Turned on a/c, dropped 6 mpg

[jorton]

99 Mercury Tracer a/t, 190,000 miles
I started using the air conditioning and fuel economy has dropped from 31 to 25 mpg. The car was LOW on power before so this mpg drop is probably normal. Soon I'll get the injectors serviced. In my mind I'm sure that will restore some power and improve fuel economy.

I started using the a/c about the same time I changed oil from 10w-40 to 10w30.

 

[mpvue]

I used to have a saturn SC1 (85hp!) that would slow down on the hwy when the A/C was turned on; couldn't maintain 60mph! barely got 25mpg, what a slug that car was (before I swapped in the twin cam!)

 

[Johnny]

Roll the windows down and turn the A/C off. If you get hot, go down to the River Walk and have a cold one at one of the fine establishments.

 

[sdan27]

I had a buddy that had a TDI that said he dropped 10 mpg in the summer with the A/C on.

 

[CivicFan]

In our A6, the mpg drops from around 22 to around 19 with the A/C on. For a 300 HP engine it is a little surprising.

 

[adamrc]

I have a 2001 VW Golf TDI and with the A/C running, I only notice about a 1-2 MPG drop. My father and brother have a TDI as well and notice about the same. I don't notice any power loss either in the diesel due to all the low end torque.

 

[sparkplug]

My Jeep gets 15-17 mpg no matter what I do. I'll take my A/C!

 

[jstutz]

my mercury mystique with the 2.0 runs about 29mpg, this summer with the ac blasting everywhere we go, fuel mileage has dropped as low as 26.5 but avg is still around 27. There is definitely a reduction in power but fuel mileage just dropped a little. Granted we do a lot of highway driving and it is mostly flat. Im sure the results vary based on driving styles and conditions.

 

[ryansride2017]

That's one mythbusters show I never agreed with. Their conclusions were that running above 45-50 mph, wind resistance with the windows open consumes more gasoline than using the air conditioner. I just don't see it in the real world.

 

[Nick R]

Originally Posted By: ryansride2017
That's one mythbusters show I never agreed with. Their conclusions were that running above 45-50 mph, wind resistance with the windows open consumes more gasoline than using the air conditioner. I just don't see it in the real world.


You don't? Think how much time and money auto engineers take to make cars as aerodynamic as possible. Very tiny differences in shape and styling can make a huge impact. You don't think a couple gaping, 1 1/2' x 1 1/2' gaps might make more difference than a small compressor running off the belt?


My car is pretty slow with the A/C on, but I hope the mileage doesn't drop too much (considering I only average about 24mpg per tank usually)

 

[jstutz]

whats weird is that with my blazer and suburban, i cant tell any differences in fuel mileage with it on or off. But with the mercury i can definitely tell.

 

[mechtech2]

Smaller engines drop more felt HP and % gas mileage with the AC on than big powerful ones.
6 MPG is a lot, but not unreasonable or unaccountable.
If the AC is on sometimes, we get less of a hit. With it on almost all the time, we will feel it.

 

[mpvue]

Originally Posted By: ryansride2017
That's one mythbusters show I never agreed with. Their conclusions were that running above 45-50 mph, wind resistance with the windows open consumes more gasoline than using the air conditioner. I just don't see it in the real world.

sooo, 2 guys that used the scientific method to come to a conclusion with data to back up their findings, you have decided not to agree with.
okay, makes perfect sense.

 

[DreamerGT]

Thats true, I had a 96' dodge neon and I would have to turn the a/c off just to pull out it to traffic. I lost alot of power, but in the stang and vic I can hardly feel a difference.

 

[sciphi]

I can't feel a difference in my 99 LeSabre. The mileage takes a 2-4 mpg hit, as verified by the ScanGaugeII in the car. Ahh, it's nice at times to have a big ol' V6.

 

[Hermann]

I am about 2 MPG down now that the A/C is on all the time. But I'll take 24 MPG all the time in a truck.

Here's a link to my Fuely.com

http://www.fuelly.com/driver/frugalfueler/tacoma

 

[antonmnster]

I sometimes end up driving around in my work truck with the ac on and the windows down - fewer headaches. The 04 F350 weighs in at about 9500# so the compressor draw changes the MPG from maybe 6.8 to 6.7.

 

[oggb]

My around-town MPG with the A/C on is 2-3 mpg worse.

On the highway I can drive 80-85 with the a/c on and get 29. I can drive 65 with the AC off and the windows up and get 29. I can eat green eggs and ham and get 29.

Weird, I think.

 

[Eddie]

I loose 1.6 MPG when I run the AC 100%. I keep fuel records and my results based on ~ 3,000 miles. Mazda CX7 Without AC I normally get 21.7 mpg averages.

 

[nfs480]

I average about 1 mpg worse in my '89 Accord with A/C on full blast.