Bosch Therm 940 ES
The Bosch Therm 940 ES is the top of Bosch's non-condensing Therm line: 199,000 BTU/h and up to 9.4 GPM of natural-gas hot water — enough for three-plus bathrooms even in cool climates. Like its smaller sibling it uses sealed combustion and dual-fan technology for flexible 3- or 4-inch stainless venting (side-wall or roof), with electronic ignition, built-in freeze protection, and an externally accessible water filter. It measures 30½ × 17¾ × 11¼ inches and weighs about 67 pounds.
At roughly 83% thermal efficiency it's non-condensing — so no condensate drain, but more gas per gallon than a condensing unit and stainless (not PVC) venting. What you get for that is one of the highest flow rates here without the price and plumbing of a condensing heater, backed by a long heat-exchanger warranty. As with the 830 ES, note the Therm ES generation is legacy and being phased out; check availability and parts before buying.
Key Features
Best Use Cases
Our Verdict
The high-capacity pick in Bosch's non-condensing line — 9.4 GPM for a large home without a condensate drain. A strong value where flow matters more than squeezing out maximum efficiency. Plan for stainless venting, and confirm parts/availability since it's an older model line.
What owners report
Themes summarized from verified-purchase reviews across major retailers (4★ average, 67 ratings). These are aggregated owner opinions — not our own bench testing.
Owners praise the 199,000 BTU burner for running several fixtures at once without temperature drop in warm and mild climates.
Sealed combustion and dual-fan design allow side-wall or roof venting and installation in tighter spaces.
At ~83% thermal efficiency it uses more gas per gallon than a condensing unit and requires stainless venting — the cost of the higher flow at a lower price.
The Therm ES line is being phased out; owners and installers should confirm parts and service availability.
Bosch Therm 940 ES FAQ
How many bathrooms can the 940 ES run?+
Up to about 9.4 GPM in warm/mild climates — comfortably three or more bathrooms at once. In cold weather deliverable flow drops toward 4.7–5.4 GPM.
Is it condensing?+
No. It's non-condensing at roughly 83% thermal efficiency — no condensate drain, but it needs 3–4 inch stainless venting and uses more gas per gallon than a condensing model.
How big is it and where can it go?+
About 30.5 × 17.75 × 11.25 inches and 67 pounds, with sealed combustion allowing flexible side-wall or roof venting for varied install locations.
Is it still available?+
It's a legacy Therm ES model still sold through supply channels but being phased out — verify stock and parts support before purchasing.
Price range from leading retailers
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