A.O. Smith Tankless Water Heaters

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Learn More About A.O. Smith ATO-310U-Nacw-sale-badge
A.O. Smith ATO-310U - Residential 190,000 BTU - Natural Gas Tankless Water Heater - Outdoor
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EnergyStar Water Heater. Ultra Low NOx Emissions (SCAQMD Rule 1146.2 Compliant). Ratings: 7.9 GPM at 40° F Rise, 6.2 GPM at 50° F Rise, 5.3 GPM at 60° F Rise, 4.5 GPM at 70° F Rise. 190k Max BTU/h.
Item#: 69996
Model#: ATO-310U-N
Brand: A.O. Smith
$849.00
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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.
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A.O. Smith ATO-310U - Residential 190,000 BTU - Natural Gas Tankless Water Heater - Outdoor
Learn More About A.O. Smith ATO-340H-Nacw-sale-badge
A.O. Smith ATO-340H - Residential 180,000 BTU - Natural Gas Tankless Water Heater - Outdoor
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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#: 69998
Model#: ATO-340H-N
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.
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A.O. Smith ATO-340H - Residential 180,000 BTU - Natural Gas Tankless Water Heater - Outdoor
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A.O. Smith ATO-340H - Residential 180,000 BTU - Liquid Propane Tankless Water Heater - Outdoor
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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#: 69999
Model#: ATO-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.
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A.O. Smith ATO-340H - Residential 180,000 BTU - Liquid Propane Tankless Water Heater - Outdoor
Learn More About A.O. Smith ATO-510U-Nacw-sale-badge
A.O. Smith ATO-510U - Residential 199,000 BTU - Natural Gas Tankless Water Heater - Outdoor
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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#: 70001
Model#: ATO-510U-N
Brand: A.O. Smith
$1,049.00
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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.
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A.O. Smith ATO-510U - Residential 199,000 BTU - Natural Gas Tankless Water Heater - Outdoor
Learn More About A.O. Smith ATI-540P-Pacw-sale-badge
A.O. Smith ATI-540P - Residential 199,000 BTU - Liquid Propane Tankless Water Heater - Indoor
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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#: 76483
Model#: ATI-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.
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A.O. Smith ATI-540P - Residential 199,000 BTU - Liquid Propane Tankless Water Heater - Indoor
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A.O. Smith ATO-540P - Residential 199,000 BTU - Natural Gas Tankless Water Heater - Outdoor
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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#: 76484
Model#: ATO-540P-N
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.
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A.O. Smith ATO-540P - Residential 199,000 BTU - Natural Gas Tankless Water Heater - Outdoor
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A.O. Smith ATO-540P - Residential 199,000 BTU - Liquid Propane Tankless Water Heater - Outdoor
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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.
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A.O. Smith ATO-540P - Residential 199,000 BTU - Liquid Propane Tankless Water Heater - Outdoor
Learn More About A.O. Smith ATI-240HX3-Nacw-sale-badge
A.O. Smith X3 - Residential 160,000 BTU - Natural Gas Tankless Water Heater - Indoor
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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#: 123206
Model#: ATI-240HX3-N
Brand: A.O. Smith
$1,295.00
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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
A.O. Smith X3 - Residential 160,000 BTU - Natural Gas Tankless Water Heater - Indoor
Learn More About A.O. Smith ATI-240HX3-Pacw-sale-badge
A.O. Smith X3 - Residential 160,000 BTU - Liquid Propane Tankless Water Heater - Indoor
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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#: 123207
Model#: ATI-240HX3-P
Brand: A.O. Smith
$1,295.00
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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.
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A.O. Smith X3 - Residential 160,000 BTU - Liquid Propane Tankless Water Heater - Indoor
Learn More About A.O. Smith ATI-340HX3-Nacw-sale-badge
A.O. Smith X3 - Residential 180,000 BTU - Natural Gas Tankless Water Heater - Indoor
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EnergyStar Condensing Water Heater. Ultra-Low NOx (14 ng/J or 20 ppm). Ratings: 8 GPM at 40° F Rise, 6.8 GPM at 50° F Rise, 5.8 GPM at 60° F Rise, 4.9 GPM at 70° F Rise. 180k Max BTU/h.
Item#: 123208
Model#: ATI-340HX3-N
Brand: A.O. Smith
$1,421.00
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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.
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A.O. Smith X3 - Residential 180,000 BTU - Natural Gas Tankless Water Heater - Indoor
Learn More About A.O. Smith ATI-340HX3-Pacw-sale-badge
A.O. Smith X3 - Residential 180,000 BTU - Liquid Propane Tankless Water Heater - Indoor
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EnergyStar Condensing Water Heater. Ultra-Low NOx (14 ng/J or 20 ppm). Ratings: 8 GPM at 40° F Rise, 6.8 GPM at 50° F Rise, 5.8 GPM at 60° F Rise, 4.9 GPM at 70° F Rise. 180k Max BTU/h.
Item#: 123209
Model#: ATI-340HX3-P
Brand: A.O. Smith
$1,421.00
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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.
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A.O. Smith X3 - Residential 180,000 BTU - Liquid Propane Tankless Water Heater - Indoor
Learn More About A.O. Smith ATO-240HX3-Pacw-sale-badge
A.O. Smith X3 - Residential 160,000 BTU - Liquid Propane Tankless Water Heater - Outdoor
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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#: 123225
Model#: ATO-240HX3-P
Brand: A.O. Smith
$1,295.00
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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.
