How to Save Money by Greener DrivingFebruary 16, 2011
How to Save Money by Greener Driving
This guide shows you how to save money, especially on petrol and diesel, by greener driving, in the areas of buying, driving, running, and lifestyle.
The goal: To enjoy a car with low fuel consumption and low emissions.
Cars that use less fuel are cheaper to run. To save money on fuel, focus on a car’s fuel consumption (miles per gallon, or mpg) – the higher the mpg figure the lower (or better) the fuel consumption. Our Green Car Guide recommends the most economical cars in different categories – as long as they are also good cars!
All conventional cars give out carbon dioxide (CO2), the main gas that contributes to climate change, and toxic emissions such as nitrogen oxide (NOx). A high miles per gallon figure will translate into low emissions (expressed as grammes per kilometre of carbon dioxide, or g/km CO2).
Since 2001, cars in the UK have had their tax (vehicle excise duty) based on their carbon emission figure and the type of fuel that they use. A more economical car can currently save the owner hundreds of pounds in car tax each year. This differential is set to increase.
The Vehicle Certification Agency guide ( www.vcacarfueldata.org.uk ) provides information on the fuel economy and emissions performance of all new cars on the market in the UK.
New cars get tested to make sure their exhaust emissions meet European standards, which have been getting stricter since the 1990s.
Since 1992, all new petrol cars have had to have a catalytic converter fitted. A catalytic converter is a device located in the exhaust system of all cars and most light trucks. It chemically converts pollutants like carbon monoxide, hydrocarbons and nitrous oxides into substances like carbon dioxide, nitrogen and water vapour. A converter uses an inside structure called a substrate that is plated with precious metals such as platinum, palladium and rhodium. These elements cause the chemical change. Catalytic converters came in as a result of the Euro I standard. The Euro V standard came into force in September 2009 for all new cars. So the newer the car, the better for the environment. One pre-1992 car without a catalytic converter gives out roughly the same emissions as 20 of today’s new cars.
So here are our tips for how to enjoy maximum fuel economy and lowest emissions.
Small cars need less energy to make them move, therefore they are more fuel efficient and produce lower emissions than large cars; a car such as the smart fortwo cdi delivers 83 mpg. However, as anyone who’s been in a two-seater smart car will testify to, there isn’t much room! For the average family, cars such as this just aren’t a practical proposition. This leaves a range of ‘slightly larger’ small cars such as the Volkswagen Polo BlueMotion; this diesel model returns 80 mpg.
Conversely, the worst cars for energy efficiency are ‘SUVs’. Just like the vehicles themselves, the term ‘Sports Utility Vehicle’ has come over from the States. In America, SUVs are typically four-wheel drive pick-ups or estates with massive V8 petrol engines that return around 15 mpg. Petrol, or ‘gasoline’, has historically been relatively cheap in America, although this has recently been changing, therefore this has not been a barrier to people buying energy-inefficient vehicles, even though they may have no real need for a pick-up truck. The influence that motor manufacturers and oil companies have had on American politics encouraged this situation.
The SUV vehicle market has grown dramatically in Europe over the last few years, although they are usually more energy-efficient diesel varieties than those in America. The use of ‘SUVs’ in urban areas and for the school run is on the hate list of anti-4×4 campaigning groups. So unless you really need and use a car that can negotiate a muddy field, it’s probably best to avoid a large off-roader and so save money at the pumps.
Of course, there are plenty of large vehicles that aren’t SUVs, including large saloons, estates and MPVs, or ‘people carriers’. These are obviously less efficient in terms of economy than their smaller counterparts. If you need a larger car, check our Green Car Guide to find the most economical choice – similarly-sized cars can vary in fuel efficiency by up to 45%!
Lighter objects need less energy to make them move, and cars are no exception to this rule. That’s why a smart car can achieve over 80 mpg, yet a Range Rover will struggle to average more than 25 mpg.
Petrol was the most popular fuel for cars in the UK for years; petrol engines are generally quiet and smooth, and their performance is good. Petrol is currently slightly cheaper than diesel. Petrol engines emit around 10% more carbon dioxide (CO2) than diesel. However petrol cars pump out less toxic emissions than diesel. Petrol engines are generally more responsive than diesel, and have traditionally offered the best choice for the average driver.
Diesel engines are more economical than petrol engines, therefore they emit less CO2. New ‘common rail’ diesels are approximately 10% more efficient than older diesels, and direct-injection diesel engines give the best fuel economy. Diesel engines with a particulate trap help prevent emissions of sooty particulates – ie. the clouds of smoke that you’ll experience if you follow old buses through towns. So diesel engines will generally provide you with more miles per gallon than their equivalent petrol models – just look at the differences between similar vehicles in our Green Car Guide. Diesel engines have traditionally been used predominantly in larger/heavier vehicles such as 4x4s. Over recent years they have appeared in smaller cars, and are particularly well suited for drivers who do high motorway mileages as they return good economy figures and are generally robust and durable over high mileages.
