Petrol vs Diesel - A Real Life Example!
In one of my very
first newsletters I tackled a personal bug-bear of mine:
Far too many people assume that diesel-engined cars are better because they are more fuel
efficient and therefore cheaper to run than petrol cars.
This is true, BUT petrol cars are generally cheaper to buy than their diesel equivalents and
so for most drivers a petrol car is a better investment.
And I have a very good example to prove my point. Recently, a good family friend was considering
buying an Audi TT and, being a high-mileage driver, assumed that only a 2.0 TDI (diesel) car
would work for her...
WARNING! - If you are allergic to maths, please delete this email immediately...
or go and buy some anti-maths allergy cream from your local pharmacy before proceeding any
THE BASIC INFORMATION
Abigail's dream car = 2008/9 Audi TT
Abi's average annual mileage = 18,000
In the diesel corner...
2.0 TDI - 53 MPG
Cost of a diesel car = £22,000
In the petrol corner...
2.0T FSI - 36 MPG
Cost of a petrol car = £20,000
Expected length of ownership of the car = 2 years
At first glance, this looks like a no-brainer. Abi's high mileage mixed with the huge
difference in fuel economy between the two cars makes it look as if the diesel car is a must.
THE MAGIC OF MATHS
2.0 TDI TT (Diesel) = 53 MPG
18,000 miles = 18,000/53 = 340 gallons
340 gallons = 1,546 litres of fuel per year
Average UK diesel price = 117.8p per litre
TOTAL ANNUAL FUEL COST = £1,821
2.0T FSI TT (Petrol) = 36 MPG
18,000 miles = 18,000/36 = 500 gallons
500 gallons = 2,273 litres of fuel per year
Average UK diesel price = 115.1p per litre
TOTAL ANNUAL FUEL COST = £2,616
DIESEL FUEL SAVING PER YEAR = £795
DIESEL FUEL SAVING, 2 YEARS = £1,590
So, if Abi buys the diesel car she is:
- £1,590 better off in fuel costs after 2 years
- But she had to pay £2,000 extra for the diesel engine
- Overall she is £410 worse off!!
Amazingly, the petrol cars wins!
Of course, the results will vary depending on how long you plan to keep your car, the
price difference between petrol and diesel versions, and the related fuel economy.
Although Abi would have broken even part-way through year 3, a similar calculation we did for
a client buying a Vauxhall Zafira showed that they would finally break even after 53 years...
amazingly, they also opted for a petrol car!