Name: A.O. Smith Signature 100 50-Gallon Tall 9-year Warranty 40000-BTU Natural Gas Water Heater
Brand: A.O. Smith
SKU: 1000542593
Rating: 4.5 (2758 reviews)

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Shipping Details

The Signature 100 Series Tall A. O. Smith 50-Gallon Gas Water Heater with Low NOx Atmospheric Vent provides efficient, reliable hot water for households with 5-6 people when sized appropriately. The environmentally friendly 40,000 BTU Low nitrogen oxide gas burner delivers 84 gallons of hot water in the first hour. Its electronic gas valve provides precise temperature control for optimum hot water delivery without an external power source needed. The gas valve also has a convenient LED status indicator for diagnostics reporting and a push-button ignition to simplify startup. This A. O. Smith natural gas water heater has a built-in safety system to reduce the risk of accidental flammable vapor ignitions. A factory-installed temperature and pressure relief valve and tamper-proof drain valve also ensure safe operation. This model is built to last. It features Tank Guard® which is designed to provide ultimate tank protection and increase lifespan of the water heater. This added protection comes with a 9-year limited warranty to provide peace of mind. Call 1-877-GOLowes to get this water heater installed.

Delivers the ideal amount of hot water for households with 5-6 people when sized appropriately
Features an environmentally-friendly 40,000 BTU gas burner that delivers 84 gallons in the first hour
Electronic gas valve provides precise temperature control for optimum hot water delivery
Self-diagnostic electronic gas control incorporates an LED status indicator that monitors and reports on the system's operational status
Built-in safety system reduces the risk of accidental flammable vapor ignitions
Tall, slim 60.75-in H x 22-in diameter profile enables easier installation in narrow spaces
Tank Guard® provides advanced tank protection that extends the life of your gas water heater
High-altitude certified from 0 ft to 10,100 ft
Provides peace of mind with a 9-year limited tank and parts guarantee and a 2-year limited labor warranty

General
Type	Tank	Power Source	Gas
Fuel Type	Natural gas	Use Location	Indoor
Grade	Residential	Series Name	Signature 100
Ignition Type	Piezo	Venting Type	Atmospheric
Vent Type	Type B double wall

Dimensions
Nominal Capacity (Gallons)	50	Weight (lbs.)	165
Rated Storage Capacity	48-Gallon	Width (Inches)	22
Vent Diameter(s)	3-in	Family Size	6
Depth (Inches)	22	Water Connection Size	3/4-in
Diameter (Inches)	22	Insulation Thickness (Inches)	2
Height (Inches)	60.75

Features
Point of Use	No	GPH Recovery at 90 Degrees F (Gallons)	43
Emission Rating	Low NOx	High Altitude Model	Yes
Annual Fuel Utilization Efficiency % (Percentage)	0	Installation Location	Closet
Uniform Energy Factor	0.62	Pilot Light Window	Yes
BTU Rating	40000	Pilot Reset Button	Yes
Super High Efficiency	No	Temperature and Pressure Relief Valve	Yes
Grid Capable	No	Water Connection Location	Top
Scale Prevention	No	Water Heater Style	Tall
Foam Insulation	Yes

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

Warranty
Warranty	9-year limited

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

Miscellaneous
UNSPSC	40101800

Check out the Best Selling Water Heaters on Lowes.com

Review

4.5 out of 5

2758 Reviews

93% Recommend this product

Ratings may include incentivized customer reviews.

Read All Reviews

+ 83

What Customers Are Saying

The AO Smith water heater is generally well-received, providing reliable and efficient hot water with quick heating and consistent temperatures. Many customers report the product's good quality and durability, lasting for several years. The 12-year warranty is seen as a valuable feature. However, some customers experienced issues with damaged or defective units, problems with components, and noise during operation. Overall, the water heater appears to be a solid choice for a residential water heater.

Customer review summary generated by AI, including incentivized reviews.

2758 Customer Reviews

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Our hot water heater broke and we needed a new one asap. Lowe's had this in stock and it was installed quickly by our own plumber. So far so good.

Maria MSeptember 3, 2026
From Signature 100 40-Gallon Tall 9-year Warranty 40000-BTU Natural Gas Water Heater Verified Purchaser

Was this Review Helpful ?

Works well and would recommend to friends

Would Recommend

Works well, but I am surprise and disappointed to see the company use plastic connector for 12 years warranty product

SandySeptember 3, 2026
From Signature 100 50-Gallon Tall 12-year Warranty 40000-BTU Natural Gas Water Heater Verified Purchaser

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A.O Smith

Would Recommend

Water get hot real fast

CLEOSeptember 3, 2026
From Signature 100 50-Gallon Tall 12-year Warranty 40000-BTU Natural Gas Water Heater Verified Purchaser

Was this Review Helpful ?

Good, but came with a broken knob on igniter

Would Recommend

Installation was as expected for a water heater until I got to lighting the pilot. You have to push the knob inward to let gas out while you light it. When I did this, I heard no gas come out and the knob got stuck in the depressed position. I opened the assembly to figure out what was going on and found the back of the knob was installed incorrectly or already damaged. Photo attached. Luckily, the old water heater had an identical knob, so I swapped it onto the new one and from there, it was ve...

DIYER6769August 28, 2026
From Signature 100 40-Gallon Tall 9-year Warranty 40000-BTU Natural Gas Water Heater

Was this Review Helpful ?

HOT HOT HOT

Would Recommend

Bought this almost a week ago. Boy it get the water hot. Feels great to take a hot shower. The cold showers were nice with this 100 degree weather. Very pleased with the product.

TonyAugust 26, 2026

From aosmith.com

Great quality

Would Recommend

It’s been a little over a week and it’s working great. Easy to install

Marcosr432August 24, 2026

From aosmith.com

Nice water heater at a decent price.

Would Recommend

I just installed this. As a swap it was not difficult. I switched to flexible steel lines. Previous was hard plumbed which I don't think is allowed any more.

BillInCTAugust 24, 2026

From aosmith.com

leaks

Would Not Recommend

wen you try to return is a hassle on phone for 2h to get some kind of number

Antonio CisnerosAugust 22, 2026
From Signature 100 40-Gallon Tall 9-year Warranty 40000-BTU Natural Gas Water Heater

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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...

Published by the A. O. Smith TeamAugust 26, 2026

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