A gas heater with a standing pilot light or a gas heater with electronic ignition.
The pilot light must remain lit at all times while the electronic ignition lights itself. The pilot light can be lit by following the simple instructions in the manual. You will set the gas valve dial to PILOT, hold it down, and press the ignitor button. The pilot generator will let out a little gas, and the ignitor creates the spark. Once you have visually verified that there is a small flame present, set the the valve to ON. That's it! If the pilot light should blow out, you must relight it. This heater requires no electrical wiring.
The electronic igintion heater will have a HOT SURFACE IGNITOR or a SPARK IGNITOR which ignites the gas every time it turns on. The valve is set to either ON when in use or OFF when not in use. There is no need for a pilot light. That's it! This heater requires an electrical connection.