Name: A.O. Smith Signature 100 40-Gallons Tall 6-year Warranty 35500-BTU Natural Gas Water Heater
Brand: A.O. Smith
SKU: 1002550492
Price: 629 USD
Availability: InStock
Rating: 4.5 (3671 reviews)

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Install this A. O. Smith Signature 100 Series atmospheric vent 40-gallon natural gas water heater in narrow spaces to preserve room in your home. Designed to provide efficient, reliable hot water for 3 to 4-person households when appropriately sized, this low NOx water heater features an environmentally friendly 35,500 BTU gas burner that delivers 65 gallons of hot water the first hour. The electronic gas valve not only ensures precise temperature control for optimum hot water delivery, and it also has an LED status indicator for easy diagnostics reporting and a push-button ignition to simplify the startup process. This A. O. Smith gas hot water heater has a built-in safety system that decreases the risk of accidental flammable vapor ignition. For added safety, this model also includes a factory-installed temperature and pressure relief valve and tamper-proof drain valve. 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 6-year limited warranty for extra peace of mind. Call 1-877-GOLowes to get this water heater installed same day.

Delivers the ideal amount of hot water for households with 3 to 4 people when sized appropriately
Features an environmentally friendly 35,500 BTU Low NOx burner that delivers 65 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 61.75-in H x 20-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 6-year limited tank and parts guarantee and a 1-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)	40	Weight (lbs.)	135.75
Rated Storage Capacity	38-Gallon	Width (Inches)	20
Vent Diameter(s)	3-in; 4-in	Family Size	4
Depth (Inches)	23.75	Water Connection Size	3/4-in
Diameter (Inches)	20	Insulation Thickness (Inches)	2
Height (Inches)	61.81

Features
Point of Use	No	GPH Recovery at 90 Degrees F (Gallons)	38
Emission Rating	Low NOx	High Altitude Model	Yes
Annual Fuel Utilization Efficiency % (Percentage)	0	Pilot Light Window	Yes
Uniform Energy Factor	.59	Pilot Reset Button	Yes
BTU Rating	35500	Temperature and Pressure Relief Valve	Yes
Super High Efficiency	No	Water Connection Location	Top
Grid Capable	No	Water Heater Style	Tall
Scale Prevention	No	Leak Detection	No
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	6-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

3671 Reviews

92% Recommend this product

Ratings may include incentivized customer reviews.

Read All Reviews

+ 82

What Customers Are Saying

The AO Smith gas water heater is reported to be a reliable and high-quality product. Customers praise its easy installation, quick hot water delivery, and convenient electronic ignition and status light features. The product is noted for its durability, with some units lasting over 10 years. While a few customers experienced minor issues, the majority of reviews are very positive about the water heater's performance, value, and ease of use.

Customer review summary generated by AI, including incentivized reviews.

3671 Customer Reviews

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Absolute Junk

Would Not Recommend

Bought this unit a little over 2 years ago. Performed well until about a month ago. Thermopile failed. Part was under warranty, labor was not. Cost $300 in labor to have replaced with an AO Smith thermopile. New thermopile failed within 1 month of replacement.

O2BN910August 23, 2026
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...

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

Great

So far it's working great

Kp20August 22, 2026
Verified Purchaser

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Great Installation - High end cost

It is too earlier to speak about the quality of the product. But, the installation and total cost are another matter. Note - Lowes hands the estimate, installation and billing to a licensed plumber. The only selection for me was Rescue Rooter. The actual installation was great. The Rescue Rooter Technician was friendly, considerate and efficient. On the other hand, the cost was higher than I expected by about $400. I accepted it due to the urgency of replacing a leaking water tank. Checking...

JackAugust 22, 2026

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Response from Published by the A. O. Smith Team

We are sorry to hear of your experience.

We recommend reaching out to Lowe's Customer Care at 1-800-445-6937 or Text 84109.

Published by the A. O. Smith TeamAugust 27, 2026

Would Recommend

They were friendly and quick! They deserve 10 stars!

DreaAugust 21, 2026
From Signature 100 50-Gallons Tall 6-year Warranty 40000-BTU Natural Gas Water Heater

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