As temperatures in the UK soar to 38°C this week, drivers are being warned against a common air-conditioning mistake that wastes fuel. Tim Rodie, Motorpoint’s resident driving expert, says running the air-con on full blast can drain fuel quickly, but simply opening windows at high speeds reduces aerodynamics and also increases consumption.
When to Use Windows vs Air Conditioning
Rodie advises: "As a rule, opening your windows is best when driving around at lower speeds around town and air conditioning is more efficient if you’re on the motorway. So, keep this in mind and be sure to mix it up on long car rides." This simple switch can help motorists go longer between fill-ups.
Don't Idle to Cool the Car
Many drivers leave the engine running to cool the car before getting in, but Rodie warns this is inefficient and risky. "Idling is terrible for fuel efficiency but there’s an even more important reason why you shouldn’t be leaving your car unattended with the engine running when cooling down - the risk of it being stolen." Modern air-con cools quickly, so pre-cooling is unnecessary. Additionally, most insurance policies have 'keys in car' clauses that may void claims if the vehicle is stolen unattended.
Check Air-Con Performance
If the air-conditioning feels "less powerful than normal," Rodie says to get it checked. The system still consumes fuel even when not working properly, so prompt repairs can save money.
Additional Fuel-Saving Tips
Pack Light
Avoid overloading the boot; the lighter the car, the less fuel needed. Rodie adds: "Unless you need the extra storage space, it’s worth travelling without them. They might be a pain to remove but the increased drag and extra weight means your car needs to work harder." This applies to bike racks and roof boxes too.
Plan Your Routes Carefully
Cars burn through fuel in traffic. Map your route to avoid jams, and if stuck in standstill traffic, switch off the engine or use the stop-start function to prevent wasting fuel while idling.
Know Where to Fill Up
Motorway petrol stations charge a premium. Plan your route to fill up at competitive stations, avoiding expensive last-minute stops.
Stick to the Speed Limit and Avoid Flooring It
Speeding not only risks fines but also hurts fuel economy. Speed directly impacts fuel consumption; faster driving means fewer miles per fill-up. Accelerating too quickly also uses much more fuel than smooth driving.
Check Your Tyres
Underinflated tyres increase friction, requiring more fuel. Check tyre pressure at least once a month using a pressure gauge, ensuring it matches the range in your owner's manual.
By adopting these habits, UK drivers can stretch their fuel further during the summer heatwave.
