Name: A.O. Smith Signature 100 40-Gallon Short 6-year Warranty 38000-BTU Direct Vent Natural Gas Water Heater
Brand: A.O. Smith
SKU: 1000213695
Price: 1249 USD
Availability: InStock
Rating: 4.1 (51 reviews)

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A. O. Smith's Signature 100 Series 40-Gallon Short Low NOx Direct Vent Natural Gas Water Heater is designed to provide efficient and reliable hot water for households with 3 to 4 people when sized appropriately. With an environmentally friendly 38,000 BTU Low NOx gas burner, this natural gas water heater delivers 64 gallons of hot water in the first hour. It has an electronic gas valve that provides precise temperature control for optimum hot water delivery without the need for an external power source. For your convenience, the gas valve also includes an LED status indicator for diagnostics reporting and a push button ignition to simplify the startup process. A. O. Smith's 40-gallon natural gas water heater is designed with your safety in mind. With a built-in safety system, this model reduces the risk of accidental flammable vapor ignitions. A factory-installed temperature and pressure relief valve and tamper-proof drain valve also ensures 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 6-year limited warranty to give you additional peace of mind. Call 1-877-GOLowes to get this water heater installed.

Delivers the ideal amount of hot water for households with 3 to 4 people when sized appropriately
Features an environmentally-friendly 38,000 BTU low NOx 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
Short 49.75-in H x 22-in diameter design is ideal for condensed spaces like under staircases and closet installations
Direct vent installs through side wall
High-altitude certified from 0 ft to 7,700 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	Direct
Vent Type	Concentric

Dimensions
Nominal Capacity (Gallons)	40	Weight (lbs.)	178
Rated Storage Capacity	39-Gallon	Width (Inches)	24
Vent Diameter(s)	Concentric 3-in to 6-in	Family Size	4
Depth (Inches)	22	Water Connection Size	3/4-in
Diameter (Inches)	22	Insulation Thickness (Inches)	2
Height (Inches)	49.75

Features
Point of Use	No	GPH Recovery at 90 Degrees F (Gallons)	41
Emission Rating	Low NOx	High Altitude Model	Yes
Annual Fuel Utilization Efficiency % (Percentage)	0	Installation Location	N/A (Portable)
Uniform Energy Factor	0.60	Pilot Light Window	Yes
BTU Rating	38000	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	Short
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

4.1 out of 5

51 Reviews

2 Star

74% Recommend this product

Ratings may include incentivized customer reviews.

+ 3

What Customers Are Saying

This water heater has mixed reviews. On the positive side, it is reported to heat up quickly, be energy-efficient, and have a reliable brand history. The direct vent feature is praised for improving safety. However, some customers received damaged or defective units and struggled with the installation process, particularly the venting components. The overall quality control and customer service seem inconsistent, leading to frustrating experiences for some buyers.

Customer review summary generated by AI, including incentivized reviews.

51 Customer Reviews

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Easy install and gets the job done

Would Recommend

Heats my water as I need it to.

DDubsMay 18, 2026
From Signature 100 50-Gallon Tall 6-year Warranty 40000-BTU Direct Vent Natural Gas Water Heater Verified Purchaser

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Easy install

Would Recommend

JctacApril 16, 2026
From Signature 100 50-Gallon Tall 6-year Warranty 40000-BTU Direct Vent Natural Gas Water Heater Verified Purchaser

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Too many things wrong

Would Not Recommend

It took me some efforts to have it fixed and brought back to what it is supposed to be like from the factory, apparently sloppy assembly at the manufacturer facility is quite acceptable there. First of all the vent was not assembled straight and I needed to correct this issue by myself and might have been a major issue in the future if I left it unattended due to possible separation of exhaust pipe from the manifold. See before and after pictures below. Second major complaint I have is how gas l...

AndriyKoFebruary 16, 2026
From Signature 100 50-Gallon Tall 6-year Warranty 40000-BTU Direct Vent Natural Gas Water Heater Verified Purchaser

https://photos-us.bazaarvoice.com/photo/2/cGhvdG86bG93ZXM/83bb39a3-9801-5c3b-b45a-0040b7597662

https://photos-us.bazaarvoice.com/photo/2/cGhvdG86bG93ZXM/203da1d5-bb01-541f-9d10-a8b1d1c64bad

https://photos-us.bazaarvoice.com/photo/2/cGhvdG86bG93ZXM/fec4daf5-aac6-5242-92a6-b36cf15d5e3f

https://photos-us.bazaarvoice.com/photo/2/cGhvdG86bG93ZXM/ec729dce-de86-5007-85d0-d4437f38a9e7

https://photos-us.bazaarvoice.com/photo/2/cGhvdG86bG93ZXM/0f296cf7-e4cf-5ebe-9458-9bb611d0c244

https://photos-us.bazaarvoice.com/photo/2/cGhvdG86bG93ZXM/790bbb79-5b33-59ec-ac5b-21daa520f91f

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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...

Published by the A. O. Smith TeamFebruary 17, 2026

Have a helper tank is heavy by yourself

Would Recommend

Works well no issues easy install

KokaDecember 24, 2025
From Signature 100 50-Gallon Tall 6-year Warranty 40000-BTU Direct Vent Natural Gas Water Heater Verified Purchaser

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Heat the water very quick

Would Recommend

Had this water heater for 1 year ,and I'm pleased with it

JazzJune 17, 2025

From aosmith.com

Better products

Would Recommend

More technology

Mr CFebruary 27, 2025
Verified Purchaser

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Check the unit in the store before you buy it!

Would Not Recommend

Product is ok, but how Lowe’s is handling the product. I bought 2 of them from Lowe’s. The first one had to dense on the outside, they installed it, next day it was leaking on the bottom. The second one, I opened the box, the water heater looks like someone trough it from the truck, the hole side was flatted, several dense around the unit. Never buy it again from Lowe’s.

DeitreDecember 18, 2024
From Signature 100 50-Gallon Tall 6-year Warranty 40000-BTU Direct Vent Natural Gas Water Heater Verified Purchaser

https://photos-us.bazaarvoice.com/photo/2/cGhvdG86bG93ZXM/a742f2ad-d88b-571e-ba59-5ba863f42798

https://photos-us.bazaarvoice.com/photo/2/cGhvdG86bG93ZXM/b5415d33-1282-5b68-986a-8dd036ce07e2

https://photos-us.bazaarvoice.com/photo/2/cGhvdG86bG93ZXM/bbad7221-e317-59bd-9c75-e0801b46e4b4

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Response from Published by the A. O. Smith Team

We are very 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 TeamDecember 26, 2024

Beware of dents. Fully inspect upon delivery.

The overall functionality of the tank is good. Unfortunately the outside casing was damaged with several dents. Still waiting follow-up and resolution from store management team.

Customer of water tankNovember 6, 2024
From Signature 100 50-Gallon Tall 6-year Warranty 40000-BTU Direct Vent Natural Gas Water Heater Verified Purchaser

https://photos-us.bazaarvoice.com/photo/2/cGhvdG86bG93ZXM/ebc3adb6-6c57-5fd0-821f-4f5f95496069

https://photos-us.bazaarvoice.com/photo/2/cGhvdG86bG93ZXM/78dddf6f-52a9-5074-a6c8-2b738036abf8

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