urusai

Hey all,

I recently acquired a 2003 V6 Tacoma and there's been something thats been on my mind for a while. As the title suggests, it has to do with air conditioning and fuel consumption.

When I acquired my first car (a 1993 Camry) my brother told me that I should not use the air conditioning as gas consumption goes up significantly. Now this I can vouch for as I would only get say 200 miles (on a full tank) on the odometer with the air conditioning on before the light would appear. However, when I rolled down the windows on a full tank I would get about 240-260 miles depending on my driving habits.

Here are a few things to consider.

One, my car was built in 1993 when the air conditioning systems used freon. HOWEVER, my air conditioner broke in the time the car was in my posession and I took it in to the stealer to get it retrofitted with the non-freon system. My gas mileage had been about the same.

Second, I live in Hawaii and most driving around here is done city-style with a LOT of stop and go, which would explain my poor mileage per gallon.

Then, just a day or two ago I was having another conversation with my brother and he told me that when he drives with his AC on he doesn't notice a difference in mileage, so I might as well use it. I figure I'd try it out but only when my tank goes empty (I have about 3/4th tank left.) Also he said that air conditioners these days are made to be much more efficient, though I really don't think he knows what he's talking about.

Can anyone verify this?

phong

fact.

The A/C compressor requires power. Power that is supplied through a belt that is directly attached to the crank pulley on your engine. When it is on, it puts an added load on your engine, which is why you see the RPM's increase when your A/C is on. Not only will you burn more gas, but you will have less available power which you can notice through more sluggish acceleration.

EDGE

On newer vehicles you will not notice a big change in gas mileage.

My 2000 Pathfinder got excellent gas mileage but if I went into the city and let it idle for 2-4 hours with the heat on verse idling 2-4 hours with the AC on compared to parking it and leaving it before I left the city their was no real difference in gas mileage if I drove the same way.

My friends 95 Chevy Pick up would drink half a tank with the AC on at idle in 2 hours, at least I could drive 100 miles and leave the AC on for 2-4 hours

Basically any new car I have driven the AC does not make a big dent in gas, with my Pathfinders and this 4Runner and the Lexus among other new cars the RPM does not even move when you turn the AC on.

Just my experience.

Hawaiian4R

Aloha urusai,
I lose a mile or two per gallon with the a/c on. Good thing I run it only when the wife is riding with me.

snappy

sup,

As a fact, it will draw some amount of power from the system -- it's a belt driven accessory so you can count on it to draw a bit of "power" from the system.

I say, if you're gonna be driving, might as well enjoy the ride. The best way I've found to conserve gas is to take the bus. I bought the car to enjoy, so why not run the AC?

I'm not advocating throwing money away, but if anyone is ultraconcerned about economy this V6 is the wrong vehicle to choose..

I hear that the new 4s will come with a hybrid gas-electric like the prius. elec to power the car @ speeds <15 mph (stop and go aloha morning traffic on H1), shifting over to gas for speeds over that, w/ BOTH powering things up in emergency accel/ full throttle situations.

butnut

Wow, howzit to urusai and Hawaiin 4R. Nice to see other locals here! Since getting my Runner in '99, I have never turned the AC off. My first vehicle with AC so I'm gonna use the heck out of it...especially here. Aloha.

Victor

In city you will use more gas with the A/C. If on the highway it actually uses less gas to have the A/C on then the windows open (wind drag). That said - I can open my sunroof and roll down the back window a couple of inches and I feel a noticable difference. Roll up the back window a couple of times while the windows are open - you can hear the wind drag disappear when the back window is down. So....A/C on the highway when its hot outside and if you live in the desert like I do - A/C on the street and crappy gas mileage.

Robinhood150

I just wanted to throw this out there: Everything that uses energy will eat into the mileage, even daytime running lights, your cigarette lighter and LEDs. It doesn't have to be belt driven. However, whether it's noticable is another story, most of these things are insignificant.

I've heard that newer ACs don't use as much energy, but I can't imagine much has changed in refridgerator technology. It might depend on the engine too.

Your best bet is to track your mileage for 3 tankfuls with your AC on, then 3 tankfuls with your AC off. I think that would be the only way to tell.

Steve

AJatx

The refridgerant used in the older vehicles are hands down more efficient at drawing out heat from a car. The compressor, dryer, and heat exchanger are another story.

The compressors are more efficient today (to make up for the loss in the refridgerant -- save our earth stuff) and it could net a small impact on gas mileage for city driving.

Highway driving is another story due to the different conditions (drag coefficient, etc).

J