Quick Answer: Bosch’s entire tankless lineup is now discontinued — not just the gas line. The Greentherm/Therm 9000-series units (T9800/T9900) have long appeared under “Discontinued Products” on Bosch’s own Home Comfort site, and as of our September 2026 recheck, Bosch’s site now lists the entire electric Tronic 3000 tankless line there too, including the US9-2R and US12 models this guide previously called Bosch’s “genuinely current” product. If you want a gas unit anyway, the Greentherm T9900i SE199 is the best of the closeout stock — 199,000 BTU, 11.2 GPM at a 35°F rise, 0.96 UEF, built-in recirculation pump, Wi-Fi app, 15-year heat-exchanger warranty, $2,610.40 at Home Depot (price unchanged since August). The electric Tronic 3000 US9-2R (9 kW, 2.5 GPM) is still buyable new at Home Depot for roughly $270-$300, but it’s closeout stock now too, not an ongoing product.
Most “best Bosch tankless water heater” roundups treat Bosch like any other in-production brand and rank the Greentherm 9000 series against Rinnai and Rheem on specs alone. That misses the fact that actually changes the buying decision: Bosch’s own website now files its entire tankless lineup — gas and electric — under discontinued products, the same status Takagi units carried before that brand wound down completely. This guide covers what’s still findable as genuine new-stock closeout inventory, and at what price it’s worth buying versus moving on to an in-production brand.
Our top picks at a glance
| Model | Best for | Type | BTU/kW | Peak flow | UEF/Efficiency | Price |
|---|---|---|---|---|---|---|
| Greentherm T9900i SE199 | Best overall (gas, closeout) | Condensing indoor, WiFi + pump | 199,000 BTU | 11.2 GPM @ 35°F rise | 0.96 UEF | $2,610.40 |
| Greentherm T9800 SE199 | Best value whole-home (gas) | Condensing indoor | 199,000 BTU | 11.2 GPM @ 35°F rise | 0.95 UEF | $1,926.60 |
| Greentherm T9800 SE160 | Best small-medium home (gas) | Condensing indoor | 160,000 BTU | 9.0 GPM @ 35°F rise | up to 0.95 UEF | $1,695.20 |
| Tronic 3000 US9-2R | Best point-of-use (electric, discontinued) | Point-of-use | 9 kW | 2.5 GPM | ~98% efficient | ~$270-$300 |
| Tronic 3000 US12 | Best high-output point-of-use | Point-of-use | 12 kW | 2.3 GPM | ~98% efficient | ~$230 |
Gas prices are Home Depot listings re-checked September 30, 2026 (unchanged since August); electric prices vary more by retailer and are approximate. All GPM figures for the Greentherm line are manufacturer-rated at a 35°F rise, not the harsher 60°F winter-groundwater benchmark our flow rate guide recommends sizing against.
The discontinuation now covers the whole lineup
Search “Bosch tankless water heater discontinued” and you’ll land on Bosch’s own Home Comfort site, which has long filed the Greentherm 9000 series — every T9800 and T9900 model — under Discontinued Water Heating Products, alongside a separate page for older Therm-series gas units. No press release accompanies it, and there’s no end-of-life banner on the retail listings themselves: Home Depot, Lowes, and wholesale suppliers still show current pricing and in-stock status for these SKUs as of September 2026.
That combination — manufacturer discontinuation notice, live retail inventory — is the identical pattern our Takagi brand guide documented for that line before it wound down completely. The practical read is the same too: you’re buying sell-through stock backed by a still-valid warranty, not a product Bosch will keep making. Bosch Thermotechnology is a division of the much larger Bosch Group, which lowers (though doesn’t eliminate) the risk of the warranty itself becoming worthless — the bigger long-run concern is parts and factory-trained service technicians thinning out over a 15-year heat-exchanger warranty term.
