Bosch Therm 830 ES
Amazon customer rating as of
Tankless Geek editorial score: 4.2/5
The Bosch Therm 830 ES is a non-condensing whole-house tankless rated at 175,000 BTU/h and up to 8.3 GPM (at a 35 °F rise), here in the propane version. It leans on Bosch's sealed-combustion, dual-fan design — which lets it vent through a side wall or roof with 3- or 4-inch stainless pipe and install in more locations than an atmospheric unit — plus built-in freeze protection, an externally accessible water filter, and a low 0.5 GPM minimum activation flow that helps with small draws.
Being non-condensing, it trades some efficiency (around 82% thermal) for a lower purchase price and simpler-than-condensing plumbing (no condensate drain), but it does require stainless venting rather than PVC. Bosch rates it for recirculation, solar-thermal, and space-heating tie-ins, and backs it with a long heat-exchanger warranty. One practical caveat: the Therm ES generation is older and being phased out, so confirm current availability and parts support before committing.
Key Features
Best Use Cases
Our Verdict
A high-flow, flexible-venting non-condensing propane unit for whole-house use where you'd rather save on the heater and skip a condensate drain than chase maximum efficiency. Its sealed combustion and 0.5 GPM minimum flow are real strengths. Verify parts/availability given it's a legacy model, and budget for stainless venting.
Technical Specifications
| Input | 175,000 BTU/h (propane) |
|---|---|
| Max flow | Up to 8.3 GPM (at 35 °F rise) |
| Min flow | 0.5 GPM activation |
| Efficiency | ≈82% thermal, non-condensing · ENERGY STAR |
| Venting | 3–4 in stainless; side-wall or roof |
| Extras | Sealed combustion, freeze protection, external filter |
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 (175,000 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) — capped at max | 8.3 GPM |
| 45 °F | Mild climate (65 °F in → 110 °F) | 6.4 GPM |
| 60 °F | Cool climate (50 °F in → 110 °F) | 4.8 GPM |
| 70 °F | Cold climate (40 °F in → 110 °F) | 4.1 GPM |
Usable flow at a 110 °F target: BTU × thermal-eff ÷ (ΔF × 500), capped at the 8.3 GPM maximum. Non-condensing efficiency (~82%) is applied.
Pros
Cons
Buy it if…
- Whole-house propane homes wanting 8+ GPM without condensing complexity
- Installs that benefit from flexible side-wall or roof venting
- Homes with small/low-flow draws (0.5 GPM activation)
- Recirculation, solar-thermal, or space-heating tie-ins
Skip it if…
- Buyers prioritizing maximum efficiency (choose condensing)
- Installs where PVC venting is strongly preferred over stainless
- Anyone needing assured long-term parts from a current model line
Installation Requirements
Professional vs DIY
Propane and Category III venting make this a licensed-pro install; incorrect gas or vent work is both a safety and a warranty risk.
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 (3.9/5 Amazon customer rating, 43 ratings, as of 2026-08-23). These are owner opinions, not our own bench testing.
Owners cite ample simultaneous hot water for a full house from the 175,000 BTU burner in warm and mild conditions.
Sealed combustion and dual-fan venting let it go in more locations, with side-wall or roof venting options.
The 0.5 GPM minimum activation flow is praised for triggering on low-flow fixtures where some units won't fire.
At ~82% thermal efficiency it uses more gas per gallon than a condensing unit and needs stainless venting — the cost of the lower price.
Bosch Therm 830 ES FAQ
Is the Therm 830 ES condensing?+
No — it's non-condensing at roughly 82% thermal efficiency. That means no condensate drain, but it needs 3–4 inch stainless venting rather than PVC and uses more gas per gallon than a condensing unit.
How low a flow will trigger it?+
It activates at about 0.5 GPM, which helps with trickle draws at a single faucet — better than many units that need a higher minimum flow.
Can it be used for recirculation or space heating?+
Yes — Bosch rates the Therm ES for recirculation, solar-thermal, and space-heating applications in addition to standard domestic hot water.
Is this a current model?+
The Therm ES generation is older and being phased out. It's still sold through supply channels, but confirm availability and parts support before buying.
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.
- Bosch Therm 830 ES engineering submittal (PDF) (accessed 2026-08-23)
- Bosch Therm 830 ES LP — SupplyHouse (accessed 2026-08-23)
- Bosch 830 ES LP — Amazon listing (accessed 2026-08-23)
Price range from leading retailers
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