Struggling with math, please help
 

I need some help guys.

Mrs. Spiff complained tonight that she's tired of stopping at the gas station so often and how long would it take a newer, more fuel efficient car, to pay for itself. So I got to work when I got home trying to bring the numbers together.

I have a cost to own spread sheet where I track costs on the cars and know that hers costs $0.12/mile while my focus costs $0.06/mile. Figuring that she won't do as well as mine on the next car due to a more traffic heavy commute I'm guessing the next car will be $0.08/mile. With the value of her car I think we are looking at around $8200 out of pocket for something along the lines of 2014 Hyundai (sister bought one this summer for ~$14,000).

Wife's car is 2005 Subaru Legacy GT that runs on plus/premium, gets a pretty consistent 20.X mpg and she drives 25,000 miles/year. Something like a Hyundai I'm guessing would get 30 on the low side and runs on regular.

I can't wrap my head around the math to figure out how long it would take savings to total $8200. How many miles will the new car have to drive before we ACTUALLY save money? How much would we be saving per month with a smaller gas bill? I'm tired and frazzled and know I should be able to figure this out but something just isn't clicking tonight.

Thanks for any help you can provide.

I get the same 20mpg in my Jeep, and 50 in my Prius.

Over a 200k lifetime, a Prius saves enough that that it will pay for itself even if you buy new. You can have a Jeep sitting and doing nothing but depreciating, and drive the Prius, and be financially equivalent to someone who owns a Jeep only.

Your fuel bill will be less than half.

Not sure I would bother going from 20mpg to 30 though. Get her a Prius. Hypermilers don't need hybrids, but for normal drivers they have bigger gains as they do most of the hypermiling for you.

4 cents per mile saved, $8200... 8200/0.04 = 205,000 miles. Divided by 25,000 miles a year = 8.2 years.

Thanks stubby! that's numbers I had come up with but as I over-thought it, began to doubt myself. Started trying to work in the premium/regular gas argument and just kept getting more confused.

Oldtamiphylie: don't think she'd go for a Prius, not sure I'd go for one either. Still not convinced that the total footprint of the batteries is offset buy the fuel savings. Thanks for the math on that tho showing how something that good can completely cancel out a gas guzzler like a Jeep....or a turbo Subaru

The battery in a Prius is only big enough to power the car 1/2 a mile tops. Yet it saves up to 50% off your fuel bill. The payback would drop to only 4 years.

I bought a Prius because like everyone else, I hated them. I'd suggest test driving one. It's never going to be my favorite car in the world, but sometimes that's exactly what you want.

It is almost never worth buying a different car to save money on gas. I have a similar situation, I drive 30k miles a year and average 25 to 26 mpg over a year.

Do you currently have a car payment?

Don't forget to look at the other costs like insurance and finance charges.

The battery in my Insight, and the older Prius at least, has similar total watt-hours to the 12v battery under the hood. It's more efficient to charge/discharge, lasts longer and can take higher currents, but honestly it's no "bigger" than the lead acid most people throw away every 3-5 years.

Anyway, if you're buying used, the battery is kindof irrelevant unless you plan on buying another one, and most outlast ownership of the car. Is a used Prius (or other hybrid) significantly more expensive than an equivalent used non-hybrid?

~

If I were buying a car in the $3-5000 range (for a non-enthusiast), the only ones I'd really consider would be a Prius or Fit.

If you really shop around, you might be able to find a used Volt close to 8k. While running on electricity, you can expect around 2 cents per mile for the first ~35 miles, and you'll have far lower maintenance needs since the ICE won't be spinning the vast majority of the time.

Lots of people hate Prii. Considering all of the vehicles on the road that are unnecessarily large and powerful, it seems like making a statement is more important than their bank statement. There are other hybrids, but whenever I did the ROI calculations for adding the hybridization, it took a ridiculous number of years. I used to read that it cost $4,000 more. Forbes says $3,000, and most hybrids cost more to own than their gas-only counterpart.

I hope the Lexus LS 600L would not be under consideration, that uses hybridization for speed, with only token fuel economy improvement, but costs $118,537 to own over five years, while the gas-only version would be $90,359. It "would take an owner – and his or her descendants – 151 years to recoup the added up-front cost entirely at the fuel pump." https://www.forbes.com/sites/jimgorz.../#17be6e865d7c

According to Vincentric, only the Toyota Prius C and the Ford Fusion Hybrid save over five years, by roughly one percent each.

As long as the interest rate is at least 1%, I think it makes more sense to purchase the gas equivalent, and pay it off a little sooner. Since there are not non-hybrid versions of the Prii, they compare the C to a Yaris, the " " to the Corolla, and the V also to the Corolla. If you prefer to compare the V to the Camry, the V has an estimated $33,532 cost to own over five years, $29,679 for the Corolla, and $30,361 for the Camry. http://vincentric.com/Portals/0/Mark...ust%202016.pdf

They estimate fifteen thousand miles a year. I do not know how twenty-five thousand yearly would change that, 2/3rds more gas savings, but also a greater depreciation.

I made my own table based on their table:
http://ecomodder.com/forum/attachmen...1&d=1513527577

Time and age are the great equalizers though. After a decade, luxury cars, hybrids and econoboxes all cost about the same.