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Comparison

Rinnai RX199iN vs RX180iN

Verdict in brief

Both are indoor condensing units in Rinnai's current RX flagship series, sharing UEF 0.98, the same 30.11 in cabinet, the same 3/4 in gas and water connections, the same 1/2 in condensate drain and 120 V supply, and the same ENERGY STAR marking on rinnai.ca. The only real difference is the burner: the RX199iN is rated 15,000–199,000 BTU/h with an 11.1 GPM (42 L/min) maximum flow, and the RX180iN is 15,000–180,000 BTU/h with 10.0 GPM (38 L/min). Neither maximum carries a stated temperature rise, so winter sizing uses Rinnai's flow-at-rise tables, not these headline numbers.

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 RX199iN and Rinnai RX180iN
SpecificationRinnai RX199iNGas tanklessRinnai RX180iNGas tankless
Minimum gas input15,000 BTU/h15,000 BTU/h
Maximum gas input199,000 BTU/h180,000 BTU/h
Maximum domestic hot-water flow11.1 GPM (42 L/min) at unspecified rise rise10.0 GPM (38 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)0.980.98
Vent materialPVC, CPVC or polypropylene (condensing)PVC, CPVC or polypropylene (condensing)
Gas connection3/4 in3/4 in
Water connections3/4 in cold inlet and hot outlet3/4 in cold inlet and hot outlet
Condensate drain1/2 in NPT (13 mm)1/2 in NPT (13 mm)
Electrical supply120 V, 60 Hz120 V, 60 Hz
Height30.11 in (762 mm)30.11 in (762 mm)
Width18.5 in (470 mm)18.5 in (470 mm)
Depth11.4 in (291 mm)11.4 in (291 mm)
Weight55 lb (24.5 kg)55 lb (24.5 kg)
CertificationSCAQMD ultra-low-NOx approvedSCAQMD ultra-low-NOx approved

“—” 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 RX platform is where the two are identical. Both are rated UEF 0.98 on natural gas or propane, both take PVC, CPVC or polypropylene condensing venting, both connect to 3/4 in gas and 3/4 in water, both drain condensate through a 1/2 in NPT connection, and both run on 120 V with Wi-Fi capability. Rinnai marks both ENERGY STAR and certifies both SCAQMD ultra-low-NOx on its Canadian product pages.

The difference is the input cap and the flow that follows from it: 199,000 against 180,000 BTU/h, and an 11.1 GPM (42 L/min) against 10.0 GPM (38 L/min) maximum flow. Rinnai publishes both maximums without a temperature rise, so they are marketing figures rather than winter performance. Metro Vancouver's rise to a 49 °C shower approaches 40 °C (72 °F), and the deliverable flow at that rise is read from the flow tables in manual 100000839, not from the maximum.

Physically the two share the cabinet exactly (30.11 in high, 18.5 in wide, 11.4 in deep, 55 lb / 24.5 kg) and the same 0.4 GPM (1.5 L/min) minimum activation flow. Neither carries a recirculation pump: both support recirculation with an external pump, and the RXP199iN is the RX-platform version with the pump built in.

The practical question is demand, not preference. A household whose peak is two sequential fixtures is usually served by the RX180iN; a home that runs two fixtures at once in January, or has a higher winter rise, is assessed against the RX199iN's larger input. Both are sized from measured simultaneous flow, and the gas supply and vent route are confirmed before either is specified. Whether CANRO stocks a given model for a job is confirmed at consultation.

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

Rinnai · Gas tankless

Rinnai RX180iN

CurrentSold in Canada
Max input
180,000 BTU/h
Flow at unspecified rise rise
10.0 GPM (38 L/min)
Uniform Energy Factor (UEF)
0.98

The Rinnai RX180iN is an indoor condensing natural gas tankless water heater in Rinnai's current RX flagship series: 15,000–180,000 BTU/h, UEF 0.98, up to 10.0 GPM (38 L/min) maximum flow at an unstated rise, Wi-Fi control and ENERGY STAR marked on rinnai.ca.

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

Frequently asked questions

Is the RX199iN worth it over the RX180iN?

Only if the peak demand needs the extra 19,000 BTU/h. Both share UEF 0.98, the same cabinet, venting, connections and ENERGY STAR marking; the RX180iN covers sequential use, while the larger unit adds winter capacity for simultaneous fixtures.

Can I compare their GPM directly?

As published, yes: 11.1 GPM against 10.0 GPM. But neither maximum states a temperature rise, so the honest comparison is flow at the same rise from Rinnai's flow tables.

Do the RX199iN and RX180iN use the same venting and power?

Yes. Both are condensing units taking PVC, CPVC or polypropylene venting to an exterior termination, with a 1/2 in condensate drain, 3/4 in gas and water connections and 120 V power.

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 19, 2026. Last updated September 19, 2026. Technical reviewer: not yet assigned.

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