According to Energy Star, good insulation can save up to 20 percent in energy costs. To be sure of how much insulation you need, find your location on the Energy Star map and look for the corresponding R-value.
Appliances draw a great deal of power, so it pays to turn to energy-efficient models. The appliances in your home account for up to 20 percent of your costs, according to the U.S. Department of Energy. By going with Energy Star products, you can reduce your home's energy and water usage by 10-15 percent.
Speaking of energy-efficiency, few things can help lower your heating bills like a programmable thermostat. According to the U.S. Department of Energy, turning the thermostat down 10 to 15 degrees for eight hours each day can save up to 15 percent on heating costs.
Fifteen percent of your utility bill goes to that old water heater, according to the DOE. If your tank is ancient, look into a tankless or on-demand water heater. A solar water heater can save a whopping 90 percent on operating costs.
The little things count, too
As you make these big changes, look to the smaller things, too. Close up drafts with caulk and weather-stripping, insulate switches and outlets, and unplug your appliances when they aren't in use. To get even more ideas, invest in a home energy audit that can help you pinpoint what needs work.