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Comparison

Rinnai RU199iN vs RX199iN

Verdict in brief

The RX199iN is Rinnai's current flagship and the successor platform to the RU199iN: the same 199,000 BTU/h input class, a taller cabinet, built-in Wi-Fi, ENERGY STAR marked on rinnai.ca, and UEF 0.98 against the RU's 0.95. Both deliver their real capacity as flow at the winter temperature rise, not at the unstated-rise maximum. Choose the RU only where a specific reason (price, existing spec) keeps the older platform in play; otherwise the RX is the current unit.

Side by side

Published manufacturer figures with units. Storage and flow figures are different measures and are shown on their own rows; blanks mean not applicable or not published.

Comparison of Rinnai RU199iN and Rinnai RX199iN
SpecificationRinnai RU199iNGas tanklessRinnai RX199iNGas tankless
Minimum gas input15,000 BTU/h15,000 BTU/h
Maximum gas input199,000 BTU/h199,000 BTU/h
Maximum flow with parameter adjustment11 GPM (42 L/min) at unspecified rise rise11.1 GPM (42 L/min) at unspecified rise rise
Minimum activation flow0.4 GPM (1.5 L/min)0.4 GPM (1.5 L/min)
Uniform Energy Factor (UEF)0.950.98
Height26.4 in (670 mm) cabinet; 31.3 in (795 mm) with fittings per rinnai.ca30.11 in (762 mm)
Width18.5 in (470 mm)18.5 in (470 mm)
Depth11.4 in (290 mm)11.4 in (291 mm)
Weight64 lb (29 kg)55 lb (24.5 kg)
Condensate drain1/2 in NPT (13 mm)1/2 in NPT (13 mm)

“—” means not applicable to that system type or not published by the manufacturer. Flow figures are only comparable at the same temperature rise; UEF values are only comparable within the same draw pattern.

What actually separates them

The two units share the 15,000–199,000 BTU/h input class and the same installation pattern: 2 in PVC-family venting, a 3/4 in gas connection, a condensate drain and 120 V power. The RX differs physically with a 30.11 in (762 mm) cabinet against the RU's 26.4 in (670 mm), and electronically with Wi-Fi control and ENERGY STAR marking on rinnai.ca.

Rinnai rates the RU199i at UEF 0.95 and the RX199i at 0.98; both are Uniform Energy Factors for the tankless class and neither should be compared with a legacy EF or with a storage tank's UEF at a different draw pattern.

Both publish a maximum flow without a stated rise: 11 GPM (42 L/min) on the RU by parameter adjustment and 11.1 GPM (42 L/min) on the RX. In Metro Vancouver's winter, when the rise to 49 °C approaches 40 °C, the deliverable flow from the manufacturer's flow-at-rise tables is the sizing figure, and it is far below either maximum for two simultaneous showers.

Rinnai Canada still lists the RU199iN as of the verification date, but its tankless listing leads with the RX and RXP series, which is the signal that the RU is the outgoing platform. Availability is re-checked before ordering.

Rinnai · Gas tankless

Rinnai RU199iN

CurrentSold in Canada
Max input
199,000 BTU/h
Flow at unspecified rise rise
11 GPM (42 L/min)
Uniform Energy Factor (UEF)
0.95

The Rinnai RU199iN is an indoor condensing natural gas tankless water heater with a 15,000–199,000 BTU/h input, UEF 0.95, 2" PVC venting and up to 11 GPM (42 L/min) of flow at an unstated temperature rise. It is listed on rinnai.ca and is the largest residential RU model, with a propane version, the RU199iP.

Natural gasPropaneCondensing, PVC/CPVC/PP
Specifications, manuals and service

Rinnai · Gas tankless

Rinnai RX199iN

CurrentSold in Canada
Max input
199,000 BTU/h
Flow at unspecified rise rise
11.1 GPM (42 L/min)
Uniform Energy Factor (UEF)
0.98

The Rinnai RX199iN is Rinnai's current flagship indoor condensing natural gas tankless water heater in Canada: 15,000–199,000 BTU/h, UEF 0.98, up to 11.1 GPM (42 L/min) maximum flow at an unstated rise, Wi-Fi control and ENERGY STAR marked on rinnai.ca. It is the RX successor to the RU199iN.

Natural gasPropaneCondensing, PVC/CPVC/PP
Specifications, manuals and service

Frequently asked questions

Should I buy the RU199iN or the RX199iN?

Where both are available and the price difference is acceptable, the RX199iN is the current unit with the higher UEF and Wi-Fi. The RU only makes sense when a specific reason keeps the older platform in play.

Are their flow ratings comparable?

Both are maximum-flow figures without a stated rise, so neither is a winter capacity number. Size both from flow at the winter rise.

Not sure which one fits your home?

A consultation includes a hot-water demand review so capacity is right for your winter, not the brochure's.

On-site service in Metro Vancouver, BC. Call to check availability.

Call 604-359-1081Request a consultation

Related

Sources and verification

Facts checked September 7, 2026. Last updated September 7, 2026. Technical reviewer: not yet assigned.

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