Why the hell is the A/C in my car using so much gas? - General

So, I have a 2005 Chevrolet Malibu Classic, and the a/c in it eats up gas like no other car i've seen in my entire life. I did 2 runs with it, full tank of gas, one run with the A/C on (Because it's blisteringly hot here EVERY DAY), and one run with the windows down. From full to empty, on the A/C run, yielded 265 miles. From full to empty, windows down, the car made it 370 miles. So, the A/C is using up over 100 miles worth of gas per tank. How the hell is this possible?

do you literally have like an industrial A/C inside your car or something

Nope, just the stock A/C that came with the car.

Did you drive to the same places? highway vs city is dramatically different

I drive a hell of a lot, and the average mileage per tank on this thing this summer has been around 260-280 while using the A/C.

The engine is running the A/C pump? making it work a little harder when you run the A/C.

that doesn't sound right at all were the driving conditions different for both times?

i'm a fridge mechanic, thats really quite normal; car air-conditioners usually add a 2kw strain on an engine which usually have a 400watt load (alternator etc). i do alot of work on off engine drive fridge systems and i find diesels to be better on the fuel consumption

When everything on the AC is working, ranging from the compressor to the climate control interface, it can use UP TO 60 amps if it's dual zone. Which when doing some math, would end up at around one horsepower. That shouldn't put any strain on the gas mileage. [editline]12th July 2011[/editline] I mean, my grandma puts more strain on the engine than the AC. Well, probably cause she's fat. But still.

60 amps? more like 15 tops, and even so that's electrical. that's the alternators problem.

[QUOTE=Exille;30993952]The engine is running the A/C pump? making it work a little harder when you run the A/C.[/QUOTE] AC pump? Really dude? [editline]12th July 2011[/editline] Also, most AC compressors are belt driven, and smaller motors can experience a performance hit with the AC on. This is INCREDIBLY noticeable in Miatas, to the point that it can be dangerous. It literally feels like I lose 50 horse when I turn the AC on. It's the same way in my girlfriend's Honda Fit, turn on the AC and it feels like a Prius. If your car is one of the 4cyl Malibu's, you're looking at 140 horse, maybe 110 at the wheels. The AC could make a noticeable impact.

What the hell is air conditioning?

[QUOTE=scottybev;31069140]60 amps? more like 15 tops, and even so that's electrical. that's the alternators problem.[/QUOTE] Which is why I said up to. That's under extreme conditions, like the middle of death valley in the dead of summer at the hottest point in the day in a black mini-van with a panoramic sunroof and the dual zone AC on. The point is AC should never cause your fuel economy to drastically drop. Something else is going on here. 15 amps is even easier for an Engine output. It relates to .02 horsepower (non-metric).

When I turn my steering wheel from all the way to the left and crank it all the way to the right, I can hear the engine in my 'Nasty struggle a little. Nothing horrible, just suckin up what little horses there are. :v:

[QUOTE=Second-gear-of-mgear;31074085]Which is why I said up to. That's under extreme conditions, like the middle of death valley in the dead of summer at the hottest point in the day in a black mini-van with a panoramic sunroof and the dual zone AC on. The point is AC should never cause your fuel economy to drastically drop. Something else is going on here. 15 amps is even easier for an Engine output. It relates to .02 horsepower (non-metric).[/QUOTE] that only relates to electric motors though, none of those things have anything to do with the fuel anyway, the engine only runs the compressor

Yes, Really. Dude. way to be a nazi. [QUOTE=Boom_Hedshot;31069451]AC pump? Really dude? [editline]12th July 2011[/editline] Also, most AC compressors are belt driven, and smaller motors can experience a performance hit with the AC on. This is INCREDIBLY noticeable in Miatas, to the point that it can be dangerous. It literally feels like I lose 50 horse when I turn the AC on. It's the same way in my girlfriend's Honda Fit, turn on the AC and it feels like a Prius. If your car is one of the 4cyl Malibu's, you're looking at 140 horse, maybe 110 at the wheels. The AC could make a noticeable impact.[/QUOTE]

Compressors take a lot of force to run. It's essentially a belt-driven mini engine on your engine, in a simple way to put it, and forcing it to run takes a lot of energy.