Why do most gas appliances have electronic ignition, while gas water heaters have pilot lights. It does seem a bit odd that most gas appliances such as cook tops, ovens and furnaces have electronic ignition, while gas water heaters have a pilot light that burns continuously. While pilot lights on other appliances waste gas, those on water heaters save energy because the heat generated by the pilot light gently burning beneath the tank helps maintain the temperature of its heated water. Thus, the gas used to fuel its pilot light is not wasted. It prolongs the time between full heating cycles and ultimately saves money. For even greater savings, add a thermostat temperature setting. Also should its flame ever go out, a device called a thermocouple shuts off the gas. And that's the On The House tip for today.