We've all heard the saying, "What a difference a day makes." Today could be your opportunity to make a difference by reducing your home's impact on the environment. Surprisingly, one of the most beneficial ways is to use less energy to heat and cool your home ... and it starts with adding insulation.

Insulation is the single most cost-effective way to reduce greenhouse gas emissions, according to a study by the McKinsey Global Institute. Because saving energy helps reduce greenhouse gas emissions, using less has a payback that is both personal and global: you'll save money and shrink your personal carbon footprint.

"Most people don't realize that the energy used in homes and buildings, much of it for heating and cooling, is the single greatest source of energy consumption in the country, more than industry, more than transportation," said Gale Tedhams, director of sustainability for Owens Corning, makers of PINK fiberglass insulation. "Conservation should be thought of as your first fuel because energy you don't have to use is the cheapest energy you can buy."

The following tips, each of which takes just a few moments to complete, have a measurable impact on reducing your home energy usage this summer and year round. Best of all, they can be accomplished in just one day.

6:30 a.m. -- Before heading to the shower, check the temperature of your water heater. Some manufacturers set thermostats at 140 degrees, but according to the U.S. Department of Energy, most households need only a setting of 120 degrees. The DOE notes that water heating accounts for 14 to 25 percent of home energy used and each 10-degree reduction in water temperature can save between 3 and 5 percent in annual energy costs.

8 a.m. -- Close the curtains against the summer sun before you head out the door for the day. The easiest way to save energy on cooling is to reduce your air conditioning needs in the first place. Heating and cooling accounts for more than half of a typical home's annual energy usage, so you can make a big impact while also making your home more comfortable.

10 a.m. -- Visit the Web site of your local home improvement center and order a programmable thermostat. You can save as much as 10 percent per year on your cooling bills by automatically adjusting the temperature of your home while you are sleeping or away.

Noon -- Take a home energy audit. Understanding how much energy a home uses helps homeowners determine what changes will save them the most energy and money. For an easy home energy audit, The Home Report Card quiz found at www.OwensCorning.com/HomeReportCard provides tailored recommendations for improving home energy efficiency.

6 p.m. -- While dinner is in the oven, take a moment to peek into your attic. If you can see the wood beams of your attic floor, chances are your house is one of 60 million under-insulated American homes. The DOE recommends an average of R-49 in the attic for maximum energy efficiency. If you have less than 15 1/2 inches of insulation in your attic, you don't have enough. Visit www.InsulateYourAtticNow.com to determine the recommended amount of insulation for your region of the country and find a local retailer.

8 p.m. -- Before you sit down to read a bedtime story to your kids, replace the bulb in your lamp with a compact fluorescent. Compared to standard incandescent bulbs, compact fluorescents used about one-fourth the energy, produce 90 percent less heat and last up to ten times longer.

With warm summer temperatures just around the corner, today is a great day to make a difference. A few simple steps to save energy will have lasting benefits for your budget and for the planet, and all can be accomplished in just one day. You'll be surprised what a difference a day can make.