Verdict
The Best 5Reviewed by Mike Hun·May 20, 2026

Best Tankless Water Heaters

Top 5 tankless water heaters reviewed and ranked.

Quick answer

Stiebel Eltron Tempra 36 Plus is our top pick for tankless water heaters — an averaged 4.8/5 across 1 published review at about $812. Runner-up: Rheem RTEX-24 (~$485).

At a glance

Tap any product for the full review
(1 source)
$812Best for: whole-home electric tankless installs in mild climates
$812 · Check Price on Amazon
(1 source)
$485Best for: northern US homes with cold groundwater inlet
$485 · Check Price on Amazon
(1 source)
$540Best for: homes with 2-3 simultaneous showers in mild climates
$540 · Check Price on Amazon
(1 source)
$1,100Best for: northern homes with natural gas service
$1,100 · Check Price on Amazon
(1 source)
$300Best for: additions, outbuildings, sheds, and single-fixture installs
$300 · Check Price on Amazon
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Reviews aggregated from
ThisoldhouseBobvilaWaterheatersnowTanklessgeek

The full ranking

How we rank →
Stiebel Eltron Tempra 36 Plus
#1 · Top Score
Best for: whole-home electric tankless installs in mild climates
Stiebel Eltron Tempra 36 Plus
from 1 source$812

The Tempra 36 Plus is the best-overall pick — Stiebel Eltron's flow control handles whole-home demand without cold-water sandwiching.

Strengths
  • Advanced Flow Control prevents cold-water sandwiching
  • 36 kW max — handles whole-home demand in mild climates
Watch-outs
  • Requires 200A electrical service for full output
  • No Wi-Fi
Rheem RTEX-24
#2
Best for: northern US homes with cold groundwater inlet
Rheem RTEX-24
from 1 source$485

The RTEX-24 is the cold-climate pick — Rheem's flagship that handles northern winter inlet temps better than competitors.

Strengths
  • 3,900+ reviews proving reliability
  • Excels in cold-inlet conditions (northern climates)
Watch-outs
  • Slightly louder than Tempra under load
  • No advanced flow control
EcoSmart ECO 27
#3
Best for: homes with 2-3 simultaneous showers in mild climates
EcoSmart ECO 27
from 1 source$540

The ECO 27 is the high-flow pick — EcoSmart's best GPM-to-price ratio for households with multiple simultaneous hot-water demands.

Strengths
  • 6.6 GPM max — highest in this lineup
  • Compact unit saves install space
Watch-outs
  • Requires 240V triple-pole breaker
  • Some undersizing complaints below 40°F inlet
Rheem RTEX-13 Point-of-Use
#5
Best for: additions, outbuildings, sheds, and single-fixture installs
Rheem RTEX-13 Point-of-Use
from 1 source$300

The RTEX-13 is the point-of-use pick — Rheem's compact tankless for a single sink or shower. Best for additions and outbuildings.

Strengths
  • Point-of-use sized for single sink
  • Compact under-cabinet install
Watch-outs
  • Single-fixture only — not whole-home
  • 13 kW limits hot water flow

Spec comparison

5 products
SpecStiebel Eltron Tempra 36 PlusRheem RTEX-24EcoSmart ECO 27Rinnai V75iN Gas TanklessRheem RTEX-13 Point-of-Use
TypeElectric whole-homeElectric whole-homeElectric whole-homeNatural gasPoint-of-use electric
Power36 kW24 kW27 kW13 kW
Warranty10-year combinedLifetime elements
Max GPM6.67.5

Frequently asked questions

What is the best tankless water heater?
Stiebel Eltron Tempra 36 Plus is our top pick for tankless water heaters, with an averaged rating of 4.8/5 from 1 published reviews. The Tempra 36 Plus is the best-overall pick — Stiebel Eltron's flow control handles whole-home demand without cold-water sandwiching.
Is there a cheaper alternative worth considering?
Rheem RTEX-13 Point-of-Use (around $300) rates 4.5/5 in our analysis. The RTEX-13 is the point-of-use pick — Rheem's compact tankless for a single sink or shower. Best for additions and outbuildings.
How does Verdict rank these products?
Every rating on Verdict is the numerical average of scores published by independent review sites, YouTube reviewers, and Reddit buyer reports. No editor adjusts the order — the ranking is whatever the source data produces. See our methodology page for the full process.
When was this guide last updated?
This guide was last re-checked in May 2026. We re-run our research pipeline for each category on a rolling basis so prices and rankings reflect current market reality.

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