How to Improve Your Fuel Consumption

What does mpg mean and how is it calculated?

In the UK, we measure fuel economy by mpg (miles per gallon). This indicates how far your car can travel for every gallon (4.55 litres) of fuel it uses. You can compare different cars and engines using the mpg figure to evaluate how efficient they are. Traditionally, diesel cars have a better mpg than their petrol counterparts, but if you’re buying a recent model, the difference between the two is often marginal. Different engine sizes and specs, such as larger wheels, will also affect the mpg of a car.

Car manufacturers use the WLTP (Worldwide Harmonised Light Vehicle Test Procedure) certification to simulate fuel consumption in different scenarios. The combined WLTP figure of a car is the average of four different simulations over different speeds and road types, so it should give you a good indication of its real-world efficiency. But keep in mind that there’s no guarantee that you’ll be able to achieve the mpg quoted by manufacturers, so it should just be used as a guide to compare different models. 

1. Stick to the speed limit

Research has shown that you can use up to 25% more fuel travelling at 80 mph than you do when moving at 70 mph, so going over the national speed limit can really affect your fuel economy. It’s also against the law, so you may get a ticket and that’s not going to help your bank balance either! By driving faster your engine is having to work harder and use more fuel. Use cruise control on flat roads like motorways to help you keep a consistent, fuel-efficient speed. Generally, cars have the best economy when driving at speeds between 45-50 mph.

2. Maintain your vehicle

You should check the tyre pressures on your car every couple of weeks, as both underinflated or overinflated wheels can have a negative impact on your fuel economy. If you regularly take passengers and luggage, the recommended tyre pressure will differ from the lighter load of a sole driver. Take a look in your manual to ensure you have the right pressure for your situation.

Another thing that can help with fuel consumption is regular servicing. Keep up to date with the servicing schedule of your car to improve the efficiency of your engine and reap the benefits of getting more miles to the gallon.

3. Limit use of the air con and heating

If you really want to help your fuel efficiency, think hard about when you need to use your air-con and heating. We’re not saying you should roast when behind the wheel or be so cold you can’t feel your fingers, but using the air con and heating can add strain to the engine and burn more fuel, especially at lower speeds. It’s the same for heated windscreens and other electrical appliances, so keep this in mind if you’re stuck in traffic and don’t really need to use the extra power.

4. Lighten your load

This is an easy one. Do you have a boot full of stuff you keep forgetting to take out? This could be adversely affecting your fuel consumption. The heavier the boot, the more fuel you’ll use carting it about. So next time you go for a trip, get rid of all that excess weight and take only what you need.

5. Reduce drag

Roof bars and boxes can be useful, but they also create drag which will cause your car to use more fuel. The faster you’re driving, the higher the impact on fuel economy. The Energy Saving Trust has estimated that the effect of a roof rack can be as much as 16% drag when driving at motorway speeds, and a roof box creates an incredible 39%. If you’re not using them on your journey, leave them in the garage to get more mpg. Even having your window open at high speeds will create drag that increases fuel consumption, so keep this in mind.

6. Keep the momentum

Keeping to a consistent speed is proven to enhance fuel economy, so we’d recommend driving as smoothly as possible by steering, braking and accelerating gently. Remaining in gear when slowing down will mean you use less fuel when braking. Try to avoid coming to a stop by anticipating what’s happening ahead of you – gradually slowing down at a red light and keeping in motion is better for your fuel consumption than having to fully halt and then accelerate again.

Hills can be a real efficiency killer, so our advice would be to accelerate before you reach one and ease off as you drive up. With that extra bit of momentum, you should be able to avoid using up too much fuel.

7. Change gears early

Driving in built-up areas can have a drastic impact on your mpg, and the best way to minimise the negative impact here is to use your gears cleverly. We’d recommend changing up through your gears as quickly as you can with the lowest possible revs. If you stick to around 2000 revs for a petrol engine and 2500 revs for diesels, you should be running more efficiently. The faster the engine spins by using more revs, the more fuel it will use.

8. Use engine stop/start

If you have a car with stop/start technology, use it to help improve your efficiency. When you come to a stop, get in the habit of moving out of gear and releasing the clutch so that the tech can kick in. Temporarily cutting off your engine like this helps you to save money by preventing fuel from burning unnecessarily.

Small changes make a big difference when trying to get the maximum mpg from your motor. Try out some of our handy tips to improve your fuel consumption, and you’ll be surprised at just how much you can save.