If your hot water heater feels warm when you touch it, it could use some extra insulation. Fortunately, doing it yourself is easy. Your local big box store should have a pre-cut insulating blanket that fits nice and snug around your existing hot water heater. This $20 purchase will pay for itself in a year by saving you up to 10 percent in water heating costs. It also improves your air quality by cutting down on carbon dioxide emissions.