For homeowners

Tankless water heater vs tank: which fits your home?

Choose Tankless (on-demand) for energy efficiency in a home that uses 41 gallons or less of hot water a day; Storage tank for replacing a tank that usually meets your needs.

The right choice depends on how much hot water the household uses each day, how many fixtures run hot water at the same time, and whether the gas line and power at the heater suit a tankless unit.

How we know: By InstaBids editorial team with AI research agents. · Sources read: 22 October 2026 · Updated 27 October 2026

DOE's Energy Saver Guide (2022): "On-demand or tankless water heaters (gas) heat water directly without using a storage tank."
Factor	Tankless (on-demand)	Storage tank
Energy efficiency in a home that uses 41 gallons or less of hot water a day	DOE (2022), for gas on-demand models: can be 24%–34% more energy efficient than conventional storage tank water heaters	DOE (2022): the conventional storage tank water heater is the baseline of that comparison
Energy efficiency in a home that uses a lot of hot water, around 86 gallons a day	DOE (2022), for gas on-demand models: can be 8%–14% more energy efficient	DOE (2022): the conventional storage tank water heater is the baseline of that comparison
Energy lost while the heater stands by	ENERGY STAR: heats water only when needed, eliminating energy lost during standby operation	ENERGY STAR: maintains a tank full of hot water at all times
How capacity is rated	ENERGY STAR: by how many gallons of hot water it produces per minute (GPM)	ENERGY STAR: by the number of gallons that will fit in the tank (gas storage)
Hot water in several places at the same time	DOE (2022): you may find you need two or more tankless water heaters	ENERGY STAR: the first-hour rating measures how much hot water the unit can deliver during a busy hour
Replacing a tank that usually meets your needs	ENERGY STAR: the installer should determine whether the existing natural gas line is sufficient and whether electricity is available near the water heater (forced ventilation models)	ENERGY STAR: you can probably replace it with one the same size
Expected life	DOE (2022): tankless water heaters "can last more than 20 years"	DOE (2022): "Most storage water heaters last 10-15 years"
Space	ENERGY STAR: gas tankless water heaters are small and wall-mounted	ENERGY STAR contrasts them with bulky tank-type water heaters
Routine upkeep the sources name	no official figure	DOE (2022): drain a quart of water from the tank every 3 months to remove sediment
Minimum warranty to earn the ENERGY STAR label (gas models)	ENERGY STAR: at least 6 years on the heat exchanger and 5 years on parts	ENERGY STAR: at least 6 years on the system, including parts

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energy efficiency in a home that uses 41 gallons or less of hot water a day	Tankless (on-demand)

What does water heater replacement cost?

For water heater replacement prices, see How much does water heater replacement cost?

Something already failing? See Tankless water heater repair or replace: which fits your home?

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Sources for the facts on this page

U.S. Department of Energy, Energy Saver Guide (2022), government, read 22 October 2026.
ENERGY STAR (U.S. EPA / DOE), How It Works: Whole-Home Gas Tankless Water Heaters, government, read 22 October 2026.
ENERGY STAR (U.S. EPA / DOE), Whole Home Tankless Gas Water Heaters, government, read 22 October 2026.
ENERGY STAR (U.S. EPA / DOE), How It Works: High-Efficiency Gas Storage Water Heaters, government, read 22 October 2026.
ENERGY STAR (U.S. EPA / DOE), High Efficiency Gas Storage Water Heaters, government, read 22 October 2026.
ENERGY STAR (U.S. EPA / DOE), gas tankless water heater benefits page, government, read 22 October 2026.
ENERGY STAR (U.S. EPA / DOE), Water Heater Key Product Criteria, government, read 22 October 2026.