# Does the use of a radio increase a car's fuel consumption? **URL:** \ **Category:** Factual Questions\ **Created:** [April 21, 2008, 9:18pm UTC](https://boards.straightdope.com/t/does-the-use-of-a-radio-increase-a-cars-fuel-consumption/446309 "2008-04-21T21:18:52Z")\ **Posts on this page:** 16\ **Page:** 2
**Author:** ![Harmonious\_Discord](https://avatars.discourse-cdn.com/v4/letter/h/74df32/32.png) [@Harmonious\_Discord](https://boards.straightdope.com/u/Harmonious_Discord)\ **Post date:** [April 22, 2008, 3:02pm UTC](https://boards.straightdope.com/t/does-the-use-of-a-radio-increase-a-cars-fuel-consumption/446309/21 "2008-04-22T15:02:29Z")
Just to be clear by reducing weight I was referring to all ways to lessen the weight. Instead of the nightly gas price change on the news they can tell you that removing the bag of kitty litter will save a certain amount of gas. ---
**Author:** ![YamatoTwinkie](https://avatars.discourse-cdn.com/v4/letter/y/cc9497/32.png) [@YamatoTwinkie](https://boards.straightdope.com/u/YamatoTwinkie)\ **Post date:** [April 22, 2008, 8:14pm UTC](https://boards.straightdope.com/t/does-the-use-of-a-radio-increase-a-cars-fuel-consumption/446309/22 "2008-04-22T20:14:24Z")
[QUOTE=Sam Stone] Headlights consume between 35 watts (HID) and 55 watts of power, typically. A gallon of gas burned through a 100% efficient generator could run your headlights for about 60-100 hours. [/QUOTE] Hmmm. . . Energy content of a gallon of gasoline is 131MJ, if [wikipedia](http://en.wikipedia.org/wiki/Gasoline#Energy_content) is to be believed. That converts to 36389 Watt-hours of energy. Dividing that by 55 watts yields **662** hours. You sure your math is right? or did you use something other than a 100% efficient generator? ---
**Author:** ![Rick](https://avatars.discourse-cdn.com/v4/letter/r/9f8e36/32.png) [@Rick](https://boards.straightdope.com/u/Rick)\ **Post date:** [April 22, 2008, 11:05pm UTC](https://boards.straightdope.com/t/does-the-use-of-a-radio-increase-a-cars-fuel-consumption/446309/23 "2008-04-22T23:05:58Z")
[QUOTE=Una Persson] Remember that you don’t typically drive around at wide-open-throttle, you tend to drive around at the power needed to overcome rolling resistance and wind resistance. In some cars that can be as little as 5-20hp for a low-speed cruise. The radio power is still a small number, but a larger percentage. [/QUOTE] Along the same line, you typically don’t listen to your radio at 100% of it’s rated power output either. About headlight wattages. The 35 and 55 watts quoted is per headlight. Double it for the per car figure, unless you drive around with one headlight out. If you do this, shame on you. ---
**Author:** ![Turek](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/turek/32/18782_2.png) [@Turek](https://boards.straightdope.com/u/Turek)\ **Post date:** [May 27, 2013, 10:39am UTC](https://boards.straightdope.com/t/does-the-use-of-a-radio-increase-a-cars-fuel-consumption/446309/25 "2013-05-27T10:39:27Z")
Reported ---
**Author:** ![bob\_2](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bob_2/32/3341_2.png) [@bob\_2](https://boards.straightdope.com/u/bob_2)\ **Post date:** [May 27, 2013, 11:16am UTC](https://boards.straightdope.com/t/does-the-use-of-a-radio-increase-a-cars-fuel-consumption/446309/26 "2013-05-27T11:16:19Z")
According to a report I read, the introduction of DRL (Daytime Running Lights) in the EU would cost around 10 million Euros annually due to increased fuel consumption. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [May 27, 2013, 2:11pm UTC](https://boards.straightdope.com/t/does-the-use-of-a-radio-increase-a-cars-fuel-consumption/446309/27 "2013-05-27T14:11:25Z")
Power doesn’t come from your car battery. Or rather, it does, but that’s not ultimately the source. Your battery is continually receiving power from the alternator, which receives it from the engine, which receives it from the fuel. ---
