Cold Weather Can Reduce Stated Hybrid Car Fuel Efficiency February 2005

Fuel economy is to hybrid owners as what horsepower is to sports car owners. They keep track of their mileage, brag about it and argue about it.

So it's no surprise that I heard from a lot of them after writing a story Feb. 3 that showed hybrids don't get the advertised mileage because activating the defroster keeps their engines from shutting down to save gasoline.

I asked those readers to keep track of their mileage for a week -- not that they needed urging. Some of them have been keeping track of their mileage since they bought their car. One reader -- Paul Valko of Oakland Township -- has a Web site with a chart showing the mileage at every fill-up since buying the car in December.

I tested the three hybrids -- the Ford Escape, Honda Accord and Toyota Prius -- with the climate control set to a mix of front defrost and heat to the footwells. That's the way I drive everything in the winter. I find that setting most comfortable.

All the hybrids come with built-in trip computers to calculate their fuel economy. I have found those to be inaccurate in a variety of cars and trucks, so I didn't use them to figure my fuel economy. I filled each vehicle with gasoline, drove it and calculated the mileage myself after refilling.

Automakers and hybrid owners say you must learn new driving habits to maximize the vehicles' fuel economy. They are happy to do that, because the people who build and buy hybrids strongly feel that using less fuel is a good thing for social, economic and environmental reasons.

I salute them for that, but the customers for the more mainstream hybrids now hitting the market may not share their conviction, so I consciously stuck to my regular driving style. My previous experience suggests that even under ideal weather conditions, this would lead to fuel economy at least 20 percent below the figures the automakers advertise.

As it turned out, the cold, but not unpredictable weather had a much more drastic effect on fuel economy. My mileage varied from 20.8 to 22.8 m.p.g.

The hybrid owners had different results when they drove:

The last three tanks of gas have averaged me 39.74 m.p.g. The car only has 2,300 miles on it and is still in its breaking-in period.

Everyone that I talk with online at a couple Web sites devoted to all things Prius tell me the cold Michigan winter and running the heat and defrosters all the time does reduce the fuel efficiency. It is no different in any other car, by the way, but since a hybrid's whole reason for existence is to lower emissions (the great mileage is actually a side effect) it's more noticeable. I am confident that the mileage will improve as spring temps arrive and the break-in period runs its course. Paul E. Poulin

Sterling Heights

We drove 316 miles this week, 90 percent on U.S.-23. I did a couple of quick trips too, under 4 miles. We averaged 46.3 m.p.g. When I drove I was making a point of ignoring the display, so I wasn't driving with conservation in mind. I did a couple of trips at 4 a.m., so it was pretty cold out. I bought one tank of gas. It was empty, the gas light was on, and I put 9.47 gallons of regular in it.

Diane Hallinen

Highland

This week I logged 757.7 miles, at 48.2 m.p.g. I enjoy driving my Prius. Like any piece of equipment, it helps if you learn how to use it effectively.

Michael Gaal

Fenton

Over the last week, I drove 404.5 miles and purchased 9.623 gallons of gas at $1.899 a gallon. That works out to be 42.03 m.p.g., although the readout on my car put it at 44.6 m.p.g. My car is a 2004 Honda Civic Hybrid. I am incredibly satisfied with my mileage, and I absolutely love my car.

Carly Siskind

Farmington Hills

I'm a former Detroiter living in St Louis and I actually flew up to Roy O'Brien Ford last November to buy the Escape Hybrid and drive it home. I had been waiting for a very long time, and I have not been disappointed.

I can tell you that the difference in m.p.g. achieved from when I first started driving it is striking. I, too, was getting around 23.3 - 23.5 until around 1,700 miles. The mileage shot up (with no difference in my lead-foot driving habit) to around 27 to 27.5.

SOURCE: Detroit Free Press

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