Energy is expensive, and yet it gets wasted all the time. For example, observe drivers on our mountainous roads. Many use their brakes going uphill, when it would have been sufficient to just step off the gas pedal and let gravity slow the car to the desired speed.

It’s a largely unknown fact that braking requires energy, because the vehicle has to burn more gas to come up to speed again. It’s one reason why auto clubs and law enforcement recommend a calm, steady driving style, with gentle use of the accelerator and brakes.

The wasted energy in braking is converted into heat and transmitted uselessly into the atmosphere. Fuel-efficient drivers keep a safe distance, looking ahead and easing off the accelerator early, requiring less brake action. The U.S. Dept. of Energy estimates that only 14 percent to 26 percent of fuel is used to actually move the car. The rest is consumed by items like tire resistance, engine friction, brakes and more (www.fueleconomy.gov/feg/atv.shtml).

Energy is also wasted in the home. Robert Eidson, a Gainesville energy efficiency consultant, says “there is no one silver bullet to energy conservation but the first place to look is the HVAC (heating and cooling) system. It accounts for half of the utility bill, it’s the biggest power consumer, and in most homes, also the most wasteful one. We find that usually 40 percent of the energy is wasted.”

This isn’t about reducing comfort or sitting in the dark. It’s about ensuring that the energy goes where it’s supposed to.

“Checking for air leaks at the unit and around ducts can reveal huge amounts of waste, especially when ducts run through crawl spaces and attics,” Eidson said. “Users can get ducts sealed by a professional. For the DIY person, using tape and duct sealant works well. Youtube has lots of how-to videos.”

Many home owners have reported a 30 percent to 50 percent drop in utility bills after eliminating air leaks, and getting the unit serviced. Buildup of dust in the coils of a heat pump or air conditioner is a power drain, and so is incorrect refrigerant pressure. Using pleated filters instead of the cheap, thin fiberglass type prevents dirt from building up in the first place.

More energy saving options are available, such as solar fans in attic spaces. But “just like the oil change in your car,” Eidson said, “regular HVAC maintenance is the key to running efficiently.”

Rudi Kiefer, Ph.D., is a professor of physical science and director of sustainability at Brenau University. His column appears Sundays and at gainesvilletimes.com.