**Author:** ![johnpost](https://avatars.discourse-cdn.com/v4/letter/j/f17d59/32.png) [@johnpost](https://boards.straightdope.com/u/johnpost)\ **Post date:** [May 27, 2013, 2:31pm UTC](https://boards.straightdope.com/t/does-the-use-of-a-radio-increase-a-cars-fuel-consumption/446309/28 "2013-05-27T14:31:48Z")
zombie or no if the radio is turned up loud then it caused your car to vibrate ever so slightly disrupting the air flow causing turbulence. ---
**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\ **Post date:** [May 27, 2013, 3:26pm UTC](https://boards.straightdope.com/t/does-the-use-of-a-radio-increase-a-cars-fuel-consumption/446309/29 "2013-05-27T15:26:18Z")
> [@johnpost](#): > > zombie or no Note: Bumped by spammer. ---
**Author:** ![Johnny\_L.A](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johnny_l.a/32/1084_2.png) [@Johnny\_L.A](https://boards.straightdope.com/u/Johnny_L.A)\ **Post date:** [May 27, 2013, 3:36pm UTC](https://boards.straightdope.com/t/does-the-use-of-a-radio-increase-a-cars-fuel-consumption/446309/30 "2013-05-27T15:36:59Z")
My Prius burns more fuel per mile in Winter than in Summer. There’s a thread on it somewhere, but I’m not going to look for it. I _think_ the conclusion was that the main cause of the reduced mileage was that cold air is more dense than warm air, so more fuel has to be added to the mixture to maintain the proper ratio. But when I’m driving in Winter, the heater, headlights, and windshield wipers are on constantly. I’ve noted, by watching the instant mileage readout, that the car says it is getting more miles per gallon when accessories are off; but it’s not possible to know whether this is ‘real’, or if I just happen to be looking when the slope of the road is favourable. ---
**Author:** ![Procrustus](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/procrustus/32/2994_2.png) [@Procrustus](https://boards.straightdope.com/u/Procrustus)\ **Post date:** [May 27, 2013, 3:48pm UTC](https://boards.straightdope.com/t/does-the-use-of-a-radio-increase-a-cars-fuel-consumption/446309/31 "2013-05-27T15:48:51Z")
> [@Johnny\_L.A](#): > > My Prius burns more fuel per mile in Winter than in Summer. There’s a thread on it somewhere, but I’m not going to look for it. I _think_ the conclusion was that the main cause of the reduced mileage was that cold air is more dense than warm air, so more fuel has to be added to the mixture to maintain the proper ratio. But when I’m driving in Winter, the heater, headlights, and windshield wipers are on constantly. I’ve noted, by watching the instant mileage readout, that the car says it is getting more miles per gallon when accessories are off; but it’s not possible to know whether this is ‘real’, or if I just happen to be looking when the slope of the road is favourable. The batteries are more efficient in warmer weather. A more important factor is the gas engine runs more in the winter so you can have heat. In the warm weather, you’re cruising around just on the battery more of the time. ---
**Author:** ![Senegoid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/senegoid/32/6606_2.png) [@Senegoid](https://boards.straightdope.com/u/Senegoid)\ **Post date:** [May 27, 2013, 4:52pm UTC](https://boards.straightdope.com/t/does-the-use-of-a-radio-increase-a-cars-fuel-consumption/446309/32 "2013-05-27T16:52:30Z")
> [@brewha](#): > > If you have 4 20" subs with a couple of thousand watt amps it’ll be a little more obvious. I swear, this must be all too common. There are certain tenants (and/or visitors) who park outside my apartment, whose rolling concert halls have woofers that literally shake my windows and walls. I’d love to get a bazooka and blow those cars to smithereens – but I imagine that would be little more than a little extra background noise on top of what’s already there. ---
