This couple is saving more than they spent on Tesla Model S

It only takes a 13-mile commute from her home in Carbondale, Colorado (about halfway between Denver and Grand Junction) to her job in Glenwood Springs, for Colleen Farnum's $75,000 Tesla Model S electric vehicle to be a "break-even" proposition. But it turns out that, compared to driving a similar gas-powered car, Farnum and her husband Craig are saving enough money to offset the relatively high price tag of the luxury EV. Not to mention that they can change the diapers of their baby in the luxury EV's "frunk." And that's priceless.

According to a feature in Colorado's Post Independent, the family bought a Tesla Model S 70D this past May and financed it at a low, low rate of 2.2 percent (it's a six-year payment plan). The Model S also generated $13,500 between federal and state tax perks, bringing its out-the-door price to about $61,000. The Farnums' estimated $4,000 in gas and maintenance costs become almost negligible (about $240 a year, actually) with the Tesla. That's due to a combination of the car's 10-year warranty, the growing availability of Level 2 chargers close by and Tesla's expanding Supercharger network for longer road trips through the Rocky Mountain region.

The Farnums previously did a trial run of their break-even test by leasing a Nissan Leaf EV before taking the plunge with the Model S, so they're experienced at this sort of green-car-minded math. With that in mind, they may add another EV in the driveway to see just how far they can drive their savings.

Back in 2013, when Tesla introduced its leasing options, there was a bit of questionable math involved but the overall message was that EVs can be financially sound. The Farnums are living that out.