Fuel Economy Tip - Don’t Use Your Headlights During the Day
July 29th, 2006 | by Brian Carr |Today’s tip will hopefully help you save a bit of money on your car’s gas as well as help your headlights last a little bit longer.
Don’t use your headlights when it’s sunny out.
I got this idea from an article on HowStuffWorks.com, which was about how much gas Americans would waste per year if the Government required all new cars to utilize daytime running lights. According to the article, if every car on the road had daytime running lights, we (Americans) would waste over 406 MILLION GALLONS OF GAS each year!
With gas being roughly $3 per gallon, that would be a loss of over $1 Billion.
While I’m not going to go into how exactly the people at HowStuffWorks.com went about calculating how much gas would be wasted, the logic behind their numbers certainly makes plenty of sense.
With that being said, if you don’t want to add to the amount of gas wasted each year, I would strongly recommend keeping your headlights off during the day, unless it’s raining, you’re driving through a tunnel, etc., or it makes you feel safer to use your headlights all the time.
I certainly don’t think that the savings will amount to much for each individual driver (on average, it’s probably less than $10 per year), but like I’ve said many times before, all those little savings will add up to hundreds or thousands of dollars each year.
9 Responses to “Fuel Economy Tip - Don’t Use Your Headlights During the Day”
By Anonymous on Jul 29, 2006 | Reply
I don’t use my headlights when it’s sunny out, but if that sun goes behind a cloud for two seconds, my headlights are ON. It’s more that I want people to see ME, rather then me being able to see them. That’s just me being over-cautious I guess. If the sun comes back out, my headlights go off. Better safe than sorry, I say.
By Brian Carr on Jul 29, 2006 | Reply
I think that’s a valid point, but at the same time, it’s not like it becomes DARK out when it’s cloudy.
By Anonymous on Jul 29, 2006 | Reply
True, but there is diminished (to a point)sunlight. Like I said, better safe than sorry.
By Anonymous on Jul 31, 2006 | Reply
Visibility > Savings. Savings mean nothing if some guy in a guzzling SUV barrels through your small, gray/silver hatchback on a cloudy day, killing you (okay, the gas you would have used in the future is now saved, maybe that’s what this article was getting at..). Treat everyone else on the road as if they’re blind, as they invariably seem to be. There are safer ways to conserve gas.
By Anonymous on Aug 7, 2006 | Reply
I don’t remember what television program I saw it on, but I remember a few years back I was watching a show and they were explaining how daytime running lights just add to the distractions and something with the way your brain interprets data, actually making it harder to see the other cars on the road if they all had daytime running lights.
I know this sounds like boggled up nonsense the way I explained it, but it made sense on the program.
By Retsudo on Mar 7, 2007 | Reply
I’m pretty sure this is complete horseshit because they make a simple error: thinking that the engine has to run harder to produce more electricity for the lights. That’s wrong. The engine charges up the battery all the time anyway with the alternator. There is no feedback loop that makes the engine rev harder whether or not the lights are on, and the amount of charge produced all the time anyway is plenty to light the headlights.
I could be totally wrong about this but I’m pretty sure I’m not, and having checked a few sources I’m confident that these guys don’t know their ass from a hole in the ground.
By Pal on Jun 8, 2007 | Reply
I think the concept is that electrical use causes the alternator to work harder, as it’s spinning under a stronger load. It’s a pretty small amount compared to the overall load on the engine though. Tire pressure, synthetic oil changes, clean spark plugs, cleaning out junk weight, shifting earlier, neutral coasting, etc all provide mpg boosts well above the electrical load increase on the alternator.
By BH on Jan 24, 2008 | Reply
Retsudo: Both you and your sources are wrong, period. This issue is not open for opinions. The sience and facts are well established since well over 100 years now.
This is the case easy explained. An alternator is basically the same thing as an electric motor. The motor develop a higher output when fed with more electricity whereas the alternator will increase its resistance when you take out more electricity out of it. This is very clear since all cars drop in revs and you clearly can hear the increased workload on the engine when for example the electric cooling fan goes on.
The additional turning force on the alternator required to keep two 55w bulbs is exactly 55 x 2 watts. Nothing less and nothing more. The alternator of course doesn’t give 100% without loss but the losses from the belt and bearings and so fourth is already payed for since it’s there anyway. What I’m talking about is the ADDITIONAL force. 110W exactly.
The battery doesn’t do anything in this formula except smoothen things out a little but it doesn’t produce electricity by itself so it doesn’t help.
Now, how much gas is that? There are just as many answers as there are cars but a rough calculation could look like this. An average car could easily maintain a highway speed on a flat surface using around 40Kw (54HP). It could probably do that using up 0.6 liters in 10 kilometers. 100w / 40000w = 0.0025.
That is 0.25%
So if you drive 20000Km a year you will at best use up only 1200 liters of fuel.
1200 x 0.0025 = 3 liters. Those light bulbs will use up 3 liters which of course isn’t very much. But, if you took these 3 liters multiplied to millions of cars each year the amount of gas would be enourmous.
I’m sorry for using kilowatts, kilometers, liters and so fourth but I’m from sweden and all that gallon, miles, inches and feet stuff doesn’t mean anything to me.
By AC on Feb 4, 2008 | Reply
I’m still a little confused by this. In traditional cars, alternators have a static ability. They produce electricity regardless of wether it’s used or not. It cannot ask for any more power and cant give any unused power back.
Is this still the case for newer cars or do they have fancy gadgets that can increase, decrease the laod on an alternator and thus reduce, increase it efficiency?
If so, this could be were the confusion lays.