Bosch Greentherm 9000 Outdoor Tankless Water Heater

Model WTG-9000-OD-NG
4.3/5 from 140 ratings
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Price as of Apr 2026
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Btu
199000
Venting
Outdoor — no venting
Fuel Type
Natural Gas
Tank Type
Tankless
Capacity Gpm
9.9
Energy Factor
0.94

Bosch Greentherm 9000 Outdoor Tankless Water Heater Review

The Bosch Greentherm 9000 Outdoor Tankless Water Heater is Bosch's premium outdoor condensing tankless. Exterior wall-mount configuration eliminates indoor venting.

Specs: 199,000 BTU natural gas input, UEF 0.94 condensing, 9.0 GPM at a 35°F rise, stainless steel heat exchanger. Sealed direct-vent exterior mounting. 15-year warranty on heat exchanger.

The Greentherm 9000 Outdoor is Bosch's flagship outdoor tankless. German engineering with acoustic refinement and smooth modulation. UEF 0.94 is competitive with Rinnai V94eN and Navien NPE-A outdoor variants.

About $2,400 unit, $3,500 installed. Right buyer: warm-climate primary residence with suitable exterior wall mount location, valuing Bosch engineering. Smaller US service network than Rinnai/Navien outdoor variants.

Full Specifications

Brand
Bosch
Model Number
WTG-9000-OD-NG
Btu
199000
Venting
Outdoor — no venting
Fuel Type
Natural Gas
Tank Type
Tankless
Capacity Gpm
9.9
Energy Factor
0.94
Warranty Years
15

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