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A.O. Smith Tankless Water Heaters

45 Products
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Fuel Type Learn More
Fuel Type
To create heat, some form of fuel is required. Fuel Type specifies what the product uses as an input to create heat.
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Uniform Energy Factor Learn More
Uniform Energy Factor
Uniform Energy Factor (UEF) is a measurement of water heater energy efficiency. The higher the energy factor, the more efficient the water heater.
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Vent Type Learn More
Vent Type
Products that use combustion (burning) of fuel to create heat also create potentially dangerous gasses that need to be exhausted (AKA "Vented"). Depending on the product, venting can be done via a chimney, through a side wall, or use a second vent to provide fresh air to the appliance.
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Installation Location
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Flow Rate at 40F Temperature Rise (GPM) Learn More
Flow Rate at 40F Temperature Rise (GPM)
Flow rate measures how much hot water your heater can deliver. Click Learn More to determine the appropriate temperature rise to use based on your location.
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Flow Rate at 50F Temperature Rise (GPM) Learn More
Flow Rate at 50F Temperature Rise (GPM)
Flow rate measures how much hot water your heater can deliver. Click Learn More to determine the appropriate temperature rise to use based on your location.
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Flow Rate at 60F Temperature Rise (GPM) Learn More
Flow Rate at 60F Temperature Rise (GPM)
Flow rate measures how much hot water your heater can deliver. Click Learn More to determine the appropriate temperature rise to use based on your location.
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Flow Rate at 70F Temperature Rise (GPM) Learn More
Flow Rate at 70F Temperature Rise (GPM)
Flow rate measures how much hot water your heater can deliver. Click Learn More to determine the appropriate temperature rise to use based on your location.
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Product Width (Inches)
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Product Height (Inches)
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Includes Pump
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Price
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Maximum Input Capacity (BTU) Learn More
Maximum Input Capacity (BTU)
The Maximum Input Capacity describes how quickly the appliance will use fuel when delivering it's maximum capacity. The units may change depending on the fuel being used.
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Product Line
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Product Depth (Inches)
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EnergyStar Condensing Water Heater. Ultra-Low NOx (14 ng/J or 20 ppm). Ratings: 6.7 GPM at 40° F Rise, 6.1 GPM at 50° F Rise, 5.1 GPM at 60° F Rise, 4.3 GPM at 70° F Rise. 160k Max BTU/h.
Item#: 157489
Brand: A.O. Smith
Originally $1,453.00$1,089.75
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*This product qualifies for Free Shipping anywhere in the contiguous US. Accessories may ship separately. Items over 100lbs shipped via semi-truck, be sure to select "Lift Gate" to lower the product to the ground curbside. Remote area surcharges map apply, see our full shipping policy for more details.
Only 1 In-Stock
EnergyStar Condensing Water Heater. Ultra-Low NOx Emissions (14 ng/J or 20 PPM). Ratings: 9.6 GPM at 40° F Rise, 7.6 GPM at 50° F Rise, 6.3 GPM at 60° F Rise, 5.3 GPM at 70° F Rise. 199k BTU/h.
Item#: 154116
Model#: ATHR-199X3
Brand: A.O. Smith
Originally $2,233.46$1,936.00
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Free Shipping
*This product qualifies for Free Shipping anywhere in the contiguous US. Accessories may ship separately. Items over 100lbs shipped via semi-truck, be sure to select "Lift Gate" to lower the product to the ground curbside. Remote area surcharges map apply, see our full shipping policy for more details.
Free Lift Gate
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Free Lift Gate
*This product qualifies for Free Lift Gate Service. Items over 100lbs normally ship via semi-truck. Select this service if you need the product lowered to the ground curbside. To learn more about Lift Gate Service, read our shipping policy.
In-Stock
EnergyStar Condensing Water Heater. Ultra-Low NOx (14 ng/J or 20 ppm). Ratings: 9.5 GPM at 40° F Rise, 7.5 GPM at 50° F Rise, 6.3 GPM at 60° F Rise, 5.4 GPM at 70° F Rise. 199k Max BTU/h.
Item#: 61571
Model#: ATI-540H-N
Brand: A.O. Smith
$1,269.00
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*This product qualifies for Free Shipping anywhere in the contiguous US. Accessories may ship separately. Items over 100lbs shipped via semi-truck, be sure to select "Lift Gate" to lower the product to the ground curbside. Remote area surcharges map apply, see our full shipping policy for more details.
In-Stock
EnergyStar Condensing Water Heater. Low NOx Emissions (< 40 ng/J or 55 PPM). Ratings: 8.0 GPM at 40° F Rise, 6.8 GPM at 50° F Rise, 5.7 GPM at 60° F Rise, 4.8 GPM at 70° F Rise. 171k Effective BTU/h.
