This story originally appeared on Mother Jones and is part of the Climate Desk collaboration.

As President Donald Trump sees it, environmental regulations that attempt to improve efficiency and address climate change only make products more expensive and perform worse. He has long blamed efficiency regulations for his frustrations with things like toilets and showerheads. He began his second term in office to “unleash prosperity through deregulation.”

But there’s at least one big way that American companies and households may end up paying more, not less, for the president’s anti-environment policy moves.

If you’re in the market for a vehicle, you’ve probably noticed: Cars are getting more expensive. Kelley Blue Book reported that the average sticker price for a new car topped $50,000 for the first time in September.

And they aren’t just getting more expensive to buy; cars are getting more expensive to own. For most Americans, gasoline is their single-largest energy expenditure, around $2,930 per household each year on average.

While a more efficient dishwasher, light bulb, or faucet may have a higher sticker price up front—especially as manufacturers adjust to new rules—cars, appliances, solar panels, and electronics can more than pay for themselves with lower operating costs over their lifetimes. And Trump’s agenda of suddenly rolling back efficiency rules has simultaneously made it harder for many industries to do business while raising costs for ordinary Americans.

No one knows this better than the US auto industry, which has whiplashed between competing environmental regulations for over a decade.

President Barack Obama tightened vehicle efficiency and pollution standards. In his first term, Trump loosened them. President Joe Biden reinstated and strengthened them. Now Trump is reversing course again—leaving the $1.6 trillion US auto industry unsure what turn to take next.

Regulation Whiplash

In July, the Environmental Protection Agency began undoing a foundational legal basis that lets the agency limit climate pollution from cars. Without it, the EPA has far less power to require automakers to manufacture cleaner vehicles, which hampers efforts to reduce one of the single biggest sources of carbon emissions.

Trump’s transportation secretary, Sean P. Duffy, said in a statement over the summer that these moves “will lower vehicle costs and ensure the American people can purchase the cars they want.”

But in reality, the shift may have the opposite effect. That’s because when the rules change every few years, automakers struggle to meet existing benchmarks and can’t plan ahead. The Alliance for Automotive Innovation, a trade group representing companies like Ford, Toyota, and Volkswagen, sent a letter to the EPA in September saying that the administration’s moves and the repeal of incentives for electric cars mean that the current car pollution rules established under Biden and stretching out to 2027 “are simply not achievable.” The Trump administration responded by zeroing out any penalties for violations—but the industry is already planning for a post-Trump world where rules could drastically change yet again.

Because it takes years and billions of dollars to develop new cars that comply with stricter rules, carmakers would prefer if regulations stayed put one way or the other. Every rule change adds time and expense to the development lifecycle, which ultimately gets baked into a car’s price tag.

Changing rules are also vexing for electric car makers, whose models are gaining traction both in the US and around the world, even as the Trump administration has ended tax incentives for EVs. Trump is making things even more difficult by pulling support for domestic battery production that would help US car companies build electric cars.

It all adds up to a huge headache for the industry. “Particularly in the last six months, I think ‘chaos’ is a good word because they’re getting hit from every angle,” said David Cooke, senior associate director at the Center for Automotive Research at Ohio State University.

And all that uncertainty is making cars more expensive to buy and run, with even more expensive long-term consequences for people’s health and the environment.

How Trump’s Policies Are Costing Drivers More

As the government relaxes efficiency targets, progress will stall and car buyers will get stuck with cars that cost more to operate.

Energy Innovation, a think tank, found that repealing tailpipe standards could cost households an extra $310 billion by 2050, mainly through more spending on gasoline. Undoing the standards would also increase air pollution and shrink the job market for US electric vehicle manufacturing due to lower demand.

Even the Trump administration’s own analysis of the effects of undoing the EPA’s greenhouse-gas emission regulations found that his moves would drive up gasoline prices due to more fuel consumption from less efficient vehicles.

“Repealing these standards in particular would set America back decades,” said Sara Baldwin, senior director for electrification at Energy Innovation.