Air Conditioning and MPG

[coxcj]

Hey all. Now that we're well into the hot months, I'm curious about something. I've been losing roughly 2mpg on tanks of gas where I've been using the AC.

Has anyone else noticed the drop in mpg? Has it been more/less severe for you?

[biggie]

Haven't driven the car without AC yet. Did average over 32 mpg on 550 mile trip Saturday, AC all the way.

[br4dysays]

i live in fla and got my car in MAY. so there hasnt been much driving without the A/C lol.

but id say the best ive AVG MPG is like 33. but i havent done any strictly hwy trips or the like, all mixed driving.

winter will be great

[kc5f]

When I lived in Tulsa I had a car with a black vinyl interior and no A/C, so I got somewhat used to hot weather. I don't turn on the A/C now until it's 92 or 93, and it's just hit that in the mountains this week for the first time this year. However, at work (1200' lower) it's often that high, so I tend to use the A/C when I leave work, for about 2/3 of the commute home.

I've been surprised, however, to notice very little difference from tank to tank when I think I've used the A/C more than "normal". For the last 9000 miles each tank has been between 33 and 35.5 mpg. The biggest change was before that, when they changed from winter to summer gas formulation. There was an immediate jump from 30-32 mpg to the current figures. So if your gas changes formulation in the winter, then no, the winter won't be something to look forward to...

[srellim234]

Like others, we just bought the car this summer, the temp has been mid-90s to low-100s. Add two trips to 110*+ Palm Desert and the a/c has been on since we bought the car. If it ever cools down we'll let you know if the mileage is much better without a/c.

From past experience and reading, however, one used to expect a 10% drop in mileage while running the a/c. Now that cars are being designed so much more aerodynamically, the discrepancy is probably less because open windows and sunroofs create more drag by disrupting airflow. I still would expect the a/c to hurt mpg a little bit.

[srellim234]

Just filled up the gas tank and I continue to be more disappointed in the mpg the more I drive the car. I get 27+ highway mpg out of a big 2002 Buick Rendezvous with an automatic, 6 cylinder and seats 7. Best tank of the first 5 on the Versa was 30.0, and the car is averaging 27.4 overall.

It's obvious that this engine/transmission was designed to maximize mpg under the federal testing guidelines, not the speeds/conditions existing in the real world.

Nice car, but this is NOT the commuter car we were looking for and told this one was.

[coxcj]

That's interesting. I've had mine for 2 months, and all I do is commuting (35 miles one way). The best tank I had was 32.8mpg and the worst was 28.7mpg. The bad tanks have always been with the hotter days when the air is on. I know that I also have a problem with mileage whenever my wife drives the car because she likes to pound the gas pedal and have the engine constantly reving over 4k. When I drive it, I keep the rpm between 2k & 3k and usually it does fairly well (for Chicagoland rush hour driving, anyway).

[srellim234]

My biggest diappointment is with the American consumer and the auto companies. I understand supply/demand but there isn't an entry level priced commuter car that can compete with an entry level commuter car from the mid-90s in mpg today.

Over the years I have almost always gotten better gas mileage than EPA estimates. My averages at least have always been in the acceptable range. We fully expected to be getting at least 30 out of this car since it was rated 30 city, 36 hwy.

The fact that the car averages only 27.9 combined in real world figures city/hwy is poor. I'm guessing at this point my figures are even lower because it's been hot with the a/c on every day since we bought it.

My bad decision for not doing additional research into the real world figures before purchase. It is a very good car, just not filling the needs of what I was looking for. I was looking for a car that would be pulling 32-35 average and made the false assumption that since the 30/36 sticker was in the range of other cars they would all get about the same mileage (less than sticker, but all similar) in real world driving. Now I see other entry level cars outperforming the Versa in actual mpg reported by owners (Fit 31.8, Yaris 35.3, Versa 27.9). Even some larger cars are outperforming it.

Like I said, a very good car but it doesn't fill the need I was trying to fill.

[coxcj]

The fact that the car averages only 27.9 combined in real world figures city/hwy is poor. I'm guessing at this point my figures are even lower because it's been hot with the a/c on every day since we bought it.

My bad decision for not doing additional research into the real world figures before purchase. It is a very good car, just not filling the needs of what I was looking for. I was looking for a car that would be pulling 32-35 average and made the false assumption that since the 30/36 sticker was in the range of other cars they would all get about the same mileage (less than sticker, but all similar) in real world driving. Now I see other entry level cars outperforming the Versa in actual mpg reported by owners (Fit 31.8, Yaris 35.3, Versa 27.9). Even some larger cars are outperforming it.

I'm really sorry you feel that way. Before this car, I had a 97 Jetta. I averaged 31mpg with it, and I decided from the start that I would not get anything less than that. I expected more from the Versa than I've been getting, but it's still not at the disappointing level. My average has been right around the low end of the estimates, which is exected, now that I know more about how the EPA figured out the estimates.

I do have a question, though. How do you drive your car? Do you have hard accelleration/decelleration? The reason I ask is because I think this car just needs a lighter touch to perform better. Looking around the forum, I've seen a lot of people that have gotten into the 30's for their averages.

Something to check out: http://www.fueleconomy.gov

This was very helpful for me to see what the more "real world" estimates are.

[srellim234]

I have the lightest foot of anyone I know. I often get dirty looks from people who think I'm too slow accelerating. My wife included.

I'll let some of my real world figures do the talking. The EPA rating on my 2002 Renezvous was (non-adjusted) 19 city, 26 hwy. I've averaged over 22 since I got the car, including averaging over 29 mpg on a 5,000 mile round trip to visit our son in Florida, including some city driving around Oklahoma City, Jackson, MS, Panama City Beach and San Antonio.

I've rented two Toyota Prius, one in Chicago winter (3 weeks 61 mpg.) and one in Ft. Lauderdale summer (5 weeks 63 mpg.) I averaged 34.1 over 6 years with a 1994 Honda Civic with automatic transmission and a/c (it was black, so the a/c ran all the time in that car, too). I could even count on every Buick Century I rented over the years to give me 29-30 mpg highway with the a/c running.

The 27.9 for the CVT Versa and the figures cited for the other cars are also from the same government website you refer to. I could live with 30+ mpg. I'm hoping to get a ScangaugeII on this thing soon so I can find out why the high mpg tactics that have always worked in the past don't work on this car.

I suspect the CVT has a lot to do with it. This transmission puts drag on the car at all times; in other cars I could always coast at highway speeds with no pressure on the gas pedal.

[coxcj]

I wish you the best of luck. I'm thinking of getting the Scan Gauge as well. If I think of anything else that might be able to help, I'll let you know.

[srellim234]

Thanks.