You can help save the planet while also saving cash, according to the Alliance to Save Energy.

The average U.S. household spends about $3,425 to power a car and $2,175 on home energy costs--in other words, about $5,600 on energy costs per year. That number is likely even greater with rising fuel and utility costs.

In honor of Earth Day, the Alliance to Save Energy is offering up some pointers on how to trim those yearly expenses with some easy ways to go “green.” Here are a few of its tips.

In your car:

• Use cruise control. Cruise control on the highway can help you maintain a constant speed, which can help save gas.
• Use the overdrive gear. By using the overdrive gear, your car’s engine speed goes down, which not only saves gas but also reduces engine wear and tear.
• Slow down. Driving anything above 60 miles per hour is decreases your gas mileage rapidly. The Alliance equates it to every 5 mph over 60 mph that you drive is basically like paying 24 cents per gallon for gas.

In your home:

• Swap out the light bulbs. Replace old incandescent bulbs with energy efficient options such as compact fluorescent lights, which can shave up to $50 off your electricity costs over the lifetime of each bulb, even factoring in the higher purchase price of the bulb.
• Plant a tree. Properly positioned trees outside your home actually have been found to reduce a home’s energy use, even up to 50 percent during the summer months and 15 percent in the winter.
• Get a tax break. Uncle Sam is offering 2011 tax breaks of up to $500 for energy efficiency home improvements, such as with Energy Star windows, insulation, or energy efficient heating and cooling equipment. Learn more.

Source: “Already-Soaring Gas Prices Make Energy Efficiency an Apt Way to Honor Earth Day While Saving Money, Says Alliance,” Alliance to Save Energy (April 19, 2011)