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Which is worse, leaving the ac on for a few hours or having a fan on all night? Want to know what is better for the environment, energy bill, in general

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1 month ago

yes i literally mean ac for about 3-4 hours a night or a small 10 inch fan all night

Best Answer - Chosen by Voters

Good question...
The ac will consume more electricity in a few hours than a fan will all night. Look at the back of your fan, there should be a wattage rating on it. If it is rated in horsepower rather than watts convert using 746w=1hp
Your best bet for efficiency would be a ceiling fan they are usually about 1/10 hp or +/-75w
Look at your power bill to determine your cost per kwh (kilowatthour) or 1000 watts one hour or 100 watts ten hours, you get my drift.

Your ac will not only run it%26#039;s fan, but compressor for those couple of hours and compressor load is quite high compared to fan load. Depending on the heat and humidity you compressor might be running at full load, probably at least 15 amps. The formula for conversion is W = V * A.
120v*15 amps = 1.8 kilowatts. If your electricity costs .25 per kwh your cost for compressor is $.45 per hour so three hours would be $1.35 add about $.50 to this for the air conditioner fan and your cost is $1.85 per day.
Ten hours of a floor fan on medium at 375 watts would be 3.75 kw * .25 would be about $.94

AC $1.85
Fan $.94

These are rough numbers, you would have to rate your appliances yourself and factor in your energy costs, but it should give you a good idea of where you%26#039;re at. 40% 2 Votes

Other Answers (12)

  • Not sure why nobody is answering the question. You didn%26#039;t ask about leaving the A/C on all night.

    The answer is that (under average circumstances) leaving the A/C on for a few hours is worse. Even a big box fan uses less than a quarter of the energy of an average window air conditioner, so unless your %26quot;few hours%26quot; is only a quarter of the night, the A/C loses the battle. 20% 1 Vote
  • What is wrong with all the previous answerers? They did not read your question since they%26#039;re all saying %26quot;ac on all night%26quot; and that was not one of your options. I%26#039;d imagine the a/c for a few hours is worse because it uses so much more power than a fan. 20% 1 Vote
  • We need to know if this is a whole-house fan, we need to know the wattage of the fan, we need to know the type of AC unit and the wattage. It would help to know the outside temp and inside and the thermostat setting 0% 0 Votes
  • I run my A/C whenever it is over 70 degrees outside and I run two fans all year long every night whether the A/C is on or not. That%26#039;s what makes me comfortable. I save by hardly ever turning on a light except the room I%26#039;m in. 0% 0 Votes
  • AC all night is absolutely much harsher on the bill than the fan, seeing as it is much more powerful. 0% 0 Votes
  • Its fan on all night!!

    Not ac all night he said ac for a few hours gosh!! 0% 0 Votes
  • definetley ac on for a few hours because of how powerful it is. and to everybody who said ac all night CANT READ! lol 0% 0 Votes
  • The ac all night. 0% 0 Votes
  • try one than the other, then check your electric bill. 0% 0 Votes
  • ac at night is better that peak load time.
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