October may have been the warmest on record in Portland, but most Mainers know that even climate change can’t keep winter at bay for long. One day soon, inevitably, the cold season will slap us in the face.

Even in winter, when you’re heating your home and turning the lights on early, it’s possible to shrink your climate change footprint. One way to do so? Get your car ready for the ice and snow. Maintenance tips and other ideas abound that will not only keep your car running smoothly in the bitter cold, but ease its impact on the planet as well.

The fuel economy of cars drops in winter for a host of reasons. Engines run richer in dense cold air, which means more fuel runs through them, leading to worse mileage. Snow and slush on the roads, and the aerodynamics of the car, create drag.

We asked several experts for advice on how to prepare a car for eco-conscious winter driving. Here’s what they had to say:

DEFLATEGATE

Most drivers know it’s important to keep tires properly inflated, but in Maine – and in winter – that is particularly true. As the temperature drops, so does tire pressure.

“It’s one of the major causes of loss in fuel economy,” said Travis Ritchie, education outreach coordinator for Paris Autobarn, an eco-friendly auto repair shop in South Paris. “Pressure is dependent on temperature, so the pressure in that tire constantly fluctuates with temperature. In Maine, we have such a wide spread of temperature, we experience (tire pressure fluctuations) on a regular basis.”

Nearly all modern-day vehicles have a tire pressure monitoring system on board, Ritchie says, but some do not alert the driver until the pressure is substantially low.

If a tire’s optimal pressure is 35 pounds per square inch, but in winter it underinflates to 28 psi, the tire will have an increased rolling resistance of 12.5 percent, Ritchie explained; that means the engine has to work harder to move the vehicle down the road. It also means the car uses more gas – and contributes more greenhouse gases – than it would in the middle of July.

Proper tire pressure can improve gas mileage by 3.3 percent or 10 cents a gallon, according to the Car Care Council, a nonprofit group based in Bethesda, Maryland.

“It sounds really basic, but it’s something most people don’t tend to,” said Sarah Cushman, a sustainable transportation consultant and former auto mechanic. “You want to check that once a month.”

Don’t forget to check the spare too.

SEASONALS OR STUDDED?

Winter tires are, generally, safer than summer seasonal tires or all-weather tires, our experts say. But they do have more rolling resistance, which means fuel economy goes down. Consider using the most efficient seasonal tires during the warmer months to counter the impact of switching to winter tires (studded or not) during the cold months.

SNOW AND ICE, NOT SO NICE

Snow and ice buildup on the road, and on your car, impairs aerodynamics – and therefore damages fuel economy.

The amount of snow and ice on the road is up to Mother Nature and the local public works department. But don’t be one of those annoying people who drives down the road with a foot of ice and snow on the roof, endangering not only the environment but the folks driving behind them when it flies off in big chunks at 65 mph.

Here’s a tip from Ritchie: Make it easier to remove snow from your car with regular cleaning and waxing. A waxed finish will shed most snow, he said, or at least require less effort to remove it.

“If you have a buildup of dirt and grit on the outside of the car and you’re traveling at highway speeds,” Ritchie said, “there is a measurable effect of wind resistance. Technically, in the long run, a cleaner car is more efficient than a dirty one.”

REMOVE THE ROOF RACK

That roof rack that helped you stay fit in summer by holding a bike or canoe is a drag in winter – literally.

“You’re not going to be canoeing and kayaking any more,” said Dylan Voorhees, climate and clean energy project director at the Natural Resources Council of Maine. “Take it off because it’s going to be reducing your fuel efficiency.”

TAKE A LOAD OFF

Admit it. You’re one of those people who load the trunk with bags of sand or salt, or anything heavy, to provide a little more traction on snow-covered roads. Ask yourself: Do you really need all that extra weight to be safe, or is it more like a security blanket?

“Certainly the more weight that’s in your car, the less efficient that’s going to be,” Voorhees said. “That’s a very direct relationship, so unneeded weight in your trunk, or wherever, should go.”

