What is a tankless water heater?

A tankless water heater, also called an on-demand or instantaneous water heater, heats water directly as you draw it from the tap, eliminating the need for a storage tank. When you turn on hot water, cold water flows through a heat exchanger (usually powered by natural gas, propane, or electricity) and exits at your desired temperature.

Unlike tank heaters that maintain a constant supply of hot water, tankless systems only consume fuel when hot water is actually needed. This makes them suited to households with variable demand throughout the day.

Tankless units are sized by their flow rate, measured in gallons per minute (GPM). A typical New England bathroom shower uses 2 to 2.5 GPM, while a kitchen sink uses about 1 to 2 GPM. Homeowners need to choose a unit that can meet their peak simultaneous demand, such as running a shower and washing clothes at the same time. Common residential models deliver 5 to 10 GPM.

In Greater Hartford and the wider New England region, tankless heaters usually run on natural gas (the most efficient option if your home has gas service) or propane in areas without gas lines. Electric tankless models exist but require significant electrical upgrades for sufficient power. Plumbers in the area assess your home's fuel type, water usage patterns, and available space when recommending whether a tankless unit fits your situation.