In the last year, about 20% of Americans struggled to pay their energy bill in full at least once, according to a study by Help Advisor. At the same time, 18% kept their house at a temperature that was either unhealthy or unsafe.

Even more people went without necessities to make sure they could afford their utilities. More than 28% skipped a basic expense such as food or medicine to pay an energy bill in the last 12 months, according to the study.

"It's absolutely startling," said Christian Worstell, a senior writer at Help Advisor, adding that the most vulnerable households tend to be those with children under 18, people of color and folks who have the lowest incomes.

"It does appear the problem has been accelerating slightly, but this is nothing new," he said.

Increasing costs

Nearly half of U.S. households that heat with natural gas are projected to spend 30% more than they did last winter on average, according to the Winter Fuels Outlook 2021 report from the U.S. Energy Information Administration. The 41% that heat with electricity are expected to spend 6% more.

The smaller number that heat with propane or heating oil — 5% and 4% of households, respectively — could see even bigger leaps in cost. Propane users will spend 54% more this winter, while heating oil users could see bills go up 43%, according to the report.