My old car was a 1996 Honda Civic. It averaged about 450 km on 40 liters of gas.
My new car is a 2010 Honda Insight. At my last fill-up, I filled 32 liters after 480 km. I've had the car (18 months) and I've driven 30,000 km.
In the last few years gas has averaged around 7.25 NIS a liter.
Today's math question is: How much money have I saved driving my new car?
Old car: 450 km on 40 liters is 11.25km/l
New car: 480 km on 32 liters is 15 km/l
So my new car has used approximately 2,000 liters in the last 18 months. At 7.25 NIS a liter that should be around 14,500 NIS.
My old car would have taken 2,666 liters to drive the same distance. At 7.25 NIS a liter, that would have been 19,333 NIS, for an estimated savings of 4,833 NIS. Cool, right?
Looking at my records, I spent 14,446 NIS on gas since I got the car (and actually drove a bit more than 30,000 km). That works out. But during the final 18 months that I drove my old car, I spent only 14,149 NIS on gas. I had the same job and lived in the same apt. The price of gas was about the same for the last 3 years. What happened?
I'm guessing that, with the expectation that my new car costs less to run, I made more trips. I went to see my son an extra time (he goes to school in the south). I went for shabbat to Jerusalem a few extra times. I had a steady girlfriend who lived in another city for a lot of that time, and that added a weekly trip.
You could say that I got more value from my car. When you spend a resource to get a service, you are not losing anything: you spend $1 of money to get $1 of service. In my new car, I spent about the same amount of money but I got more service - more value for the same money, right?
Still, I can't help feeling that something didn't work out here.