Electric Tankless Water Heaters Worth Buying in 2026

Our picks for the best electric tankless water heaters for whole homes, small homes and single sinks, plus the electrical service you'll need before you buy.

By Tyler RamirezUpdated October 29, 2026How we pick products

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An electric tankless water heater heats water only when you turn on the tap, so there’s no tank to keep hot and no running out halfway through a shower. They’re compact, efficient and don’t need venting like gas units.

The catch is electricity. Whole-house electric tankless heaters draw a lot of power, and many homes need electrical upgrades before they can run one. Read the sizing section below before you buy.

Side by side

Flow ratings assume a modest temperature rise in a warm climate; expect roughly half the flow when incoming water is very cold. Specs are from manufacturer listings and reviews by Bob Vila and This Old House. Prices are typical October 2026 prices.

1. Stiebel Eltron Tempra 36 Plus: Best overall

Good fit for: Larger homes that want the most consistent whole-house hot water from an electric unit.

Stiebel Eltron is the premium name in electric tankless heaters, and the Tempra 36 Plus is a favorite of Bob Vila and This Old House. Its Advanced Flow Control slightly reduces flow when demand exceeds what it can heat, so the water stays hot instead of going lukewarm. It’s about 99 percent efficient, quiet, and comes with a 7-year leak and 3-year parts warranty.

What bugs us: It’s the most expensive pick, it needs three 50A breakers, and like every electric unit, flow drops sharply with very cold incoming water.

Skip it if: your panel can’t handle about 150 amps for the heater alone.

2. EcoSmart ECO 27: Best value whole house

Good fit for: Homes in warm or mild climates that want whole-house tankless for less.

The ECO 27 costs hundreds less than the Stiebel Eltron and handles a typical home in a warm climate, rated at 6.6 GPM. It adjusts its power to match demand, sets temperature in 1-degree steps, and has a lifetime warranty on the heat exchanger.

What bugs us: It needs three 40A breakers, and with 37°F incoming water its flow drops to about 3 GPM, enough for one shower at a time. It lacks Stiebel’s flow control.

Skip it if: you live somewhere with very cold winters and need several showers at once.

3. Rheem RTEX-24: Best for two bathrooms

Good fit for: Two-bathroom homes in warm to moderate climates.

The RTEX-24 hits a sweet spot between the small and large units, with enough flow for two fixtures at once in most conditions. It self-modulates to save energy and is easy to find in stock.

What bugs us: It still needs three 40A breakers, and it won’t keep up with a big household in a cold climate.

Skip it if: you have three or more bathrooms in use at once.

4. Rheem RTEX-13: Best for small homes

Good fit for: Condos, cabins, tiny homes, additions and apartments.

This compact unit runs on a single 60A breaker, which makes it far easier to install than whole-house models. It’s about 99 percent efficient with a digital display.

What bugs us: It handles only one or two fixtures at a time.

Skip it if: you need hot water for a full family home.

5. Rheem RTEX-06T: Best point of use

Good fit for: A single sink far from the main water heater, or a garage or workshop.

Installed under a sink, this small heater delivers instant hot water so you’re not running the tap waiting for it to warm up. It needs only a 30A circuit.

What bugs us: It’s not built for showers, especially in cold climates.

Skip it if: you want whole-house hot water. For hot water at the kitchen sink specifically, see the best instant hot water dispensers.

How we chose these

We compared electric tankless heaters recommended by Bob Vila and This Old House, along with manufacturer specs, focusing on:

• Flow in warm and cold climates
• Electrical requirements, which often decide what’s practical
• Temperature stability and features
• Warranty and price

We haven’t tested these ourselves. Installation involves high-amperage wiring; have a licensed electrician confirm your panel can support the unit. Read more about how we pick products.

How to size an electric tankless heater

1. Know your temperature rise

Subtract your incoming water temperature from the temperature you want (usually about 105 to 120°F). Incoming water can be 70°F in the South and below 40°F in northern winters. A bigger rise means much less flow.

2. Add up your flow

Typical flows: a shower uses about 1.5 to 2.5 GPM, a kitchen faucet about 1.5, a dishwasher about 1 to 1.5. Add up what you’ll run at the same time.

Our guide to what size tankless water heater you need walks through it with examples.

3. Check your electrical service

Whole-house electric units commonly need 113 to 150 amps and a 200-amp panel. If you have a 100-amp service, a panel upgrade can cost $1,000 to $3,000 or more. Get an electrician’s load calculation before buying.

Is electric tankless worth it?

It can be, especially in warm climates, for small homes, or where gas isn’t available. In cold climates, gas tankless or a heat pump water heater may be a better fit. Here’s an honest look at tankless vs tank water heaters.

Questions people ask

Can an electric tankless heater run two showers at once? Yes, if it’s sized for your climate. A 27 to 36 kW unit can in warm areas; in cold areas, even large units may manage only one or two.

Do electric tankless heaters need venting? No, which is one of their biggest advantages.

Are tankless heaters good for RVs? Usually propane models are used in RVs. See the best tankless water heaters for an RV.