Takagi T-D2-OS-NG Outdoor Condensing Tankless Water Heater
Takagi T-D2-OS-NG Outdoor Condensing Tankless Water Heater Review
The Takagi T-D2-OS-NG is the outdoor variant of Takagi's T-D2 condensing tankless platform. "T-D2" identifies the dual-flow condensing series; "OS-NG" means outdoor sealed natural gas.
Specs: 199,000 BTU natural gas input, UEF 0.95 condensing, 10.0 GPM at a 35°F rise, dual stainless heat exchanger. Sealed direct-vent exterior mounting. 15-year warranty on heat exchanger.
The outdoor T-D2 is Takagi's flagship outdoor condensing tankless. Same engineering as Rheem RTGH-95XLN at Home Depot. The outdoor configuration eliminates indoor venting cost in warm-climate markets where exterior install is code-acceptable.
About $2,200 unit, $3,400 installed. Right buyer: warm-climate primary residence with exterior wall mount location wanting Takagi/Rheem engineering.
- Outdoor mounting — eliminates indoor venting cost ($500–1,500 savings) and frees mechanical room space
- UEF 0.95 — top-tier efficiency; qualifies for Inflation Reduction Act §25C residential credit
- 15-year warranty — top-tier coverage for residential water heaters
- High 10 GPM output — serves 3+ simultaneous hot-water fixtures in most US climates
- Requires dedicated 199K BTU gas supply line — undersized gas piping is the leading cause of flow-rate shortfalls