Consider this a good excuse to finally clean out your car.

TURN DOWN THE HEAT?

It’s a classic question of short-term comfort versus long-term gain: It’s 10 below outside. Should you be seduced by the remote starter and retreat to the sofa for another morning cup of coffee while your car warms up without you, fully aware that idling is an environmental sin? Should you jump in the car and blast the heater, praying it won’t be long before you can’t see your breath anymore? Or should you turn on a blessed seat warmer and be comforted by a toasty bum while you wait for the rest of the car’s interior to heat up?

With an internal combustion engine, the bottom line is that getting warm takes more gas. The question is, how much more gas?

Blasting the heat as soon as you get in the car won’t do any harm, our experts say, but it won’t do you much good. You’ll still sit there shivering for a while. That’s because the heat that warms the car up on a winter morning is a waste product of the engine’s combustion. The car won’t send that extra heat out into the cabin until the engine is warm and purring.

“Your car will probably warm up faster if you keep your heat off until the engine gets warm,” said Charles Ayers, president of the Coordinating Committee for Auto Repair, a nonprofit group that teaches green practices to auto shops. “The heater core in vehicles operates much like a small radiator, which is designed to pull heat away from the engine once it reaches normal operating temperature.”

But idling is not good.

Ritchie said research has shown that combustion byproducts and moisture from the exhaust build up while a car idles and can damage the vehicle in the long term. Idling also releases a lot of carbon dioxide and combustion gases, he said.

Why do we like to idle our cars? Cushman says it’s an artifact of the “days of the carburetor,” when driving a car without first warming it up was bad for the engine. “We still live with that mythology of ‘you’ve got to let the car warm up,’ ” she said. “But that’s not the case today with fuel injection, etc. So it’s a big no-no to start it remotely or idle it until it’s warm.”

Most manufacturers recommend driving off gently about 30 seconds after starting the engine, according to the U.S. Department of Energy. The engine will warm up faster, which will allow the heat to turn on sooner, in turn lowering fuel costs and reducing emissions.

What about those seat warmers – and the heating devices they are often bundled with that defrost the side mirrors and windshield wipers?

Our experts say go ahead and indulge, especially if it cuts back on idling by easing the discomfort from the cold.

CLEAR WINDOWS WITHOUT CHEMICALS

Scraping ice and snow off the windshield and windows can build biceps even Popeye would envy. But is there an easier way?

We’ve already established that letting the car idle until the defroster can do its work is not a good idea. Our experts also discourage the use of spray de-icers, except for the tiny ones carried on keychains that unfreeze the door locks. Ritchie cited one common spray de-icer that contains methanol, ethylene glycol and silicone and is flammable.

“It is harmful to get on your skin, if swallowed or inhaled,” Ritchie said. “Ethylene glycol is most famous for being in common antifreeze. It’s toxic to animals, and any ice or snow you spray with the product will retain a small amount. Of course, it is dosage of a toxin that is as important as the toxin itself, but it may build up if it is used in one specific area repeatedly.”

Ritchie added that, in the bigger picture, the amount of energy that goes into making the chemicals just for the convenience of scraping less by hand is “questionable.”

Ritchie, who drives an electric car, stumbled across something else that works. He uses Rain X, a product designed to repel rain from the windshield, to fight winter weather. When applied correctly, he said, the ice and snow will slide off the windshield “with much greater ease” and without added heat.

THINK AHEAD

A suggestion from the U.S. Department of Energy: Parking in a garage will increase the engine and cabin temperature you start with so the car will warm up faster. Also, combine trips so you drive less often with a cold engine. And carpool, when it’s practicable, admittedly a good all-season practice.

THE TANK IS HALF-FULL

Keep the fuel tank half-full in winter. Water condenses at colder temperatures, so it will help prevent condensation in the gas tank, which affects performance.

