Takagi T-T1-OS-NG Outdoor Commercial Tankless Water Heater

Model T-T1-OS-NG
4.2/5 from 60 ratings
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Price as of May 2026
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Btu
199000
Venting
Outdoor — no venting
Fuel Type
Natural Gas
Tank Type
Tankless
Capacity Gpm
10
Energy Factor
0.94

Takagi T-T1-OS-NG Outdoor Commercial Tankless Water Heater Review

The Takagi T-T1-OS-NG is an outdoor commercial tankless water heater. "T-T1" identifies the smaller commercial platform; "OS-NG" means outdoor sealed natural gas.

Specs: 199,000 BTU natural gas input, UEF 0.95 condensing, 11.0 GPM at a 35°F rise, dual stainless heat exchanger. Sealed direct-vent exterior mounting. 12-year warranty on heat exchanger.

The outdoor commercial configuration serves light commercial applications in warm-climate markets. Eliminates indoor venting cost for commercial installs that can use exterior wall mounting.

About $2,900 unit, $4,400 installed. Right buyer: light commercial application in warm-climate region with exterior wall mount location.

Full Specifications

Brand
Takagi
Model Number
T-T1-OS-NG
Btu
199000
Venting
Outdoor — no venting
Fuel Type
Natural Gas
Tank Type
Tankless
Capacity Gpm
10
Energy Factor
0.94
Warranty Years
10

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