Item#: 61570
Model#: ATI-340H-N
Brand: A.O. Smith
$1,142.00
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Free Shipping
*This product qualifies for Free Shipping anywhere in the contiguous US. Accessories may ship separately. Items over 100lbs shipped via semi-truck, be sure to select "Lift Gate" to lower the product to the ground curbside. Remote area surcharges map apply, see our full shipping policy for more details.
Factory-Direct
EnergyStar Condensing Water Heater. Ultra-Low NOx (14 ng/J or 20 ppm). Ratings: 9.5 GPM at 40° F Rise, 7.5 GPM at 50° F Rise, 6.3 GPM at 60° F Rise, 5.4 GPM at 70° F Rise. 199k Max BTU/h.
Item#: 76482
Model#: ATI-540P-N
Brand: A.O. Smith
$1,501.00
Free Shipping
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Free Shipping
*This product qualifies for Free Shipping anywhere in the contiguous US. Accessories may ship separately. Items over 100lbs shipped via semi-truck, be sure to select "Lift Gate" to lower the product to the ground curbside. Remote area surcharges map apply, see our full shipping policy for more details.
In-Stock
EnergyStar Condensing Water Heater. Low NOx Emissions (< 40 ng/J or 55 PPM). Ratings: 9.5 GPM at 40° F Rise, 7.5 GPM at 50° F Rise, 6.3 GPM at 60° F Rise, 5.4 GPM at 70° F Rise. 189k Effective BTU/h.
Item#: 61569
Model#: ATO-540H-P
Brand: A.O. Smith
$1,269.00
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Free Shipping
*This product qualifies for Free Shipping anywhere in the contiguous US. Accessories may ship separately. Items over 100lbs shipped via semi-truck, be sure to select "Lift Gate" to lower the product to the ground curbside. Remote area surcharges map apply, see our full shipping policy for more details.
In-Stock
EnergyStar Condensing Water Heater. Low NOx Emissions (< 40 ng/J or 55 PPM). Ratings: 9.5 GPM at 40° F Rise, 7.5 GPM at 50° F Rise, 6.3 GPM at 60° F Rise, 5.4 GPM at 70° F Rise. 199k Effective BTU/h.
Item#: 76485
Model#: ATO-540P-P
Brand: A.O. Smith
$1,501.00
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*This product qualifies for Free Shipping anywhere in the contiguous US. Accessories may ship separately. Items over 100lbs shipped via semi-truck, be sure to select "Lift Gate" to lower the product to the ground curbside. Remote area surcharges map apply, see our full shipping policy for more details.
Factory-Direct
EnergyStar Condensing Water Heater. Ultra-Low NOx (14 ng/J or 20 ppm). Ratings: 9.5 GPM at 40° F Rise, 7.5 GPM at 50° F Rise, 6.2 GPM at 60° F Rise, 5.2 GPM at 70° F Rise. 199k Max BTU/h.
Item#: 123228
Model#: ATO-540HX3-N
Brand: A.O. Smith
$1,558.00
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Free Shipping
*This product qualifies for Free Shipping anywhere in the contiguous US. Accessories may ship separately. Items over 100lbs shipped via semi-truck, be sure to select "Lift Gate" to lower the product to the ground curbside. Remote area surcharges map apply, see our full shipping policy for more details.
Factory-Direct
EnergyStar Condensing Water Heater. Ultra-Low NOx (14 ng/J or 20 ppm). Ratings: 9.5 GPM at 40° F Rise, 7.5 GPM at 50° F Rise, 6.3 GPM at 60° F Rise, 5.4 GPM at 70° F Rise. 199k Max BTU/h.
Item#: 61568
Model#: ATI-540H-P
Brand: A.O. Smith
$1,394.00
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*This product qualifies for Free Shipping anywhere in the contiguous US. Accessories may ship separately. Items over 100lbs shipped via semi-truck, be sure to select "Lift Gate" to lower the product to the ground curbside. Remote area surcharges map apply, see our full shipping policy for more details.
Factory-Direct
EnergyStar Water Heater. Ultra Low NOx Emissions (SCAQMD Rule 1146.2 Compliant). Ratings: 8.3 GPM at 40° F Rise, 6.9 GPM at 50° F Rise, 5.5 GPM at 60° F Rise, 4.8 GPM at 70° F Rise. 199k Max BTU/h.
Item#: 69986
Model#: ATI-510U-N
Brand: A.O. Smith
$1,059.00
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*This product qualifies for Free Shipping anywhere in the contiguous US. Accessories may ship separately. Items over 100lbs shipped via semi-truck, be sure to select "Lift Gate" to lower the product to the ground curbside. Remote area surcharges map apply, see our full shipping policy for more details.
