At a Glance

Warranty: 5-year limited

Super High Efficiency

Family Size: 3-4 People

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A.O. Smith Signature Series 240-Volt 22-KW 4.3-GPM Tankless Electric Water Heater

Name: A.O. Smith Signature Series 240-Volt 22-KW 4.3-GPM Tankless Electric Water Heater
Brand: A.O. Smith
SKU: 1000550107
Price: 509 USD
Availability: InStock
Rating: 3 (468 reviews)

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468

Wattage (Watts): 22000

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Equip your home to deliver continuous hot water for 1 shower (calculations are based on a 2.5 GPM showerhead in the southern zone) by installing this A. O. Smith Signature Series tankless electric water heater. Perfect for applications such as cabins, apartments and small homes, this unit only heats water when it's needed for potential energy and money savings. This tankless hot water heater also mounts on the wall to save you valuable storage space, and the soft start design enables a softer electric draw when powering on to reduce light dimming. Keep in mind that professional installation is recommended for a tankless water heater since these units typically require greater electrical supply capacity than standard tank-type models. Please ensure your home can support the 66.7 amps, 2 x 40-amp double pole breakers, 8 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 2 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	Use Location	Indoor
Type	Tankless	Display Type	Digital
Power Source	Electric	Installation Type	Wall mount
Grade	Residential

Dimensions
Depth (Inches)	6.13	Water Connection Size	3/4-in
Family Size	4	Weight (lbs.)	20
Height (Inches)	18.13	Width (Inches)	11.5

Features
Annual Fuel Utilization Efficiency % (Percentage)	0	Scale Prevention	Yes
Grid Capable	No	Super High Efficiency	Yes
Hybrid Heat Pump Technology	No	Uniform Energy Factor	0.92
Installation Location	Wall	Voltage (Volts)	240
Leak Detection	No	Water Heater Style	Tall
Maximum Gallons per Minute	4.3	Wattage (Watts)	22000
Point of Use	No

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

3 out of 5

468 Reviews

45% Recommend this product

Ratings may include incentivized customer reviews.

Read All Reviews

+ 25

What Customers Are Saying

Customers are sharply divided on this tankless water heater. Many praise its compact design, instant hot water delivery, and improved water taste. However, nearly as many report serious problems: repeated failures with error codes E02, E03, and E06 appearing within months, internal leaks, burned circuit boards, and dangerous temperature swings between scalding and cold water. Several describe replacing failed units only to receive defective replacements. Some note the system works in only one fixture or shuts down unexpectedly. Installation often requires costly electrical upgrades. Overall, experiences are polarized—some find it worthwhile, but many consider it unreliable and potentially unsafe.

Customer review summary generated by AI, including incentivized reviews.

468 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
From Signature Series 240-Volt 28-KW 5.5-GPM Tankless Electric Water Heater

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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