Pay attention to what goes into the tank as well. Find a retailer that sells certified Top-Tier detergent gasoline instead of lower-quality gasoline that leaves deposits on critical engine parts, reducing performance.

“Whenever possible, I try and fill up my vehicle using Top-Tier gasoline,” Ayers said. “Top-Tier gas has many benefits, including preventing carbon buildup within the engine.”

I’M A LITTLE RUSTY

Cars don’t rust out the way they used to, perhaps because manufacturers are using more rust-inhibiting materials in the factory. But plenty of Mainers still fear automotive rust and want to apply some kind of winter protection from ice-melting road chemicals to the underbody and suspension components of their cars. Undercoating products are usually oil-based and not very environmentally friendly.

At Paris Autobarn, the mechanics use Fluid Film, a lanolin-based product made from sheep’s wool. It costs $100-$150 for most cars.

LOSE THE LEAD FOOT

Driving more slowly is a tip that could be followed year-round, Voorhees admits, but it’s one that most Americans could stand to try. Slow down, take a deep breath, and think about all the money you’re saving not playing chicken with that pickup truck.

“Driving slower means more fuel efficiency,” Voorhees said. “We’re all rushing around in life seemingly a minute behind, but it is true that if you are driving slower you are saving fuel.”

Slowing down from 75 to 65 mph, he said, reduces gas consumption by about 15 percent. Each mile per hour driven over 60 is like paying an extra 15 cents per gallon.

A bonus: It is usually safer too.

TAKE CARE

The best thing to do to improve efficiency in winter is to keep the car in good shape and tuned up, our experts say. While many of the maintenance tips listed here are small things, they add up – and some of them cost nothing.

“If your tires are low and you haven’t had a new fuel filter in a while and you’ve got 100 extra pounds in the back, all of those things together you could be talking about 15 percent greater fuel efficiency,” Voorhees said. “That’s not nothing.”

GET READY TO RUMBLE

When it comes to clean winter driving, it really is no contest, our experts say. All-electric cars or plug-in hybrids beat gasoline-powered cars, hands down – especially here in Maine.

That’s because the internal combustion engine is really inefficient, and the electricity mix in New England contains lots of renewables and hardly any coal, Voorhees said.

“Given where Maine’s electricity comes from, driving electric miles is vastly cleaner per mile than any combustion car out there, even a really efficient combustion car,” he said.

The biggest downside to driving an electric car in winter is that the batteries lose performance as it gets colder outside, which reduces the range of the car and increases charging times. Voorhees said the mileage reduction in winter is roughly 20 to 25 percent, which may or may not be a big deal, depending on the car. A Chevy Volt, for example, has just 50 miles of all-electric range, so a cut of 20 to 25 percent is substantial.

“If your car is going 250 miles on a charge like a Bolt or a Tesla, then losing 20 percent probably doesn’t change your day very much,” Voorhees said. “So the winter performance issues will be decreasing with the total number of miles an electric car is going. It gets better and better every year.”

When it comes to all-wheel drive capabilities, which a lot of Mainers rely on in winter, electric options are limited: Tesla is the only manufacturer that offers it right now, in three models, Ritchie said.

But electric cars have other wintertime advantages over gas-powered cars. Compared to traditional front-wheel drive vehicles, electric cars have good weight distribution for traction and handling because their battery packs are heavy and located low, Ritchie said. Most modern cars have traction control, he said, but since the computer in an electric vehicle can directly alter the speed of the motor, it works much faster.

And electric cars are easier to heat up without wasting energy. Many of them allow drivers to remotely start the car’s heater and defrost the windows, and still drive off with a full battery.

“If plugged into the grid, it’s likely that you’ll be using electricity from the source, not from the vehicle itself, to make the inside of your vehicle comfortable before getting into it to drive,” Ayers said.

Even without a remote start, if the heater is turned on right away it will heat the cabin faster since it doesn’t require the engine to warm up first.

Meredith Goad can be contacted at 791-6332 or at:

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