Factory-Direct
EnergyStar Condensing Water Heater. Low NOx Emissions (< 40 ng/J or 55 PPM). Ratings: 9.5 GPM at 40° F Rise, 7.5 GPM at 50° F Rise, 6.3 GPM at 60° F Rise, 5.4 GPM at 70° F Rise. 189k Effective BTU/h.
Item#: 70002
Model#: ATO-540H-N
Brand: A.O. Smith
$1,269.00
Free Shipping
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Free Shipping
*This product qualifies for Free Shipping anywhere in the contiguous US. Accessories may ship separately. Items over 100lbs shipped via semi-truck, be sure to select "Lift Gate" to lower the product to the ground curbside. Remote area surcharges map apply, see our full shipping policy for more details.
Factory-Direct
EnergyStar Condensing Water Heater. Ultra-Low NOx (14 ng/J or 20 ppm). Ratings: 9.5 GPM at 40° F Rise, 7.5 GPM at 50° F Rise, 6.2 GPM at 60° F Rise, 5.2 GPM at 70° F Rise. 199k Max BTU/h.
Item#: 123211
Model#: ATI-540HX3-P
Brand: A.O. Smith
$1,686.00
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*This product qualifies for Free Shipping anywhere in the contiguous US. Accessories may ship separately. Items over 100lbs shipped via semi-truck, be sure to select "Lift Gate" to lower the product to the ground curbside. Remote area surcharges map apply, see our full shipping policy for more details.
Factory-Direct
EnergyStar Condensing Water Heater. Low NOx Emissions (< 40 ng/J or 55 PPM). Ratings: 6.7 GPM at 40° F Rise, 6.1 GPM at 50° F Rise, 5.0 GPM at 60° F Rise, 4.3 GPM at 70° F Rise. 152k Effective BTU/h.
Item#: 61572
Model#: ATI-240H-N
Brand: A.O. Smith
$1,022.00
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Free Shipping
*This product qualifies for Free Shipping anywhere in the contiguous US. Accessories may ship separately. Items over 100lbs shipped via semi-truck, be sure to select "Lift Gate" to lower the product to the ground curbside. Remote area surcharges map apply, see our full shipping policy for more details.
Factory-Direct
EnergyStar Condensing Water Heater. Low NOx Emissions (< 40 ng/J or 55 PPM). Ratings: 5.4 GPM at 40° F Rise, 4.4 GPM at 50° F Rise, 3.8 GPM at 60° F Rise, 3.2 GPM at 70° F Rise. 112k Effective BTU/h.
Item#: 61575
Model#: ATI-140H-N
Brand: A.O. Smith
$845.00
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*This product qualifies for Free Shipping anywhere in the contiguous US. Accessories may ship separately. Items over 100lbs shipped via semi-truck, be sure to select "Lift Gate" to lower the product to the ground curbside. Remote area surcharges map apply, see our full shipping policy for more details.
Factory-Direct
EnergyStar Water Heater. Ultra Low NOx Emissions (SCAQMD Rule 1146.2 Compliant). Ratings: 5.8 GPM at 40° F Rise, 4.5 GPM at 50° F Rise, 3.9 GPM at 60° F Rise, 3.3 GPM at 70° F Rise. 140k Effective BTU/h.
Item#: 69978
Model#: ATI-110U-N
Brand: A.O. Smith
$845.00
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*This product qualifies for Free Shipping anywhere in the contiguous US. Accessories may ship separately. Items over 100lbs shipped via semi-truck, be sure to select "Lift Gate" to lower the product to the ground curbside. Remote area surcharges map apply, see our full shipping policy for more details.
Factory-Direct
EnergyStar Condensing Water Heater. Low NOx Emissions (< 40 ng/J or 55 PPM). Ratings: 5.4 GPM at 40° F Rise, 4.4 GPM at 50° F Rise, 3.8 GPM at 60° F Rise, 3.2 GPM at 70° F Rise. 112k Effective BTU/h.
Item#: 69979
Model#: ATI-140H-P
Brand: A.O. Smith
$845.00
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*This product qualifies for Free Shipping anywhere in the contiguous US. Accessories may ship separately. Items over 100lbs shipped via semi-truck, be sure to select "Lift Gate" to lower the product to the ground curbside. Remote area surcharges map apply, see our full shipping policy for more details.
Factory-Direct
EnergyStar Condensing Water Heater. Low NOx Emissions (< 40 ng/J or 55 PPM). Ratings: 6.7 GPM at 40° F Rise, 6.1 GPM at 50° F Rise, 5.0 GPM at 60° F Rise, 4.3 GPM at 70° F Rise. 152k Effective BTU/h.
