Rheem IKONIC S84iN
Amazon customer rating as of
Tankless Geek editorial score: 4.5/5
The Rheem IKONIC S84iN (model RECTGH-S84iN) is the natural-gas, non-recirculating unit in Rheem's flagship IKONIC line — a super-high-efficiency condensing tankless rated at 157,000 BTU/h and 8.4 GPM. It's the most feature-dense residential tankless Rheem makes: dual condensing heat exchangers for efficiency, built-in EcoNet Wi-Fi, and — most distinctively — the LeakGuard leak-detection system with a factory-installed automatic shut-off valve.
What sets IKONIC apart isn't raw output — 8.4 GPM matches the RTGH-84DVLN — but the intelligence wrapped around it. LeakGuard detects a leak at the unit and closes the water supply, limiting any leak to about 20 ounces, with alerts pushed to the EcoNet app. It's a genuinely compact, wall-mount chassis with class-leading installation clearances. Note the naming: the plain S84iN does not include a recirculation pump — that's the SR84iN variant.
Key Features
Best Use Cases
Our Verdict
The IKONIC S84iN is for the owner who wants the smartest, best-protected tankless Rheem sells and is willing to pay for it. Its condensing efficiency and 8.4 GPM are strong but not unique in Rheem's range; what you're really buying is LeakGuard's automatic water shut-off and the EcoNet ecosystem — real value if water-damage protection and app control matter to you. The honest counterpoints are price (it's near the top of the residential market) and the added complexity that comes with any smart, connected appliance — Wi-Fi setup and firmware are more to manage than a dumb unit. Our take: worth it for tech-forward owners and anyone who's had a water-leak scare; if you just want efficient hot water, the RTGH-84DVLN delivers the same flow and UEF for meaningfully less, and if you want recirculation, step up to the SR84iN.
Technical Specifications
| Max gas input | 157,000 BTU/h |
|---|---|
| Max flow rate | 8.4 GPM |
| Efficiency (UEF) | 0.94 · condensing (ENERGY STAR) |
| Leak protection | LeakGuard — auto shut-off, limits leaks to ~20 oz |
| Connectivity | Built-in EcoNet Wi-Fi |
| Recirculation | Not included (see SR84iN for built-in pump) |
| Heat exchanger | Dual (condensing) |
| Dimensions (W×H×D) | 17.3 × 28.6 × 13.7 in |
| Electrical | 120 V |
| Emissions | Low-NOx, ENERGY STAR certified |
| Warranty | 12 yr heat exchanger (15 yr w/ registration) · 5 yr parts · 1 yr labor |
Specifications verified against the linked source documents. See Sources below.
How much hot water you'll actually get
Usable flow drops as incoming water gets colder. Figures are calculated from rated output (157,000 BTU × 0.94 UEF) and labeled as such — not bench-tested by us.
| Temperature rise | Typical scenario | Usable flow |
|---|---|---|
| 35 °F | Warm climate (75 °F in → 110 °F) | 8.4 GPM |
| 45 °F | Mild climate (65 °F in → 110 °F) | 6.6 GPM |
| 60 °F | Cool climate (50 °F in → 110 °F) | 4.9 GPM |
| 70 °F | Cold climate (40 °F in → 110 °F) | 4.2 GPM |
Usable flow calculated from rated output (157,000 BTU × 0.94 UEF), capped at the unit's 8.4 GPM maximum.
Pros
Cons
Buy it if…
- Owners who want built-in leak protection with automatic water shut-off
- Smart-home users who'll actually use the EcoNet app and alerts
- 2–3 bathroom homes wanting condensing efficiency plus 8.4 GPM
- Tight installs that benefit from the compact, low-clearance chassis
Skip it if…
- Budget buyers — the RTGH-84DVLN offers the same flow/UEF for less
- Anyone who wants recirculation built in — choose the SR84iN instead
- Owners who prefer a simple unit with no app or connectivity to manage
- Installs with no condensate drain — condensing units require one
Installation Requirements
Professional vs DIY
A condensing smart unit — gas sizing, sealed venting, and condensate make this a licensed-pro job to keep the 12–15-year warranty.
Gas and electrical work should be done by a licensed professional, and most installs require a permit and must meet local building codes — DIY work can void the manufacturer warranty. Always confirm the unit's own manual for exact clearances, venting, and sizing.
What owners report
Themes summarized from retailer customer feedback (4.4/5 Amazon customer rating, 28 ratings, as of 2026-08-23). These are owner opinions, not our own bench testing.
Quiet, reliable on-demand hot water paired with genuinely useful EcoNet app control — temperature, schedules, and usage from a phone.
LeakGuard's automatic shut-off valve is the standout feature; owners value that a leak at the unit is capped at roughly 20 ounces with an app alert.
Compact wall-mount design with class-leading installation clearances fits spaces that larger units can't.
It's a premium-priced unit — among the most expensive residential tankless options, which not every buyer needs.
As a newer smart appliance, Wi-Fi/app setup and firmware add complexity compared with a basic tankless.
Rheem IKONIC S84iN FAQ
What is LeakGuard and is it worth it?+
LeakGuard is Rheem's built-in leak detection paired with a factory-installed automatic shut-off valve. If it senses a leak at the unit it closes the water supply — limiting the spill to about 20 ounces — and alerts you in the EcoNet app. If a past water leak has cost you, it's the main reason to choose IKONIC over a standard RTGH.
Does the S84iN have a recirculation pump?+
No. The plain S84iN is the non-recirculating model. If you want built-in recirculation for near-instant hot water at the tap, choose the SR84iN, which adds a factory recirculation pump and EcoNet-based pump scheduling.
How is it different from the RTGH-84DVLN?+
Same 8.4 GPM and condensing efficiency. The IKONIC adds built-in Wi-Fi, LeakGuard leak protection with auto shut-off, and a more compact smart chassis. If you don't need those, the RTGH-84DVLN delivers the same hot-water performance for less money.
Do I need special venting or a drain?+
Yes — like any condensing unit it produces condensate and needs a nearby drain, and it uses PVC/CPVC venting. Its compact clearances make tight installs easier than most condensing units, but the drain requirement doesn't change.
What's the warranty?+
12 years on the heat exchanger — extendable to 15 years if you register within 90 days of installation — plus 5 years on parts and 1 year of labor.
Product sources
Specifications verified 2026-08-23. Manufacturer documents are treated as the primary source for model specifications. Retailer pages are used only for customer ratings and owner-feedback themes.
- Rheem — IKONIC tankless overview (accessed 2026-08-23)
- Rheem — LeakGuard / smart leak-prevention features (accessed 2026-08-23)
- Amazon — Rheem IKONIC RECTGH-S84iN listing (rating & buyer reviews) (accessed 2026-08-23)
Price range from leading retailers
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