What changed since our last check: this guide previously pointed to Bosch’s Tronic 3000 electric point-of-use line as the “still current” answer, since it carried no discontinued notice at the time. That’s no longer true. Bosch’s own discontinued-electric-water-heaters page now explicitly lists the US12, US3-2R, US4-2R, US7-2R, and US9-2R — every current Tronic 3000 tankless model, including the two this guide recommends below — under discontinued products. Bosch’s tankless story in 2026 isn’t “gas discontinued, electric current” anymore; it’s discontinued across the board, and the honest framing for every pick below is closeout stock, not an ongoing product line.
By the numbers
- 0.96 UEF on the flagship Greentherm T9900i SE199, among the highest efficiency ratings in the condensing gas tankless category — every model in the 9000 series is ENERGY STAR certified. — Bosch Home Comfort specifications
- 15-year heat-exchanger warranty on the Greentherm gas line (5-year parts, 1-year labor upon registration), a term that runs independent of whether Bosch keeps manufacturing the model. — Bosch Home Comfort warranty documentation
- 12 kW is the ceiling on Bosch’s entire electric tankless lineup (the Tronic 3000 US12) — well under the 27–36 kW a whole-home electric unit needs, confirming Bosch’s electric line is point-of-use only. — Bosch Home Comfort product specifications
1. Bosch Greentherm T9900i SE199 — Best Overall (Closeout)
Bosch Greentherm T9900i SE199 (199,000 BTU Condensing, WiFi + Pump)
- Bosch's flagship: the same 199,000 BTU condensing core as the plain T9900 SE199, plus a factory-built recirculation pump and Wi-Fi app control (iOS/Android) for remote temperature and usage monitoring.
- Shatterproof VBL glass front — a cosmetic touch, but one that signals which unit in the lineup Bosch positioned as premium.
- 0.96 UEF and full ENERGY STAR certification put it ahead of the non-i model and competitive with Rinnai's and Navien's flagships on paper.
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If you’re buying into the Greentherm line at all, buy the top of it. A built-in recirculation pump means you skip the compatibility headache our recirculating pump guide covers in depth — most aftermarket tank-style pumps aren’t rated for tankless use, and this one is already matched to the unit. The Wi-Fi app is a genuine convenience, not a gimmick tacked on for the spec sheet.
2. Bosch Greentherm T9800 SE199 — Best Value Whole-Home
Bosch Greentherm T9800 SE199 (199,000 BTU Condensing)
- Same 199,000 BTU, 11.2 GPM core hardware as the flagship T9900i, minus the built-in pump and Wi-Fi — a roughly $684 saving for buyers who don't need either.
- Full-size whole-home capacity: comfortably runs two fixtures at once in most climates, per the manufacturer's 35°F-rise rating.
- Same 15-year heat-exchanger, 5-year parts warranty as the rest of the 9000 series.
This is the pick for a straightforward whole-home replacement where a recirculation loop and app control aren’t on the wish list. It undercuts the flagship by nearly $700 for the same peak flow and nearly identical UEF (0.95 vs. 0.96) — the Wi-Fi and pump are genuinely optional extras, not efficiency upgrades.
3. Bosch Greentherm T9800 SE160 — Best Small-Medium Home
Bosch Greentherm T9800 SE160 (160,000 BTU Condensing)
- Sized for a 1–2 bathroom home rather than the full 199,000 BTU flagship — right-sizing avoids paying for burner capacity you'll never use.
- Also sold in an outdoor-rated SEO160 version for installations without indoor venting clearance.
- Same condensing efficiency tier and warranty terms as the bigger 199-series units, just in a smaller BTU footprint.
Buying the 199,000 BTU flagship for a small home is the classic tankless oversizing mistake covered in our sizing guide — the SE160 is Bosch’s answer for a household that doesn’t need to run three fixtures simultaneously, at a real price saving over the 199-series units.
