This section looks at the environmental impact of our energy consumption, some simple ways to use less of it, and the many positive benefits that can result.

Home heating and cooling: 45 percent
In most households, heating and cooling account for the biggest single chunk of your energy bill. The good news is there are many ways to cut those costs.

Choose energy-efficient furnaces or air conditioners that are the right size for your home.

Properly insulate your home (especially the attic), including the duct system.

Contact your utility company for a free energy audit. If your utility company doesn’t offer free audits, try the do-it-yourself tool, from the Department of Energy and the Environmental Protection Agency.

Programmable thermostats, insulated windows, and ceiling fans can also help lower your energy bill. A programmable thermostat, for instance, can cut heating and cooling costs as much as 20 percent when you use it to reduce the temperature 5 degrees at night and 10 degrees during the day when heating (or raise it an equal amount when cooling). Watch how we test programmable thermostats and get recommendations on choosing a thermostat (full report available to subscribers).

Hot water: 11 percent
Overall, water-heater technology hasn’t changed much in recent years. There are, however, newer, instantaneous heating models (with no tank) that can save you up to $50 a year in energy costs, although they cost more initially. Solar hot-water heaters are gaining in popularity as an alternative for or supplement to conventional water-heating units. For more information, visit the Department of Energy online or National Center for Photovoltaics.

Set your water heater to 120 degrees, it can save up to 10 percent in water-heating costs compared to a 140 degree setting.

Wrap an insulation blanket around your hot water pipes and storage tank.

Replace a showerhead that is more than 10 years old with a low-flow model. It can save up to half the hot water used for showering.