Over recent years, LPG (liquefied petroleum gas) has been a viable fuel option in the UK. LPG produces fewer emissions than petrol and diesel but fuel consumption is worse. It’s been possible to convert many existing cars to run on LPG by after-market conversions, and some manufacturers such as Vauxhall have had new cars in their range that are dual-fuel, which are designed to run primarily on LPG with petrol back-up. There is a reasonable network of filling stations.
LPG, and natural gas in heavier vehicles, has been an attractive proposition in the past primarily due to its cheaper cost, as it has enjoyed less fuel duty. However there is no guarantee that the Chancellor will maintain this in the future, and although there are some emissions improvements over petrol, LPG is still derived from a fossil fuel and therefore still releases greenhouse gases into the atmosphere.
Some vehicles, usually heavier vans or trucks, can run on CNG (Compressed Natural Gas), which again results in lower CO2 emissions than standard petrol cars, but the fuel is not as efficient as diesel. Finding LPG and CNG for refuelling can be a challenge.
Regardless of which fuel you use, some engines are inherently more economical than others. For example the previous generation Ford Ka, although it was great fun to drive, for most of its life was always been restricted by old engine technology to prevent it competing too closely with the Fiesta, which benefited from newer, higher-tech engines and therefore much better fuel consumption. See our Green Car Guide to see which cars are the most efficient.
Today we are right at the point where motor manufacturers are having to develop innovative technology to achieve much greater improvements in fuel economy. There is one technology in particular that is rapidly being adopted – the ‘petrol-electric hybrid’.
Hybrid vehicles run on a combination of a conventional petrol engine and an electric motor powered by an energy storage device such as a battery pack. Hybrids use regenerative braking, which means that energy is put back into the battery when braking, which improves energy efficiency.
Hybrid technologies improve fuel efficiency and therefore provide considerable fuel savings compared with a normal petrol vehicle. While hybrid models might cost between £1,000-£3,000 more than conventional cars, running costs can be two-thirds that of equivalent petrol-fuelled vehicles.
Hybrids are a great choice if you do much city driving, however they may not be as economical as a good diesel if you do lots of motorway miles.
‘Stop & Start’ technology is now becoming very common on new cars – when stopped in traffic, the car’s engine cuts out. While you still pay a premium over standard models, they are cheaper than hybrids – but the fuel savings are not as great; like hybrids, they offer greatest benefit in urban areas.
A range of new electric vehicles is now appearing, such as the Nissan LEAF. Electric cars use a battery and electric motor to power the vehicle, meaning they have no emissions at the point of use. Due to the capacity of the battery, their range is normally limited to about 100 miles or less between recharges, which means they are only really suitable for city-based users.
Electric vehicles can be recharged by plugging them into an existing electrical socket, and some areas are installing electric recharging points in car parks or on- street. However, they are only truly ‘green’ if they are recharged with electricity from renewable sources such as wind farms.
The technology of electric cars is still in its relative infancy. Electric cars make more sense if you commute short distances in areas such as London’s congestion charge zone.
The next big thing will be range-extended electric vehicles such as the Vauxhall Ampera. These are primarily electric vehicles, but with an on-board range-extender generator to give extra range – in most cases this generator is likely to be a small petrol engine, but it could be something completely different – such as the gas turbines in the Jaguar C-X75 concept.
Manual or automatic?
Automatics, much loved by Americans, can use 10% to 15% more fuel than manuals. Cars with continuously variable transmission (CVT) can use 5% to 7% more fuel. Therefore avoid being lazy and choose a manual transmission!
On motorways, fuel consumption evens out so there’s less difference between manuals and automatics. Modern semi-automatic features such as button-operated gear change and automatic clutch control help you use less fuel. Some of the very latest automatics can be just as economical as manuals – or even better.
The added weight of the components and the energy needed to overcome the extra resistance means that cars with four-wheel drive are less economical than their two-wheel drive counterparts. Fuel consumption can be up to around 10% worse than for a similar sized two-wheel drive vehicle. Many 4x4s are also heavier vehicles anyway, with poor aerodynamics, helping to further deteriorate their fuel consumption.
However there must be a reason why vehicles such as Subarus are so popular in places such as Scotland and New Zealand, ie. places with mountains and snow – because they are all-wheel drive it means they have much better traction and safety than rear-wheel drive cars, which are prone to oversteer on their limit in corners, and than front-wheel-drive cars that tend to understeer. Therefore for people who need them, the sooner that more fuel-efficient 4x4s are available, the better – and it’s happening now.
