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As you've probably noticed on your bank statement, car fuel prices are rising faster than Duffy in the Top 40. Last month, diesel prices rose by their highest margin ever this century. At 124.2 pence per litre, says the AA, that makes them the second highest in Europe. And unleaded's now 112.6 pence per litre. Sure, you could drive less. But if that's not an option, check out our top ten tips to drive greener and cheaper.
Here are ten ways to cut your fuel consumption and your carbon emissions. Some of these tips are our own, some are inspired by the Energy Saving Trust's Efficient Driving Tips and the newly launched EU campaign, Save More Than Fuel. The EST reckons you could save £120 a year on your bill.
1. Close your windows on the motorway
Personally, I like having my windows down all the time for fresh air. But if you're driving at high speeds -- 70mph on the motorway, say -- having windows open increases drag, which cuts your fuel economy. Just closing your windows at speed can cut your cut your fuel consumption and carbon emissions by a whopping ten per cent.
21 June 2008 11:02pm
check in at the garage to see if your tyres are under-inflated? or you could just get a tyre pressure gauge...
good tips though. mostly common sense.
24 June 2008 03:59pm
Number one tells you to keep your windows up, and number six tells you to roll your windows down. Which is the lesser evil, I wonder??
24 June 2008 04:46pm
Having your windows shut on the motorway is the way to go -- the saving is 10 per cent on fuel versus 5 per cent for having air con switched off.
In an ideal world, you'd drive on the motorway with your windows shut and the air con off, but obviously that's not much fun when it's really hot.
26 June 2008 07:48am
Not all great recommendations. I drive an 18-year-old lifted Jeep in a very hilly area and I can still get up to 4 mpg over the EPA estimate. I have a lead foot and drive with the windows down all the time. Biggest things are this: Don't use the A/C. Ever. Unless you're about to die it's so hot. If you have a manual (which I think more people should), use neutral as much as you can. Pop it into neutral on downhills or coming to stops (waaaaaaaay back, not 50 feet from the light). On hills, don't leave it in a high gear, downshift so that you can push the gas down less. Even though it's more RPM, the added HP from higher RPM makes you use less gas. Oh yeah, be smooth with the gas. Even if you floor it, just don't do it suddenly. It works. Seriously.
26 June 2008 07:49am
Oh, but the car-pooling, air pressure, and roof rack are good recommendations, too. The weight doesn't make a noticeable difference unless you're hauling bricks around.
28 June 2008 05:52pm
At slower speeds, windows are better than air conditioning, at faster speeds, it's the other way around. Ideally, keep the windows up and the A/C off.
28 June 2008 07:46pm
Yes, all these are common sense (although most drivers seem not to have any!). The biggest way to improve your fuel economy is to NOT drive your car unless you absolutely have to! Plan ahead and consolidate trips. Take public transportation. Ride a bike. But if you do have to drive, these are good. If you do roll up the windows, don't run the AC, because running the AC burns more petrol than rolling down a window (Mythbusters).
28 June 2008 10:14pm
what you want to do is look at the front of your car. What you see is what is exposed to the wind, which will causes the resistence of your car moving through air. So having your windows open does not matter. It actually helps your car move through the air better. However if their is a cross wind then you should really shut your windows.
28 June 2008 10:39pm
Anonymous User above obviously has no clue about aerodynamics. If having your windows open doesn't add drag, how is all that fresh air coming into your car??
02 July 2008 03:55pm
While anon immediately above is correct, anon above him is not entirely incorrect. The drag coefficient goes normally up with open windows as it disturbs the airflow. But how much so is a function of apparent wind speed and direction. The functions form depends on the aerodynamics of the car as the airflow changes at different speeds. If the makers were clever with the aerodynamics you may have the wind flows through the car nicely at high speed and then it should be much more efficient than aircon.
I used to have a old Ford with a plastic air diverter fitted to the drivers side. Opening the window on a motorway resulted in an amazingly low flow of air. However when I removed the diverter (as I accidentally bust it earlier) opening the window caused crazy amounts of airflow and passengers to shout "close the window!"
29 July 2008 06:42pm
Anononymous [American]
Who drives an:
'18-year-old lifted Jeep in a very hilly area and I can still get up to 4 mpg over the EPA estimate. I have a lead foot and drive with the windows down all the time. Biggest things are this: Don't use the A/C. Ever. Unless you're about to die it's so hot. If you have a manual (which I think more people should), use neutral as much as you can. Pop it into neutral on downhills or coming to stops (waaaaaaaay back, not 50 feet from the light).'
Anonymous thinks that coasting in neutral is a good idea. First I believe it's illegal in the UK, because of the reduction in control, if hard braking is required. The drive wheels may lock-up. Secondly, all modern cars have a fuel shut-off valve that shuts off the fuel to the engine when the engine is in gear, the foot is off the throttle and the wheels are overrunning the engine, [may not be true for an 18-year old Jeep]. This means that coasting in neutral will use MORE fuel than taking one's foot off the throttle with the engine in gear [zero fuel], because the engine is turning through the declining kinetic energy of the vehicle.
The important ways to save fuel are to keep the vehicle well maintained.
Tyres properly inflated.
Use the correct gear, not too high or too low.
Maintain RPM near 2000 for petrol ~ 1500 for diesel.
Anticipate road conditions and take your foot off the accelerator when there's a hold-up ahead.
Take off the roof rack if your not using it.
Empty the boot.
Try and remain relaxed when driving.
Avoid listening to music that makes you drive faster.
Cycle or walk for short journeys.
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