Rheem RTG-70XLN-3
Amazon customer rating as of
Tankless Geek editorial score: 4.3/5
The Rheem RTG-70XLN-3 is the outdoor version of the mid-efficiency RTG line — the same 160,000 BTU/h, 7.0 GPM, 0.82 UEF non-condensing natural-gas engine as the indoor DVLN, but built for exterior wall mounting. The 'X' means external: it vents directly to open air, so there's no indoor flue to route, no venting materials to buy, and no wall penetration for exhaust. For warm-climate homes, that makes it one of the simplest gas tankless installs available.
It carries Hot Start Programming to minimize cold-water bursts and delivers a genuine 7.0 GPM for a small-to-medium home. Living outdoors, it relies on built-in freeze protection — which only works while the unit has power. That's the central caveat: an outdoor gas tankless in a cold snap without electricity is at real risk, and freeze damage is typically excluded from warranty coverage.
Key Features
Best Use Cases
Our Verdict
The RTG-70XLN-3 is the easy-button version of Rheem's mid-efficiency line, and it shows in owner satisfaction — it rates noticeably higher than its indoor sibling largely because outdoor mounting removes the venting and clearance headaches that frustrate DVLN owners. You get the same 7.0 GPM and Hot Start for the same money, minus the flue. The honest catch is climate: it's genuinely at home in warm and mild regions, and in cold climates you must keep it powered year-round and insulate exposed lines, because a freeze failure is on you, not the warranty. Our take: an excellent-value outdoor gas tankless for warm-to-mild climates and simple installs — just respect the freeze-protection rules if your winters get hard.
Technical Specifications
| Max gas input | 160,000 BTU/h |
|---|---|
| Max flow rate | 7.0 GPM |
| Efficiency (UEF) | 0.82 · non-condensing |
| Installation | Outdoor (external) — no indoor venting |
| Emissions | Low-NOx |
| Hot Start | Yes — reduces cold-water bursts on back-to-back use |
| Freeze protection | Built-in (requires continuous power) |
| Dimensions (W×H×D) | 13.9 × 25.6 × 10.2 in |
| Weight | ≈46.5 lb |
| 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 (160,000 BTU × 0.82 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) | 7 GPM |
| 45 °F | Mild climate (65 °F in → 110 °F) | 5.8 GPM |
| 60 °F | Cool climate (50 °F in → 110 °F) | 4.4 GPM |
| 70 °F | Cold climate (40 °F in → 110 °F) | 3.7 GPM |
Usable flow calculated from rated output (160,000 BTU × 0.82 UEF), capped at the unit's 7.0 GPM maximum.
Pros
Cons
Buy it if…
- Warm-to-mild climates where an outdoor unit stays safe year-round
- Installs that benefit from skipping indoor venting entirely
- Small-to-medium homes wanting 7.0 GPM at a value price
- Owners who want the simplest possible gas tankless install
Skip it if…
- Cold climates prone to power outages — freeze risk is real and uncovered
- Homes that need an indoor unit — choose the RTG-70DVLN-3
- Efficiency-focused buyers — a condensing RTGH uses less gas
- Heavy simultaneous demand in cold-groundwater regions
Installation Requirements
Professional vs DIY
Outdoor install skips the venting, but the gas connection still belongs to a licensed pro; keep it powered so freeze protection works.
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, 311 ratings, as of 2026-09-13). These are owner opinions, not our own bench testing.
Outdoor mounting removes indoor venting and clearance work entirely — owners rate it higher than the indoor DVLN largely for the simpler install.
Reliable 7.0 GPM with Hot Start Programming for a small-to-medium warm-climate home, at a value price.
Freeze risk is the standout caution — one owner reported a unit rupturing in cold weather with the freeze damage denied under warranty; continuous power and pipe insulation are essential.
Code 11 (ignition/flame failure) is the most common Rheem gas fault and appears across the RTG line.
Non-condensing efficiency (0.82 UEF) and reduced flow in cold-groundwater regions.
Rheem RTG-70XLN-3 FAQ
Will it survive freezing weather?+
It has built-in freeze protection, but that only works while the unit has power. Outdoors, a winter power outage is the real danger — freeze damage is typically excluded from warranty. Keep it energized year-round, insulate exposed pipes, and think hard before choosing an outdoor unit in a hard-freeze climate.
How is it different from the RTG-70DVLN-3?+
Same 160,000 BTU/h, 7.0 GPM, 0.82 UEF engine and Hot Start. The XLN mounts outdoors and vents to open air, so there's no indoor flue — a simpler, cheaper install. The DVLN is the indoor direct-vent version for homes that can't mount outside.
Why does it rate higher than the indoor version?+
Mostly the install. Outdoor mounting eliminates the venting and clearance issues that frustrate indoor DVLN owners, so satisfaction runs higher even though the heater itself is essentially the same.
How much hot water does it deliver?+
Up to 7.0 GPM in warm climates — two showers plus a sink. In cooler regions usable flow drops toward 4–4.5 GPM. It's sized for a small-to-medium home.
What's the warranty?+
12 years on the heat exchanger — 15 with registration within 90 days — plus 5 years on parts and 1 year of labor. Note that freeze damage is generally not covered.
Product sources
Specifications verified 2026-09-13. Manufacturer documents are treated as the primary source for model specifications. Retailer pages are used only for customer ratings and owner-feedback themes.
- Rheem RTG-70XLN-3 official product page (accessed 2026-09-13)
- Amazon — Rheem RTG-70XLN-3 listing (rating & buyer reviews) (accessed 2026-09-13)
- Amazon — RTG-70XLN customer reviews (freeze/cold-weather feedback) (accessed 2026-09-13)
Price range from leading retailers
* As an Amazon Associate, we earn from qualifying purchases
