How to use less fuel: practical tips that work
The biggest savings come from how you drive, and they cost nothing. Drive a little slower on fast roads, accelerate gently, keep your tyres at the right pressure, take off the roof box when you're not using it, and combine short trips. With the UK average for petrol at 174.2p a litre and diesel at 199.2p, every litre you don't burn adds up.
Does driving slower save fuel?
Yes, and it is the single biggest change most drivers can make on motorways and dual carriageways. Air resistance rises sharply with speed, so the engine works much harder to go a little faster.
The AA says that driving at 70mph uses up to 9% more fuel than at 60mph, and up to 15% more than at 50mph. Cruising at 80mph can use up to 25% more fuel than at 70mph, and it is also over the speed limit. Dropping from 70mph to 60mph adds about nine minutes to a 60-mile stretch of motorway. Keep to a speed that is safe for the road and traffic, and don't hold up other drivers.
How should I accelerate and change gear?
Smoothly. Hard acceleration and late braking waste fuel. Look well ahead so you can ease off early for junctions, roundabouts and queues, and keep the car rolling where it's safe to do so rather than stopping and starting.
In a manual car, change up early. The AA suggests changing up at around 2,000rpm in a diesel and around 2,500rpm in a petrol. Driving in the highest gear that suits the road and your speed uses less fuel, as long as the engine isn't labouring.
Do tyre pressures affect fuel economy?
Yes. Under-inflated tyres have more rolling resistance, which makes the engine work harder. They also wear faster and affect braking and handling, so this is a safety check as well as a money saver.
- Check your pressures at least once a month and before long trips.
- Check them when the tyres are cold, before you've driven far.
- Use the pressures in your handbook or on the label inside the driver's door or fuel filler flap. Many cars list a higher setting for a full load.
- Never inflate above the maximum pressure printed on the tyre wall.
Does extra weight use more fuel?
It does. The heavier the car, the more energy it takes to get it moving. Clear out anything you don't need to carry, such as sports kit, tools or boxes that have lived in the boot for months.
Roof racks, roof boxes and bike racks are worse, because they add drag as well as weight. Take them off when you're not using them. If you need one for a trip, pack it carefully and keep it as low and narrow as you can.
Is air con or open windows better for fuel?
Air conditioning uses engine power, so it increases fuel use. Around town and at low speeds, opening the windows is usually the cheaper option. At higher speeds, open windows add drag, so the AA's advice is to save the air con for faster driving. Use air con or the demister whenever you need it to keep the windscreen clear, as being able to see comes first.
Other electrical loads cost fuel too. Switch off the heated rear window, demister fan and headlights when you no longer need them, as long as it's safe to do so.
Should I switch off my engine when stationary?
An idling engine uses fuel to go nowhere. The AA suggests switching off if the engine is warm and you expect to wait for around three minutes or more, such as at a level crossing or in stationary traffic, provided your battery is in good condition. If your car has stop-start, leave it switched on.
The Highway Code also says you must not leave your engine running unnecessarily while the vehicle is stationary on a public road, and some councils can fine drivers who refuse to switch off when asked.
How does planning trips save fuel?
An engine uses the most fuel in the first few miles, before it has warmed up. Several short trips from cold use more fuel than one longer trip that covers the same errands.
- Combine errands into one round trip.
- Check traffic before you leave and avoid queues where you can.
- Walk or cycle the shortest journeys if that works for you.
- Know your route so you don't add miles by getting lost.
Does servicing make a difference?
A car that is serviced on schedule, with the correct grade of engine oil and clean filters, runs as efficiently as it was designed to. Use the fuel your manufacturer recommends. If your car is approved for E10, standard unleaded is fine, as our guide to E10 and E5 petrol explains.
Pay less for the fuel you do use
Using less fuel and paying less for it work together. Set up a price-drop email alert and we'll tell you when fuel gets cheaper near you.
Sources
- The AA: Drive smart, save fuel
- Welsh Government: Tackling stationary engine idling
- Live prices: the UK government's Fuel Finder scheme, via Cheapest Fuel. Contains public sector information licensed under the Open Government Licence v3.0.