Starting Your Car/Computer consumes more energy? Guess this is two separate questions:
(1) Does turning on your computer (starting it up) consume more energy than if it were just %26#039;on%26#039;, as yours is now? I%26#039;m asking because I%26#039;m wondering how much more energy is consumed - if I%26#039;m going to be away from my computer for 10mins, is it worth it to turn it off and on again in 10 mins, or is this more costly than just leaving it on? Ignore the energy-saving-standby modes.

Similarly,
(2) Does starting your car consume a heavy amount of gas, compared to leaving it idle in Park? For instance, would I save more gas leaving it in idle for five minutes, or should I turn it off, and then back on again - is the startup costly?

Ignore environmental concerns, just look at consumption cost for startup here. I%26#039;m looking for a scientific answer, thanks

Best Answer

No surge of any appreciable size.

On the computer -- don%26#039;t take my word for it. Put a meter on the line and watch it. Amazon sells the %26quot;Kill-a-Watt%26quot; meter for under $30 that just plugs right in. Computers don%26#039;t surge POWER, they surge TIME. They take awhile to start up. There%26#039;s the power it takes to run it for that time.

On the car -- just look at the hypermilers. They say %26quot;shut your engine off at a red light%26quot;. Why would they say that if it took a ton of fuel to restart? Scientifically, IF it used a bunch of fuel, where would that go? It has to take in oxygen to burn that fuel or it would become unburned hydrocarbons (engines must be designed not to under modern emissions law). So where is it ingesting this huge amount of oxygen to burn this burst of fuel? It%26#039;s not.

Now a coldstart of an engine can be more wasteful, it has to throw the mixture rich to get a coldstart. But a) that%26#039;s much better than it was due to technical changes forced by smog laws, and b) that%26#039;s not really relevant to your question, since you%26#039;re talking about warmstarts. Engines will keep their heat for an hour or more.

Asker's Rating:

Thanks

Other Answers (2)

• Yes, there is a power surge through the computer and car that requires an initial and powerful boost of energy to start the engine and computer.
  
  There are two ways to approach this. If you are looking to realize the full life of your computer, don%26#039;t turn it off and on frequently because the power surge required to turn it on is damaging over the long term.
  
  The same goes for a car. A lot of parts go from sitting idle to moving quickly and abruptly. The more frequently you start the vehicle, the more damage you are doing over the long term.
  
  If you%26#039;re trying to save gas/power or just energy in general. Use the Energy Saving standby modes suggested by the computer. As for the car, don%26#039;t accelerate too quickly as you use the most gas when accelerating quickly.
• 1) Starting a computer does not take more than running it, although it probably takes more than it would take in sleep more or standby or power saving or whatever.
  
  2) Stopping and starting a car uses less fuel than letting it idle for a couple minutes. I learned this during the Arab Oil embargo of the 1970s waiting in lines at gas stations. Some people stopped their engines and pushed their car up one car length every time the line moved, others just idled the whole time and others started and stopped the engine each time they moved up. The TV said that idling a couple minutes used as much gas as starting it. It is worth noting that a Prius will start and stop its gasoline engine frequently, as needed. The driver has no say in the matter, the car%26#039;s computer decides. This saves fuel.