Turn Down Your Water Heater
While many conventional water heaters are set to 140 degrees F by installers, most households don't need that level, and end up paying for hot water that just sits around, slowly cooling. Lowering the temperature to 120 would reduce your water heating costs by 6 to 10%.
Give it a try. Many people find that tweaking the dial can be addictive, and it's easy to reduce the temperature further to 115 or even lower.
