Jonathan Robidoux, a Long Island resident, calls his heating oil supplier every fall to have his tank filled for the coming winter. He spent $1,200 on the fuel last winter.

This year, he will likely pay a lot more.

The price of heating oil, a fuel that is very similar to the diesel used in trucks, is up roughly 60 percent since Israel and the United States started attacking Iran on Feb. 28.

The war has sent oil and fuel prices soaring, leaving Mr. Robidoux and many others facing difficult financial decisions. About 3 percent of U.S. households use heating oil, and most of them live in the Northeast or Alaska.

Mr. Robidoux, who rents a home in New Hyde Park, N.Y., is trying to decide if he should buy heating oil now or wait until the weather gets colder, in the hope that prices will drop.

“I might just buy some now, but I don’t have that much liquidity, so it’s a tough decision,” said Mr. Robidoux, 41.

People who use natural gas or electricity to heat their homes are expected to face more modest increases in heating bills but many of them could also find it hard to make ends meet, energy experts said.

Many Americans are heading into a “much more expensive” winter, said Mark Wolfe, executive director of the National Energy Assistance Directors Association, which represents state officials that help dispense government aid to residents who meet certain income-based qualifications. The organization urged Congress in July to offer more financial assistance to families struggling with rising energy costs.

“Those numbers, if you’re middle class, that’s a significant hit to your budget,” he said.

Who will face higher costs and why?

As with gasoline and diesel, heating oil prices can vary a lot based on where you live. The national average, which was $4.10 a gallon the week before the war, jumped 35 percent to $5.54 just a month later, according to weekly data from the Energy Information Administration, which will begin releasing weekly price data for heating oil in the fall.

In New York, the average price of heating oil was $6.14 a gallon the week of Sept. 14, up from $3.70 a year earlier, according to the state’s Energy Research and Development Authority.

More than 80 percent of U.S. heating oil is used in the Northeast. In the winter of 2023 to 2024, 4.79 million households used oil as their primary heating fuel, according to the E.I.A.