Cold snap is draining fuel efficiency and your rand on short trips

South African drivers are seeing fuel bills rise during the country’s cold snap as vehicles become less efficient in low temperatures. The effect is strongest on short trips, where engines and batteries do not reach their optimal operating conditions.

How cold weather reduces fuel economy

According to The South African, cold weather can reduce fuel efficiency by 12% to 20% or more, with the impact worse on short journeys. The report cites research from the US Department of Energy showing that a petrol engine can lose as much as a third of its efficiency on very short trips when temperatures fall.

The article explains several mechanical and environmental reasons for the drop in economy. Engines take longer to reach efficient operating temperature in cold conditions, and thicker fluids increase internal friction. Denser cold air and lower tyre pressure raise resistance and rolling drag, forcing the engine to work harder. The report also says increased electrical loads for heating and defrosting add to energy demand.

Electric and hybrid vehicle impacts

The South African notes that battery performance worsens in cold temperatures, which reduces electric-only range for electric and hybrid vehicles and increases energy demands.

Short trips and stop-start driving suffer most

The article highlights that short trips and stop-start city driving show the largest efficiency penalties, because the vehicle spends most of the trip below its most efficient temperature. It also points out that idling to warm up the car does not improve fuel economy, since fuel is consumed while the vehicle is stationary.

What it costs in rand

According to The South African, at an inland price of R25.58 per litre for 95 unleaded petrol, filling a 45-litre tank costs around R1 151. The publication says that a 15% drop in efficiency would require about 6.75 litres more fuel to cover the same distance, costing an extra R173.

The South African also reports that at R26.17 per litre (wholesale) for diesel, a 45-litre tank costs about R1 178, and a 15% efficiency loss would add close to R177 in extra fuel to travel the same distance.

Practical steps to reduce losses

The article suggests several measures drivers can take to limit fuel and energy losses during cold weather:

• Combine short trips to avoid warming the engine multiple times.
• Avoid excessive idling; drive off gently so the engine warms under light load.
• Check and maintain tyre pressure, which drops in cold temperatures.
• Use block heaters if available.
• Ensure proper battery maintenance and keep up with servicing.

What drivers should take away

Cold weather imposes measurable penalties on both petrol and diesel vehicles and reduces electric range in battery-powered cars. Simple habits and regular maintenance can lessen the impact, but, as The South African reports, many drivers will see higher fuel costs during a cold snap.