Petrol vs diesel – How much you actually save

Diesel engines are incredibly efficient, which can make a big difference to your fuel bill at the end of the month.

However, they often come at a substantial premium over their petrol counterparts, which raises the question of how much driving you’ll need to do before you actually start saving any money.

Upfront costs vs long-term savings

The most affordable crossover in South Africa that has access to both petrol and diesel drivetrains is the Kia Seltos.

The base models are fitted with a 1.5-litre petrol block, which generates 84kW and 144Nm.

The diesel engine is the same size but incorporates a turbocharger, letting it put out 85kW and 250Nm.

Of course, the real value of the less refined liquid is its fuel efficiency, as it consumes just 5.2l/100km compared to the petrol’s 6.3l/100km

The following table shows how much fuel the two models will use over the course of 1,000km, and how much it will cost at the pump

The expenditures are calculated based on the latest fuel price adjustments as of October 2024, as petrol 95 is currently retailing for R21.05 per litre, while diesel 0.005% goes for R18.57 per litre.

This works out to a respectable fuel-saving of R360.51 per 1,000km, but we now have to look at the cost difference between the two cars.

The price of the two models being compared is listed below:

• Kia Seltos 1.5 LX Auto – R492,995
• Kia Seltos 1.5CRDi LX Auto – R521,995

Given the relatively high asking price to begin with, the difference actually isn’t that high, only clocking in at R29,000.

We can use these two values to work out the distance an owner will need to cover to start saving money with their diesel purchase.

What this shows is that buying a more fuel-efficient car is a long-term commitment, as you won’t be reaping the benefits to your bank account until you’ve driven for several thousand kilometres.