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A.O. Smith X3 - Residential 160,000 BTU - Liquid Propane Tankless Water Heater - Outdoor
Learn More About A.O. Smith ATO-340HX3-Nacw-sale-badge
A.O. Smith X3 - Residential 180,000 BTU - Natural Gas Tankless Water Heater - Outdoor
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EnergyStar Condensing Water Heater. Ultra-Low NOx (14 ng/J or 20 ppm). Ratings: 8 GPM at 40° F Rise, 6.8 GPM at 50° F Rise, 5.8 GPM at 60° F Rise, 4.9 GPM at 70° F Rise. 180k Max BTU/h.
Item#: 123226
Model#: ATO-340HX3-N
Brand: A.O. Smith
$1,421.00
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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.
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A.O. Smith X3 - Residential 180,000 BTU - Natural Gas Tankless Water Heater - Outdoor
Learn More About A.O. Smith ATO-340HX3-Pacw-sale-badge
A.O. Smith X3 - Residential 180,000 BTU - Liquid Propane Tankless Water Heater - Outdoor
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EnergyStar Condensing Water Heater. Ultra-Low NOx (14 ng/J or 20 ppm). Ratings: 8 GPM at 40° F Rise, 6.8 GPM at 50° F Rise, 5.8 GPM at 60° F Rise, 4.9 GPM at 70° F Rise. 180k Max BTU/h.
Item#: 123227
Model#: ATO-340HX3-P
Brand: A.O. Smith
$1,421.00
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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.
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A.O. Smith X3 - Residential 180,000 BTU - Liquid Propane Tankless Water Heater - Outdoor
Learn More About A.O. Smith ATO-540HX3-Pacw-sale-badge
A.O. Smith X3 - Residential 199,000 BTU - Liquid Propane Tankless Water Heater - Outdoor
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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#: 123229
Model#: ATO-540HX3-P
Brand: A.O. Smith
$1,558.00
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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.
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A.O. Smith X3 - Residential 199,000 BTU - Liquid Propane Tankless Water Heater - Outdoor
Learn More About A.O. Smith ATHR-160Macw-sale-badge
A.O. Smith Adapt™ - Residential 160,000 BTU - Natural Gas Tankless Water Heater - Indoor
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EnergyStar Condensing Water Heater. Ultra-Low NOx Emissions (14 ng/J or 20 PPM). Ratings: 7.5 GPM at 40° F Rise, 6 GPM at 50° F Rise, 5.1 GPM at 60° F Rise, 4.3 GPM at 70° F Rise. 160k BTU/h.
Item#: 154111
Model#: ATHR-160M
Brand: A.O. Smith
$5,345.71
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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.
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.
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A.O. Smith Adapt™ - Residential 160,000 BTU - Natural Gas Tankless Water Heater - Indoor
Learn More About A.O. Smith ATHR-180Macw-sale-badge
A.O. Smith Adapt™ - Residential 180,000 BTU - Natural Gas Tankless Water Heater - Indoor
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EnergyStar Condensing Water Heater. Ultra-Low NOx Emissions (14 ng/J or 20 PPM). Ratings: 8.5 GPM at 40° F Rise, 6.8 GPM at 50° F Rise, 5.8 GPM at 60° F Rise, 4.9 GPM at 70° F Rise. 180k BTU/h.
Item#: 154112
Model#: ATHR-180M
Brand: A.O. Smith
$5,945.71
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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.
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.
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A.O. Smith Adapt™ - Residential 180,000 BTU - Natural Gas Tankless Water Heater - Indoor
Learn More About A.O. Smith ATHR-199Macw-sale-badge
A.O. Smith Adapt™ - Residential 199,000 BTU - Natural Gas Tankless Water Heater - Indoor
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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#: 154113
Model#: ATHR-199M
Brand: A.O. Smith
$6,574.29
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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.
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.
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A.O. Smith Adapt™ - Residential 199,000 BTU - Natural Gas Tankless Water Heater - Indoor
Learn More About A.O. Smith ATHR-160X3acw-sale-badge
A.O. Smith Adapt™ with X3® Scale Prevention - Residential 160,000 BTU - Natural Gas Tankless Water Heater - Indoor
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EnergyStar Condensing Water Heater. Ultra-Low NOx Emissions (14 ng/J or 20 PPM). Ratings: 7.5 GPM at 40° F Rise, 6 GPM at 50° F Rise, 5.1 GPM at 60° F Rise, 4.3 GPM at 70° F Rise. 160k BTU/h.
Item#: 154114
Model#: ATHR-160X3
Brand: A.O. Smith
$5,922.86
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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.
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.
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A.O. Smith Adapt™ with X3® Scale Prevention - Residential 160,000 BTU - Natural Gas Tankless Water Heater - Indoor
Learn More About A.O. Smith ATHR-180X3acw-sale-badge
A.O. Smith Adapt™ with X3® Scale Prevention - Residential 180,000 BTU - Natural Gas Tankless Water Heater - Indoor
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EnergyStar Condensing Water Heater. Ultra-Low NOx Emissions (14 ng/J or 20 PPM). Ratings: 8.5 GPM at 40° F Rise, 6.8 GPM at 50° F Rise, 5.8 GPM at 60° F Rise, 4.9 GPM at 70° F Rise. 180k BTU/h.
Item#: 154115
Model#: ATHR-180X3
Brand: A.O. Smith
$6,525.71
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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.
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.
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A.O. Smith Adapt™ with X3® Scale Prevention - Residential 180,000 BTU - Natural Gas Tankless Water Heater - Indoor