Does a Gas Tankless Water Heater Need Electricity?

If you're shopping for a gas tankless water heater, you may wonder whether it needs to be plugged in. After all, it's a gas appliance, right? Yes, these units do need electricity—but not to heat your water.

Gas tankless water heaters require a small amount of power to run the electronic ignition, control board, display, and safety systems. Think of it like your gas furnace or a gas stove: they burn gas for heat, but still need electricity to spark the burner and control operation.

The cost of gas tankless water heaters pays off over time through lower energy bills and the convenience of endless hot water.

Electronic Ignition: The Spark That Starts Your Hot Water

The electronic ignition system is what starts your gas tankless water heater. When you turn on a hot water tap, the control board detects the flow and tells the ignition system to create a spark to ignite the burner. This doesn't take long, so you get hot water very quickly. Older water heaters used pilot lights that burned gas around the clock, even when you weren't using hot water. Electronic ignition only fires when needed, which saves energy and reduces your utility bills. The system uses less power than a standard light bulb.

Control Board and Safety Sensors

Your gas tankless water heater has a control board that manages the entire heating process. The control board reads incoming water temperature and adjusts the gas flow to hit your target temperature. Digital sensors track water flow rate, temperature, and pressure, sending constant updates to the control board. This system keeps your hot water at a steady temperature. A display also shows error codes when an issue occurs, allowing you to identify problems quickly.

Blowers and Safety Systems That Keep You Protected

Many gas tankless water heaters have electric blowers that pull in fresh air and push exhaust gases outside. This keeps harmful fumes out of your home. Safety sensors need electricity too. These sensors watch for overheating, flame failure, or blocked vents. When they detect an issue, the control board shuts down the unit.

How This Compares to Other Water Heaters

Gas storage water heaters may also need electricity for their control systems if equipped with electronic ignitions. Both types use similar amounts of power for electrical components—the main difference is in how they heat water. Tank water heaters keep a reserve of hot water ready at all times, which works well for households with predictable usage patterns. Gas tankless water heaters heat water on demand as you use it, which can cut down on gas use in some homes.

What Happens During a Power Outage

Gas tankless water heaters need electricity to run, so they stop working during power outages. This is true for most water heaters used today, including newer gas tank models with electronic ignition. If power outages are common in your area, battery backup systems are available for tankless water heaters to keep them running when the power goes out.