For the most part, yes There are a few left with standing pilot lights, but all the major manufacturers have switched 99% of their product line to electronic ignition. Another reason you need power is the modern whole house tankless water heaters have a sealed exhaust system and a fan that pushes the exhaust out the vent pipe. Tankless units also have a built in freeze protection system, which requires a small amount of electricity when the heater is plugged in. Although losing power is rare, we do recommend that every tankless owner purchase and install a simple Battery Backup device (UPS) and plug the tankless power into it. These battery backups are usually used with computers, and will run a tankless water heater for 20-40 minutes in the event of a power outage, and they also protect the tankless water heater from power surges. The biggest reason for the battery backup however, is to ensure you don’t lose hot water if you happen to be IN the shower when the power goes out. There are no battery backup devices that will run an electric tankless water heater.