Item#: 69980
Model#: ATI-240H-P
Brand: A.O. Smith
$1,022.00
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*This product qualifies for Free Shipping anywhere in the contiguous US. Accessories may ship separately. Items over 100lbs shipped via semi-truck, be sure to select "Lift Gate" to lower the product to the ground curbside. Remote area surcharges map apply, see our full shipping policy for more details.
Factory-Direct
$981.00
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*This product qualifies for Free Shipping anywhere in the contiguous US. Accessories may ship separately. Items over 100lbs shipped via semi-truck, be sure to select "Lift Gate" to lower the product to the ground curbside. Remote area surcharges map apply, see our full shipping policy for more details.
Factory-Direct
EnergyStar Condensing Water Heater. Low NOx Emissions (< 40 ng/J or 55 PPM). Ratings: 8.0 GPM at 40° F Rise, 6.8 GPM at 50° F Rise, 5.7 GPM at 60° F Rise, 4.8 GPM at 70° F Rise. 171k Effective BTU/h.
Item#: 69983
Model#: ATI-340H-P
Brand: A.O. Smith
$1,142.00
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*This product qualifies for Free Shipping anywhere in the contiguous US. Accessories may ship separately. Items over 100lbs shipped via semi-truck, be sure to select "Lift Gate" to lower the product to the ground curbside. Remote area surcharges map apply, see our full shipping policy for more details.
Factory-Direct
$1,160.00
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*This product qualifies for Free Shipping anywhere in the contiguous US. Accessories may ship separately. Items over 100lbs shipped via semi-truck, be sure to select "Lift Gate" to lower the product to the ground curbside. Remote area surcharges map apply, see our full shipping policy for more details.
Factory-Direct
EnergyStar Condensing Water Heater. Low NOx Emissions (< 40 ng/J or 55 PPM). Ratings: 5.4 GPM at 40° F Rise, 4.4 GPM at 50° F Rise, 3.8 GPM at 60° F Rise, 3.2 GPM at 70° F Rise. 112k Effective BTU/h.
Item#: 69991
Model#: ATO-140H-N
Brand: A.O. Smith
$845.00
Free Shipping
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*This product qualifies for Free Shipping anywhere in the contiguous US. Accessories may ship separately. Items over 100lbs shipped via semi-truck, be sure to select "Lift Gate" to lower the product to the ground curbside. Remote area surcharges map apply, see our full shipping policy for more details.
Factory-Direct
EnergyStar Condensing Water Heater. Low NOx Emissions (< 40 ng/J or 55 PPM). Ratings: 5.4 GPM at 40° F Rise, 4.4 GPM at 50° F Rise, 3.8 GPM at 60° F Rise, 3.2 GPM at 70° F Rise. 112k Effective BTU/h.
Item#: 69992
Model#: ATO-140H-P
Brand: A.O. Smith
$845.00
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*This product qualifies for Free Shipping anywhere in the contiguous US. Accessories may ship separately. Items over 100lbs shipped via semi-truck, be sure to select "Lift Gate" to lower the product to the ground curbside. Remote area surcharges map apply, see our full shipping policy for more details.
Factory-Direct
EnergyStar Condensing Water Heater. Low NOx Emissions (< 40 ng/J or 55 PPM). Ratings: 6.7 GPM at 40° F Rise, 6.1 GPM at 50° F Rise, 5.0 GPM at 60° F Rise, 4.3 GPM at 70° F Rise. 171k Effective BTU/h.
Item#: 69993
Model#: ATO-240H-N
Brand: A.O. Smith
$1,022.00
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*This product qualifies for Free Shipping anywhere in the contiguous US. Accessories may ship separately. Items over 100lbs shipped via semi-truck, be sure to select "Lift Gate" to lower the product to the ground curbside. Remote area surcharges map apply, see our full shipping policy for more details.
In-Stock
EnergyStar Condensing Water Heater. Low NOx Emissions (< 40 ng/J or 55 PPM). Ratings: 6.7 GPM at 40° F Rise, 6.1 GPM at 50° F Rise, 5.0 GPM at 60° F Rise, 4.3 GPM at 70° F Rise. 171k Effective BTU/h.
Item#: 69994
Model#: ATO-240H-P
Brand: A.O. Smith
$1,022.00
Free Shipping
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Free Shipping
*This product qualifies for Free Shipping anywhere in the contiguous US. Accessories may ship separately. Items over 100lbs shipped via semi-truck, be sure to select "Lift Gate" to lower the product to the ground curbside. Remote area surcharges map apply, see our full shipping policy for more details.
Factory-Direct