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Best 110 Volt Tankless Water Heater For Shower

3 expert-curated picks ranked by performance, value, and long-term reliability

110V (or 120V) tankless water heaters for shower applications are a very specific niche product. Most US residential outlets are 120V; a true 110V system implies older wiring or commercial specifications. The category mostly refers to small electric tankless units that operate on standard household electrical service without requiring 240V circuits. This list is honest about what these units can and cannot do.

The physics constraint

A 120V single-phase residential circuit at 20A maximum delivers about 2,400 watts of power. To heat water at a useful rate for showering — even a low-flow shower at 1.5 GPM with a 40°F rise — requires roughly 8,800 watts (8.8 kW). A 120V circuit physically cannot supply that much power.

Two practical paths exist:

  1. Accept very low flow (under 0.5 GPM): a 2,400W unit can heat about 0.4 GPM at a 40°F rise. Adequate for handwash, inadequate for any normal shower.
  2. Use a mini-tank (stores hot water, slow recovery): a 120V unit with a 4-gallon reservoir can deliver a brief shower of 4 gallons total before running cold for 30+ minutes.

True whole-house electric tankless requires 240V at high amperage. There is no 120V whole-house electric tankless because the physics does not allow it.

Picks for shower applications

For "trickle shower" handwash use: EcoSmart POU 3.5

3.5 kW unit on 240V (not 120V). Single 20A double-pole breaker (different from a 20A single-pole 120V circuit). Delivers about 0.5 GPM at a 40°F rise — workable for handwash, not for any meaningful shower.

For brief outdoor camp showers: Eccotemp L5 (propane, not electric)

Battery-fired propane outdoor unit. 37,500 BTU = approximately 11 kW thermal output, far exceeding what any 120V electric unit can do. About $190 unit. The right answer for camp showers where AC power is unavailable.

For temporary cabin shower with 120V only: EcoSmart ECO MINI 4-gallon mini-tank

Not technically tankless — a 4-gallon storage tank with 120V 1440W element. Stored 4 gallons of hot water provides a 2–3 minute shower at 1.5 GPM. Then 25+ minutes to recover. Workable for very light use; inadequate for daily shower demand.

For RV use where 120V shore power is the only power: a true 240V tankless via dual 30A inverter

Some RV setups use a 30A 240V split-phase inverter from a generator + shore power to power a small 11 kW tankless. Complex install, expensive setup, only worth it for specific extended-stay RV scenarios.

What actually works for showers

For shower applications specifically, the choices that genuinely work:

  • 240V whole-house electric tankless: EcoSmart ECO 18 or 27, Rheem RTEX-18 or 24. Require 240V circuits and 100A+ service.
  • Gas tankless: propane or natural gas. Independent of household electrical capacity.
  • Standard electric tank: 240V circuit, stores 40+ gallons of hot water for shower use.
  • Heat-pump tank: 240V circuit, much lower amperage than tankless. Best for primary residences.

If your install location truly only has 120V available

You have three honest options:

  1. Add a 240V circuit. An electrician can install a 240V 30A or 40A circuit for $200–$500 in most homes. This unlocks all standard residential water heater options.
  2. Use propane gas instead. Eccotemp L10, Marey GA10LP, or similar outdoor propane tankless. Battery-fired ignition needs no AC power at all.
  3. Accept the mini-tank limitation. 4–6 gallon 120V storage units for very light use. Adequate for occasional cabin use, inadequate for daily shower demand.

If a salesperson is offering you a "120V tankless for shower" without one of the qualifications above, the product is either misrepresented or designed for handwash-only use that the marketing is obscuring.

3 products
$949 – $1,795
Updated May 2026

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