Free standard shipping on orders over $149.97
Shop electric, natural gas and propane tankless water heaters (also called on demand hot water heaters) from Rinnai, Navien, Stiebel Eltron, Marey, Eccotemp and more. Clear specs, free shipping over $149.97.
Every kind of on-demand water heater, sorted by fuel and use.
Brands in the shop
RinnaiStiebel EltronMareyEccotempEZ TanklessChronomiteNavienNo storage tank to keep heated. The unit heats water as you open the tap.
Wall-mounted units free up the floor space a big tank would take.
Choose the fuel you already have, for indoor, outdoor or portable use.
Flow rate in gallons per minute (GPM) is what matters most. These are typical starting points, so always check each product page and your installation.
| Household | Typical flow | Usually suits |
|---|---|---|
| 1 to 2 people | 2 to 4 GPM | One bathroom or a kitchen |
| 3 to 4 people | 5 to 7 GPM | Family bathroom and kitchen |
| 5+ people | 8+ GPM | Several bathrooms at once |
Brand-new units, never installed.
Opened or returned units, checked before listing.
Manufacturer refurbished units at a lower price.
Read our product condition policy to see what each grade includes and how warranty coverage differs.
A tankless water heater heats water the moment you need it instead of keeping 40 or 50 gallons hot around the clock. That is why they are also called on demand water heaters, instant hot water heaters or instantaneous hot water systems: open the tap, the unit fires, and you get continuous hot water for as long as the flow and the unit's capacity allow.
We stock the main types in one place, with flow rate, fuel, venting and power requirements on every product page:
Still deciding whether to switch? Start with tankless vs tank water heaters and the honest list of tankless water heater pros and cons.
A tankless water heater, also called an on demand or instant hot water heater, heats water only when you open a hot tap. Water flows through a gas burner or electric elements and comes out hot, so there is no storage tank to keep warm and no tank to run out. See how a tankless water heater works.
Add up the flow rate (GPM) of the fixtures you run at the same time and the temperature rise your incoming water needs. Many homes with two bathrooms need 6–9 GPM from a gas unit, or a 24–36 kW electric unit in warm climates. Use our sizing calculator for a number specific to your home.
Units range from about $150–$600 for point-of-use and portable models to $800–$2,500 for whole-house gas units. Installed, most homeowners pay roughly $1,400–$4,500 depending on fuel, venting and whether gas lines or electrical service need upgrading. Our tankless water heater cost guide breaks it down.
No. Tankless Water Heater Shop is an online store and we do not offer installation, repair or maintenance services. We ship units to you and recommend installation by a licensed plumber, electrician or gas fitter who follows the manufacturer’s instructions and local code. Our installation guide explains what to expect and what to ask.
We ship to Worldwide. Orders leave our warehouse in 1–2 business days and typically arrive 5–17 business days after dispatch. Standard shipping is free on orders over $149.97. Full details are in our shipping policy.
Yes. You can return unused, uninstalled items in their original packaging within 30 days of delivery. Damaged, defective or incorrect items are replaced or refunded at no cost to you. Read the return and refund policy.
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