You most likely know by now that fuel efficiency is slated to double in new vehicles by 2025.

What you may not know is how much that will cost you when you buy a new car in future years.

Thousands of real dollars

The EPA has long estimated that a new vehicle will cost about $3,000 more in real (inflation-adjusted) dollars in 2025 than the same vehicle would in 2012.

Now former GM product czar Bob Lutz has weighed in, saying at the Society of Automotive Engineers 2013 World Congress that he thinks the real cost is "on the way to" $5,000.

In his keynote speech, quoted in The Detroit News, Lutz said,  "If the government says $1,800, it'll probably be about double that" by the time new vehicles reach showrooms.

The rules for 2017-2025 that were finalized last year will raise car prices $1,726 on average, while a truck will rise $2,059.

On top of that, there are additional costs for the 2012-2016 rules, agreed to in 2009, that are already being implemented.

Fuel savings much greater

While the average new car now sells for more than $30,000, those increases remain substantial.

Either way, though, the higher cost is far outweighed by the savings in fuel it will provide over the car's lifetime.

Going from, say, 20 mpg to 40 mpg in a car that travels 15,000 miles a year, burning gas at $4 a gallon, saves $15,000 over a 10-year period.

But retail buyers consistently put more importance on initial purchase price (or monthly payment) than on the lifetime operating cost of a new car, even if it costs them money in the long run.

That's why the National Automobile Dealers Association (NADA) was one of the few groups to lobby aggressively against the new rules: Car dealers worried that certain potential buyers wouldn't be able to afford more expensive cars.

42 mpg on window sticker

Under new rules adopted last year by the U.S. Environmental Protection Agency and supported by most (but not all) automakers, corporate average fuel economy (CAFE) will rise to an average of 54.5 miles per gallon across all vehicles.

Gas pump

Gas pump

Because CAFE is measured differently than the EPA gas-mileage ratings, that translates to about 42 mpg on new-vehicle window stickers.

It should be noted that the global auto industry is extremely good at squeezing costs out of mass-produced, highly reliable, complex electromechanical systems and new technologies.

And the industry has a long history of crying wolf over the dire effects of any new regulation, starting with seat belts and working up through emission controls, crash-safety standards, and many more.

Still, there's little doubt that new gasoline and diesel cars will really cost more in real terms as they get more fuel-efficient. (Plug-in electric cars, meanwhile, will slowly come down in cost.)

Is the tradeoff worth it? Are CAFE regulations the right way to improve efficiency and reduce both fuel consumption and vehicle emissions?

Leave us your thoughts in the Comments below.


Follow GreenCarReports on Facebook and Twitter.