bulbs live on, notably in lower-end retailers like dollar stores. That means some of the poorest households continue to miss out on a chance to benefit from the newer technology, experts say.

Lighting accounts for as much as a fifth of the average American household’s electricity bill, and lower-income households already spend a disproportionately large part of their income on utilities.

Behind the staying power of these older bulbs is an effort by major manufacturers to delay energy efficiency standards, allowing them to prolong profits from a dying industry.

Why it matters: The older bulbs are slowing America’s overall energy efficiency gains. About 30 percent of standard light bulbs sold in the country in 2020 were inefficient incandescent or halogen bulbs. (That figure excludes California, which phased out most inefficient light bulbs.) In the European Union, the older bulbs are barely sold at all.