Canada-wide gas boiler information · On-site service in Greater Vancouver, BC
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Comparison
Verdict in brief
The T-D2-IN-N and TK-540P-NIH are both 199,000 BTU/h indoor tankless water heaters, but the T-D2 is non-condensing at 0.80 thermal efficiency while the TK-540P is condensing with an integrated recirculation pump at 0.93 UEF. The T-D2 weighs 45 lb; the TK-540P 71 lb and vents on PVC to 100 ft.
Published manufacturer figures. Input and output are kept separate; blanks mean the manufacturer did not publish that value.
| Specification | Takagi T-D2-IN-N | Takagi TK-540P-NIH |
|---|---|---|
| Input, minimum | 11,000 BTU/h | 15,000 BTU/h |
| Input, maximum | 199,000 BTU/h | 199,000 BTU/h |
| Thermal efficiency | 0.8 % | 0.93 UEF |
| Maximum flow rate | 10 GPM | 10 GPM |
| Weight | 45 lb | 71 lb |
| Technology | Non-condensing tankless water heater | Condensing tankless water heater |
| Venting | 4" Category III to 50 equivalent ft; optional direct-vent conversion with 3" intake | Power direct vent: 3" PVC to 70 ft or 4" PVC to 100 ft; PVC/CPVC/ABS solid core |
The T-D2-IN-N and TK-540P-NIH share the same maximum input — 199,000 BTU/h — but represent two technology generations. The T-D2 is a non-condensing unit at 0.80 thermal efficiency with a 11,000 BTU/h minimum, while the TK-540P is a condensing unit at 0.93 UEF (indoor) with a 15,000 BTU/h minimum on natural gas and an integrated recirculation pump.
Venting and installation differ substantially: the T-D2 uses 4" Category III stainless venting to 50 ft, while the TK-540P uses power direct venting in 3" PVC to 70 ft or 4" PVC to 100 ft, with common venting up to 8 units and Easy-Link with up to three other T-H3 units. The TK-540P also carries integrated temperature and pump controls with advanced diagnostics and a factory-installed power cord.
Physically the condensing unit is larger: the TK-540P measures 23-5/8 × 17-3/4 × 11-1/4 in and weighs 71 lb against the T-D2's 20-1/4 × 13-3/4 × 9-1/2 in, 45 lb. Both are domestic-hot-water appliances — neither is a boiler — and the choice usually follows venting material and efficiency targets, since both deliver 10 GPM.
Takagi
The Takagi T-D2-IN-N is a non-condensing tankless water heater — a DHW-only appliance, not a boiler — firing 11,000 to 199,000 BTU/h on natural gas with 0.8% thermal efficiency and up to 10 GPM.
Takagi
The Takagi TK-540P-NIH is a condensing tankless water heater — a DHW-only appliance, not a boiler — firing 15,000 to 199,000 BTU/h on natural gas with 0.93 UEF and up to 10 GPM.
The TK-540P: its specification sheet prints 0.93 UEF indoors (0.95 outdoors), while the T-D2 prints 0.80 thermal efficiency. The condensing TK-540P also vents in PVC rather than Category III stainless.
Both print up to 10 GPM maximum flow, though the T-D2's minimum input is 11,000 BTU/h against the TK-540P's 15,000 BTU/h (natural gas).
Yes. The TK-540P has an integrated recirculation pump and, on indoor models, integrated temperature and pump controls with advanced diagnostics; the T-D2 does not print integrated recirculation.
A consultation includes a heat-loss review so the size is right the first time.
On-site service in Greater Vancouver, BC. ROMA lists “Open 7 days” on its site; call to confirm same-day availability.
Sources and verification
Facts checked September 9, 2026. Last updated September 9, 2026. Technical reviewer: not yet assigned.