**Author:** ![Johnny\_L.A](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johnny_l.a/32/1084_2.png) [@Johnny\_L.A](https://boards.straightdope.com/u/Johnny_L.A)\ **Post date:** [May 27, 2013, 7:53pm UTC](https://boards.straightdope.com/t/does-the-use-of-a-radio-increase-a-cars-fuel-consumption/446309/33 "2013-05-27T19:53:01Z")
> [@Procrustus](#): > > The batteries are more efficient in warmer weather. A more important factor is the gas engine runs more in the winter so you can have heat. In the warm weather, you’re cruising around just on the battery more of the time. That sounds familiar. Thanks. ---
**Author:** ![panache45](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/panache45/32/64_2.png) [@panache45](https://boards.straightdope.com/u/panache45)\ **Post date:** [May 27, 2013, 9:44pm UTC](https://boards.straightdope.com/t/does-the-use-of-a-radio-increase-a-cars-fuel-consumption/446309/34 "2013-05-27T21:44:10Z")
> [@johnpost](#): > > zombie or no > > if the radio is turned up loud then it caused your car to vibrate ever so slightly disrupting the air flow causing turbulence. If you move around with the music you’ll be burning calories. So you’ll weigh a little less, increasing the car’s efficiency. ---
**Author:** ![Jeff\_Lichtman](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jeff_lichtman/32/1531_2.png) [@Jeff\_Lichtman](https://boards.straightdope.com/u/Jeff_Lichtman)\ **Post date:** [May 27, 2013, 11:57pm UTC](https://boards.straightdope.com/t/does-the-use-of-a-radio-increase-a-cars-fuel-consumption/446309/35 "2013-05-27T23:57:58Z")
> [@Johnny\_L.A](#): > > My Prius burns more fuel per mile in Winter than in Summer. . . Winter-blend fuel in California gives lower gas mileage than summer-blend fuel does. I don’t know about other states. ---
**Author:** ![jz78817](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jz78817/32/1028_2.png) [@jz78817](https://boards.straightdope.com/u/jz78817)\ **Post date:** [May 28, 2013, 12:27am UTC](https://boards.straightdope.com/t/does-the-use-of-a-radio-increase-a-cars-fuel-consumption/446309/36 "2013-05-28T00:27:31Z")
> [@Johnny\_L.A](#): > > My Prius burns more fuel per mile in Winter than in Summer. There’s a thread on it somewhere, but I’m not going to look for it. I _think_ the conclusion was that the main cause of the reduced mileage was that cold air is more dense than warm air, so more fuel has to be added to the mixture to maintain the proper ratio. But when I’m driving in Winter, the heater, headlights, and windshield wipers are on constantly. I’ve noted, by watching the instant mileage readout, that the car says it is getting more miles per gallon when accessories are off; but it’s not possible to know whether this is ‘real’, or if I just happen to be looking when the slope of the road is favourable. part and parcel of hybrids. Well, actually, any car, but the difference is more noticeable with hybrids. reasons being: 1. when you start out your traction battery is cold, so it isn’t able to contribute as much until the cells warm up to normal operating temperature 2. if you’re using the defrost, it runs the A/C compressor and even though (as I recall) the Prius has an electrically driven compressor, it draws power from the traction battery so it’s further reducing the amount of EV energy available 3. the gas engine simply has to run more often in order to maintain temperature or else the catalysts would get too cold and it would have to drop back into open loop. Certifying that for emissions would be a nightmare. 4. the already mentioned difference in winter and summer gasoline. Winter gas is a bit more volatile to ensure ignition reliability in cold weather, and the trade-off is a bit less energy density. ---
**Author:** ![Bryan\_Ekers](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bryan_ekers/32/183_2.png) [@Bryan\_Ekers](https://boards.straightdope.com/u/Bryan_Ekers)\ **Post date:** [May 28, 2013, 12:49am UTC](https://boards.straightdope.com/t/does-the-use-of-a-radio-increase-a-cars-fuel-consumption/446309/37 "2013-05-28T00:49:28Z")
Listen to lots of dance music, help the car move along with steady pelvic thrusts. [Previous page](https://boards.straightdope.com/t/does-the-use-of-a-radio-increase-a-cars-fuel-consumption/446309.md?page=1)