After your home, your car is likely the second-biggest energy (and money) user in your everyday life.

Car Efficiency Basics

Keeping your car in good working order not only saves you money but makes your car less likely to break down. To maintain your car:

• Reduce drag: Close open windows and remove roof-top carriers unless you’re actually using them. This reduces drag, or wind resistance, when you’re driving, improving your car’s fuel economy.
• Fill tires: Keeping tires filled to their proper levels will reduce tire drag and can result in about 3% better fuel efficiency. Check your car’s manual to make sure that you’re filling tires to the appropriate level. Remem-ber that in cold weather, air contracts, and in warm weather, air expands, so regular checks of your tires will alert you to seasonal changes in tire pressure.
• Avoid oversize or performance tires: Oversize tires and performance tires with wider treads create more drag, reducing your car’s fuel efficiency.
• Practice regular maintenance: Ask your mechanic about your spark plugs—newer plugs will help your car run more efficiently. Regular oil changes also help your engine run at peak performance levels. Replacing a clogged air filtercan improve fuel economy by up to 10%. Also, make sure to use the grade of motor oil that’s recommended by your car’s manufacturer, as the wrong oil can reduce your engine’s efficiency.
• Use cruise control: Using cruise control (keeping the speed of your car constant) on the highway will result in gas savings. Variations in speed reduce fuel economy, so even when driving around town, try to brake and speed up evenly and smoothly. Short stops and quick starts wear on your car’s moving parts and waste fuel.
• Don’t idle: If you’re going to be stopped and waiting for more than 30 seconds or so, turn the engine off. After 10 seconds of idling, your car has already used more fuel than it would if you had turned off the car and turned it back on again. If you live in a cold climate, warming your car up for about 30 seconds in the winter is sufficient. Many people idle their cars for 5–10 minutes before driving in the winter, but modern cars don’t need this kind of warmup.

Fuel Options

Buying a new car with good fuel economy will save you an enormous amount in fuel costs over the life of the car. With gasoline prices rising and concerns about global warming at the forefront, alternative fuels have gained prominence, but you can still save money by making a wise choice with a traditional gasoline-powered car.

Gasoline

You don’t need to buy a hybrid or run your car on biodiesel to save money and reduce carbon dioxide emissions. Often, nonhybrid vehicles are just as fuel-efficient as comparable hybrid vehicles. In general, buy the smallest car that you can live with and keep an eye on the fuel economy numbers, which can vary within the same model, depending on special features (such as extra engine cylinders, sport packages, and four-wheel or all-wheel drive).

Hybrids

Hybrid cars run on standard gasoline the majority of the time but use an internal battery to collect energy from braking. They then use that stored energy to provide extra power to the car, thereby reducing the amount of gasoline used. Several automakers have hybrid models, from SUVs to luxury sedans. Honda, Chevrolet, Lexus, Ford, Toyota, and Mercury all have hybrid vehicles that get better fuel economy than standard models of the same car.

Ethanol

Ethanol is a corn- or other starch-based gasoline additive that most drivers already use (in amounts up to 10%) in gas-burning cars. There are also flex-fuel cars that burn ethanol in amounts greater than 10%. E85 is a 15% gasoline, 85% ethanol mixture that runs about 30–60 cents cheaper per gallon. However, cars that burn this fuel must have special engines; E85 cannot be used in a regular gasoline-powered car.

Biodiesel

Biodiesel is a clean-burning type of fuel that’s made from animal fats and vegetable oils. Most biodiesel comes from soybean oil, but it can also be obtained through waste vegetable oil (WVO)—most commonly obtained from restaurant fry vats (resulting in exhaust that smells like French fries)—and even algae, an up-and-coming source.

Biodiesel is nontoxic and biodegradable, produces few greenhouse gases, and comes from renewable sources. Pure biodiesel must meet the strict health standards of the 1990 Clean Air Act. It also must be registered with the EPA in order to be sold and used legally in the United States (anything marketed as straight vegetable oil, or SVO, does not make the cut, as it can damage the car’s engine over time). You can get this type of fuel from gas stations around the country—check biodiesel.org to find a station near you.