Tankless

Tankless refers to a technology or product category that heats water without a storage tank, delivering hot water on demand rather than storing it. The term is most commonly applied to water heaters.

In a tankless water heater, water flows through a heat exchanger only when a hot-water tap is opened. A flow sensor detects demand and, depending on the model, an electric element or a gas burner heats the water to the desired temperature. Modern units may modulate heat output to maintain a steady delivery as flow or temperature requirements change.

Types include electric tankless heaters, gas-fired tankless heaters (condensing and non-condensing), and combinations designed for whole-house or point-of-use installations. Some systems are designed for single fixtures, while others are sized for simultaneous hot water throughout a home.

Benefits commonly associated with tankless systems include reduced standby heat loss, space savings, and potentially lower energy use over time. Limitations can include higher upfront cost, installation complexity, and limited flow rate; multiple units or larger service feeders may be required to sustain high-demand periods. Gas units require venting and adequate combustion air; electric units may draw substantial electrical capacity.

Adoption varies by region and is influenced by climate, energy prices, and local building codes emphasizing efficiency. Choice among models depends on household hot-water demand, water temperature requirements, water hardness, and available utilities.