Driver and Vehicle Licensing Agency (DVLA) www.dvla.gov.uk based in Swansea, Wales provides legal answers to questions related to taxation and other vehicle regulations.
The London Congestion Charge www.cclondon.com may be fully discounted for some classes of vehicles or users, although there is a small annual registration fee.
The Vehicle Certification Agency (VCA) www.vca.gov.uk tells you the Excise Duty when you specify the vehicle model.
Buy a car with a fuel consumption display
Toyota or Lexus hybrids have information screens showing a detailed mpg summary, which makes you want to keep beating your last figures and drive more economically!
Think about the manufacturing
Lots of energy is expended during a car’s manufacturing, so try to pick a car manufacturer with a track record of good environmental performance.
No matter what the weight of their car, some people just make their cars even heavier by carrying lots of unnecessary things – thereby needing more energy to make the car move. This also includes carting around heavy people – if they’re just being a dead weight and making you use more fuel – get them to walk instead! Remember that if carrying extra weight, your tyre pressures should be higher – see your car’s manual.
Anything that interrupts the smooth flow of air past your car needs to be addressed. The obvious culprit here is roof racks/luggage carriers/roof boxes. You may think that carrying skis around on your roof all year round makes you look cool and trendy but it’s just burning a hole in your wallet and the ozone layer – take roof racks off if not in use. Windows are also bad! – open windows drastically reduce your fuel efficiency – so keep them closed unless you’ve got a very good reason to keep them open.
If you really must tow a caravan or high trailer, then apart from annoying every motorist behind you, you’re fighting the first two principles of fuel efficiency – low weight and good aerodynamics – consider fitting an aerofoil to the roof of your vehicle to minimise wind resistance.
Finally, body kits or extras that are added to the outside of a vehicle will also affect the aerodynamics of the car and contribute to extra weight. But more importantly body kits look rubbish so just avoid them completely. Manufacturers spend millions of pounds designing cars – why ruin them with a body kit?
If you follow the above advice and don’t open your windows, you’ll be tempted to use the air conditioning to cool down – well think again. Air conditioning can increase fuel consumption by 10%, although the impact will be less if travelling at a constant speed on the motorway. So keep those fresh air vents open and wear minimal clothing when driving in summer! All accessories can drain energy and use more fuel, even the rear screen demister or the radio. If you want to be really super-keen, then in winter see if you’ve got the willpower to avoid turning on the engine and using the windscreen demister, and scrape off the ice or use a de-icer. An easier option may be to buy an insulating cover for the windscreen or keep the car undercover in the winter.
No surprises that there’s a direct link between burying your right foot on the accelerator and the amount of fuel burnt! Aim to perfect the art of gentle pressure on the accelerator and keep speeds down to achieve maximum mpg. Doing this could easily save hundreds of pounds per year. The faster you go over 70mph, the more the fuel burns away…
Accelerating harshly then braking like a mad person is a sure way to devour the contents of your fuel tank, as well as ensuring you’ve got no brake disks or tread left on your tyres – as well as scaring passengers. By thinking and planning ahead you can apply light throttle and avoiding heavy braking, so reducing both fuel consumption and wear and tear. Try to predict traffic at junctions and when in queues avoid accelerating and then braking harshly. Driving techniques can affect car fuel efficiency by as much as 30 percent. Advanced driving techniques will help with smooth driving and will make you a safer driver – see www.iam.org.uk
Driving in the highest gear possible without labouring the engine is a fuel-efficient way of driving. A car travelling at 40 mph in third gear can use 25 percent more fuel than at the same speed in fifth gear. The fuel saving of coasting downhill in neutral or with the engine off will be negligible, but as the car will be out of control this can result in instant death, therefore this is not recommended.
Stop and switch off
If you stop for more than a few minutes, switch off your engine – this is the ultimate in economy as you’re using no fuel at all! However switching off your engine for short periods of time can increase fuel consumption, as it requires more fuel to get the engine started. Also your catalytic converter may no longer be running at full temperature, so your car will be less efficient, increasing the amount of pollution produced. Many manufacturers are now introducing stop-start systems on their models.
Drive off promptly
After starting your car, rather than leaving your engine running, drive off as soon as possible to prevent wasting fuel. And to save money on replacing a worn-out engine, drive gently until the engine has reached its normal operating temperature.
