At a Glance

Warranty: 5-year limited

Super High Efficiency

Family Size: 5+ People

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A.O. Smith Signature Series 240-Volt 28-KW 5.5-GPM Tankless Electric Water Heater

Name: A.O. Smith Signature Series 240-Volt 28-KW 5.5-GPM Tankless Electric Water Heater
Brand: A.O. Smith
SKU: 1000601621
Price: 629 USD
Availability: InStock
Rating: 2.8 (392 reviews)

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2.8

392

Wattage (Watts): 28000

Pickup

Unavailable

Shipping

Wed, Oct 14

20 available

Delivery

Thu, Oct 22

5,000+ available

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Simplify your morning routine with this A. O. Smith tankless water heater that delivers enough continuous hot water for 1 shower and 4 sinks (based on a 2.5 GPM showerhead in the southern zone) when sized appropriately. This Signature Series electric tankless hot water heater makes a great choice for applications such as cabins, apartments, and small homes since the unit only heats water when it's needed for potential energy and money savings. This small tankless electric water heater also mounts on the wall, saving you valuable storage space, and the soft start design enables a softer electric draw when powering on, reducing light dimming. Keep in mind that professional installation is recommended for a tankless hot water heater since these units typically require greater electrical supply capacity than standard tank-type models. Please ensure your home can support the 116.7 amps, 2 x 60-amp double pole breakers, #6 AWG wire size and 240-volt water heater wiring required for this model and that you have enough space in your breaker panel. Call 1-877-GOLowes to get this water heater installed.

Delivers the ideal amount of continuous hot water for 1 shower and 4 sinks when sized appropriately (0.5 GPM faucets and 2.5 GPM showerhead)
Frees up valuable storage space with compact design
Offers easy wall mount installation that uses standard 3/4-in NPT water connections and doesn't require venting
Has no moving parts for simple maintenance and uses standard heating elements for easy replacement
Reduces harmful mineral deposits and extends product life with scale reduction technology and heat element power sharing
Dry-fire protection prevents premature element failure for worry-free installation
Enables simple temperature adjustment from 90 to 140 degree F via an intuitive digital interface
Provides peace of mind with a 5-year limited chamber guarantee and a 1-year limited parts and labor warranty
Try our product selector tool to see if this is the right water heater for you

General
Series Name	Signature Series	Grade	Residential
Type	Tankless	Use Location	Indoor
Power Source	Electric	Installation Type	Wall mount

Dimensions
Depth (Inches)	6.13	Water Connection Size	3/4-in
Family Size	5	Weight (lbs.)	19.75
Height (Inches)	18.13	Width (Inches)	17

Features
Grid Capable	No	Scale Prevention	Yes
Hybrid Heat Pump Technology	No	Super High Efficiency	Yes
Installation Location	N/A (Portable)	Uniform Energy Factor	.92
Maximum Gallons per Minute	5.5	Voltage (Volts)	240
Point of Use	No	Wattage (Watts)	28000

Compatibility
Bluetooth Compatibility	No	Works with iOS	No
Smart Compatible	No	Works with SmartThings	No
Wi-Fi Compatibility	No	Works with the Google Assistant	No
Works with Amazon Alexa	No	For Use with Mobile Homes	No
Works with Android	No	For Use with RVs	No
Works with Apple HomeKit	No

Warranty
Warranty	5-year limited

Certifications
CA Residents: Prop 65 Warning(s)	Prop 65 WARNING(S) -	Safety Listing	UL safety listing
ENERGY STAR Certified	No	AHRI Certified	Yes

Miscellaneous
UNSPSC	40101800

Check out the Best Selling Water Heaters on Lowes.com

Review

2.8 out of 5

392 Reviews

41% Recommend this product

Ratings may include incentivized customer reviews.

Read All Reviews

+ 22

What Customers Are Saying

Customers are sharply divided on this tankless water heater. While some appreciate instant hot water and compact design, most report recurring technical failures—especially error codes E02, E20, E03, E04, and E06—often within months. Many describe sudden leaks from seams and connections, inconsistent water temperatures cycling between scalding and freezing, and moisture detection malfunctions. Warranty support is widely criticized as inadequate, with customers unable to return defective units. Installation demands specialized electrical work including double 60-amp breakers. Despite some positive experiences, reliability issues and poor warranty service leave most customers dissatisfied.

Customer review summary generated by AI, including incentivized reviews.

392 Customer Reviews

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Worst Water Heater Ever - DO NOT BUY!

Would Not Recommend

We have bought TWO of these units at Lowe's. Both units leaked shortly after installation. This unit obviously has manufacturing defects, yet Lowe's continues to sell this product. WHY???? We bought the 5-year extended warranty and have already returned one of the two units we purchased. We're on the way to Lowe's today to return the second unit we bought because ... you guessed it ... it's leaking. What an exercise in ridiculosity. Run, don't walk, away from this unit!

thelion99September 21, 2026
From Signature Series 240-Volt 14-KW 2.7-GPM Tankless Electric Water Heater Verified Purchaser

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Response from Published by the A. O. Smith Team

We're sorry to hear of your experience.

We want to ensure you receive the warranty coverage included with your purchase.

Pl... Read More

Published by the A. O. Smith TeamSeptember 21, 2026

Easy to follow onstallation guide

Very easy installation. Unit is low profile ideal for small mechanical rooster or closets.

Jose2026September 16, 2026
From Signature Series 240-Volt 14-KW 2.7-GPM Tankless Electric Water Heater Verified Purchaser

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Water heater

TeTeSeptember 12, 2026
From Signature Series 240-Volt 18-KW 3.5-GPM Tankless Electric Water Heater Verified Purchaser

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Do not buy

Would Not Recommend

Constantly broken or showing error codes. Has had to be repaired three times in one year. Very temperamental and unreliable.

SkipSeptember 11, 2026
From Signature Series 240-Volt 14-KW 2.7-GPM Tankless Electric Water Heater

Was this Review Helpful ?

Response from Published by the A. O. Smith Team

We are sorry to hear of your experience. We want to ensure the issue is resolved.

Please send your phone number to talktous@aosmith.co... Read More

Published by the A. O. Smith TeamSeptember 15, 2026

Circuit panel faulty

Would Not Recommend

Unit less than 2 years old , circuit panel burned up 2x. Was installed by licensed professional that I trust so breakable due to faulty equipment. Would not purchase again. Circuit panel replacement cost more than the unit itself. Warranty will not cover defective product.

No thanksSeptember 2, 2026

Was this Review Helpful ?

Response from Published by the A. O. Smith Team

We're sorry to hear of your experience.

We want to ensure you receive the warranty coverage included with your purchase.

Pl... Read More

Published by the A. O. Smith TeamSeptember 4, 2026

Nice piece of equipment

Would Recommend

Good working unit. Does require some serious wiring though.

PlumberAugust 27, 2026
From Signature Series 240-Volt 18-KW 3.5-GPM Tankless Electric Water Heater Verified Purchaser

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