4. Bosch Tronic 3000 US9-2R — Best Point-of-Use (Now Also Discontinued)
Bosch Tronic 3000 US9-2R (9 kW Point-of-Use Electric)
- Now listed on Bosch's own discontinued-electric-water-heaters page alongside the rest of the Tronic 3000 lineup — this is sell-through stock, the same status as the gas line, not an ongoing Bosch product.
- Price has drifted up since our last check: Home Depot lists it around $299.70 (roughly $270 at 3+ units), up from the ~$263 we saw in August.
- ~98% efficient with minimal standby loss, since electric resistance heating has no combustion or venting losses to account for. Sized for a single fixture — a remote bathroom sink, a wet bar, a workshop — not a whole home's hot water.
This was the pick we recommended as Bosch’s “still current” product as of August; it no longer is. It’s still a reasonable point-of-use unit at the right price, but go in knowing it’s closeout inventory now, same caveats as the gas line below.
5. Bosch Tronic 3000 US12 — Best High-Output Point-of-Use (Discontinued)
Bosch Tronic 3000 US12 (12 kW Point-of-Use Electric)
- The top of Bosch's electric tankless range — 12 kW is the ceiling for the entire Tronic 3000 lineup, and this model is explicitly named on Bosch's discontinued-products page.
- Slightly lower peak GPM than the US9-2R despite the higher kW rating, since more of the higher wattage goes toward a bigger temperature rise rather than more flow.
- Best matched to a single low-flow shower or a fixture needing warmer output than the smaller US4/US7 models deliver — while remaining stock lasts.
This is as big as Bosch’s electric line ever got — which is the point of the gap flagged below. If 12 kW and 2.3 GPM don’t cover what you need, Bosch never had a bigger electric unit to sell you, and now it has none in active production at all.
The gap: Bosch has no whole-home electric tankless
Every other major electric tankless brand we cover — EcoSmart, Stiebel Eltron, A.O. Smith’s Signature line, and Rheem’s RTEX line in our electric roundup — builds units up to 27–36 kW that can run a full house on a large enough breaker panel. Bosch’s Tronic 3000 tops out at 12 kW, a single-fixture capacity by comparison. This isn’t a defect in Bosch’s electric line; it’s a deliberate scope limit, and it means Bosch simply isn’t a contender if what you’re shopping for is a whole-home electric replacement. For that use case, start with our best electric tankless water heater guide instead — Bosch won’t appear on that shortlist, and now you know why.
How to choose
- If you want a whole-home gas unit and don’t mind buying closeout stock: the Greentherm T9900i SE199 is the best of what’s left, backed by a 15-year heat-exchanger warranty that outlives the product line itself.
- If you want the same hardware for less and don’t need Wi-Fi or a built-in pump: the T9800 SE199 saves roughly $684 for nearly identical specs.
- If your home only needs 160,000 BTU of capacity: the T9800 SE160 avoids paying for flow you won’t use.
- If you want a compact point-of-use unit and don’t mind buying closeout stock here too: the Tronic 3000 US9-2R or US12 — sized for one fixture, not a house, and now discontinued same as the gas line.
- If you need whole-home electric tankless: skip Bosch entirely and compare EcoSmart, Stiebel Eltron, or Rheem’s RTEX line instead.
The bottom line
Bosch’s tankless story in 2026 no longer splits into “gas discontinued, electric current” — as of our September recheck, Bosch’s own site now lists its entire tankless lineup, gas and electric alike, under discontinued products. If you want the gas hardware, the T9900i SE199 ($2,610.40) is the best of the remaining stock, backed by a 15-year heat-exchanger warranty that holds regardless of production status. If you want a compact point-of-use unit, the Tronic 3000 US9-2R (~$270-$300, up from ~$263 in August) is still findable new — just go in knowing it’s closeout stock too, not an ongoing Bosch product. Buyers who want a brand actively building new tankless hardware should compare our best tankless water heater roundup and best gas guide instead — that’s the in-production competition Bosch’s entire line has now exited.