3. Running your car
Most people don’t seem to have a clue as to whether the petrol they are buying is cheap or expensive relative to other garages. So keep your eyes open and shop around for cheaper petrol – supermarkets can be at least 4 pence per litre cheaper than normal garages, and overall the difference between garages can be as much as 10p per litre!! But don’t drive miles out of your way to find cheaper petrol as it will end up costing you more in fuel than the money you will save. For the cheapest petrol in your area check out www.petrolprices.com
If your tyres are under-inflated, you will use more fuel. This will also increase the rate of wear, which will also cost you more money. And apart from all that, it will affect your car’s handling and therefore safety. Remember it’s just those four patches of rubber that keep your car in contact with the road – a scary thought if driving a people carrier full of kids on under inflated-tyres. And it’s estimated that about 50% of tyres on the road are under-inflated. Therefore tyre pressures should be checked against the recommended pressures regularly, ideally every one to two weeks.
Worn tyres will also decrease fuel efficiency, and impact on your safety again, so check the tread regularly. If you are replacing tyres then consider some of the newer ‘Eco’ tyres that are designed specifically to increase fuel efficiency.
Regular servicing of your car at the manufacturer’s recommended service intervals will help to ensure it’s running at its optimum efficiency. In particular, the following areas can make a big difference:
One of the most common reasons for a drop in fuel efficiency is a dirty intake filter. This will decrease the amount of air entering the cylinders of the engine resulting in incomplete combustion. Check the filter regularly to ensure that it is clean.
Ensure your spark plugs are in good condition. Renew the plugs and wires at intervals specified by the owner’s manual. This will keep all cylinders firing properly resulting in higher efficiency.
Change the lubrication oil at intervals specified by the owner’s manual. Use only the recommended oil, especially in newer cars. Use of an engine flush before changing the oil will help to get rid of a lot of the dirt that collects in the engine that a normal oil change will not remove. On older engines it is advisable to use an oil treatment agent. This basically thickens the oil, which creates a better seal between the piston and the liner, preventing blow past and consequent loss of combustion pressure, resulting in higher fuel efficiency.
Replace exhausts with the type recommended by the manufacturer.
Full Service History
Older cars that haven’t been looked after well will also fall short of their stated mpg. If buying one, look for a full service history.
Don’t use your car!
Here’s a sure-fire way to use less petrol – don’t drive anywhere! Probably the best way to decrease the amount of petrol you burn is to leave the car at home, and take a bike, bus or train, or walk. A quarter of all car journeys in Britain are less than two miles long, and walking or cycling are cheap, clean and healthy alternatives.
Don’t use your car for short journeys
Short journeys waste more fuel than long journeys, so consider combining a number of stops if going out.
Avoid travelling in rush hour traffic
Sitting in rush hour traffic causes pollution, wastes fuel, time and money, and generates stress. So avoid travelling in rush hour traffic if possible – set off early or late, or work from home if you’re able to. And getting lost and driving around the M25 twice isn’t a smart idea! Planning a quiet route that allows you to drive at a constant 50-60mph and avoids stop-start traffic will maximise fuel efficiency.
Lots of cars carry only one person, so sharing car journeys with other people and using what would normally be free seats in a car can be a simple way of cutting the cost of driving and reducing congestion and pollution.
Liftsharing can happen informally, where friends, family or neighbours take turns to give each other lifts, or more formally through the increasing number of company or council-run schemes, or through on-line services such as www.liftshare.org . On this site, users register regular or one-off journeys they are about to take and they’re put in contact with other people who are making a similar journey. Drivers are not permitted to make a profit from providing a lift, but a contribution from passengers can include an appropriate amount towards wear and tear. ‘Fares’ must be decided in advance, and the driver is not allowed to act as a taxi, picking up strangers along the route.
The idea of car-pool clubs is that rather than owning a car that you use only occasionally, people club together to share a pool of cars. You pay annually or per use, free from the worries of ownership, depreciation and servicing. If you drive less than 6,000 miles in a year, joining a car club could save you between £1,000 and £1,500 a year, according to the organisation Carplus. Car clubs are typically run by local councils or private businesses and allow the short-term hire of cars, freeing members up from car maintenance and tax costs.
This ‘pay-as-you-go’ approach to driving also reduces the amount of unnecessary car journeys, helping to combat pollution and congestion. Drivers pay a joining fee, a deposit, and hourly charges. In addition, there’s a fuel charge per mile. Typically, once you are a member of a club, you simply book the time you need, enter a pin to access the car and then drive off.
At www.carplus.org.uk you can find car clubs in your area or check out the guidance it offers on starting your own informal car club.
City Car Club www.citycarclub.co.uk has cars in reserved parking bays in locations nationwide.
Keep a car longer
This reduces the environmental impact of manufacturing – however remember that newer cars have improved emissions.
But when the time finally comes…
Even after you have finished with your car you can be environmentally-friendly. If your car is too old or too damaged to be sold on, the End of Life Vehicles Directive will make sure that your car does not continue to pollute the earth after it has stopped being useful.
All the above tips will help you maximise your fuel economy, but the biggest impact on fuel consumption will be the type of car you buy. To find the most economical car for you, check out our Green Car Guide .