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Written from the listing's specs, not from our own use · How we rate
The Bosch Tronic 4000 (10.5 kW) keeps it simple: a point-of-use heater with a compact 10.5 kW element. It is a good match for a powder room, a garage sink or a tiny house, at 6.5/10 on its documented specs.
| Brand | Bosch |
|---|---|
| Category | Electric tankless water heaters |
| Fuel | Electric |
| Stated heating power | 10.5 kW |
| ASIN | B0BWKDBT8F |
Full listing title: Bosch Thermotechnology Tronic 4000 Electric Tankless Water Heater, 10.5 kW, 13 x 8.5 x 4.5", White
| Fuel | ElectricFull listing title |
|---|---|
| Stated heating power | 10.5 kWFull listing title |
Rated from the listing's specs, no buyer reviews yet
What it's made for: a powder room, a garage sink or a tiny house.
Two electric tankless heaters of about the same power, closest to it on our rating, each with a dated price.
The heating power the listing states. On our calculator's maths it gives about 1.7 GPM of 105 °F water when the tap water comes in at 62 °F, and less in winter. Enough for a kitchen or a bathroom sink.
One sink: about 1.7 GPM of 105 °F water with 62 °F tap water, on our calculator's maths. That covers a kitchen or a bathroom sink.
A shower: no. A shower takes about 2 GPM, and 10.5 kW gives about 1.7 on a warm day.
At the price on Sep 30, 2026, each kW of stated heating power works out at about $21.87 (price ÷ stated kW, our arithmetic). That puts it in the cheaper third of the 17 point-of-use heaters we have a price and a stated power for.
Unless it plugs into an existing outlet, an electrician runs the circuit; the plumbing under the sink is the smaller job.
The button opens the exact listing (ASIN B0BWKDBT8F), where today's price, stock and seller apply.
Want the shower covered too? The Rheem 18 kW Electric, 240V (9.3/10) is an 18 kW whole-house unit.
Want it to draw only what it needs? The Stiebel Eltron DHX 12-2 Trend, 12 kW (6.8/10) is self-modulating, per its listing.
Our take
The Bosch Tronic 4000 (10.5 kW) is about a compact 10.5 kW element, and it doesn't pretend to be more. No buyer reviews yet, so the Bosch Tronic 4000 (10.5 kW) has to win you over on paper. Honestly, the catch: no word on the breakers it needs or the flow. We'd pick it if the kitchen or the powder-room sink takes forever to run hot; otherwise, put it next to the HNK 3,500 W Electric (110V) first.
the unit on the wall next to the old tank's spot, water in and out. Under a sink or on the wall beside it, close to the tap it feeds.
Hot in a few seconds once the water in the pipes has passed. Set it, then leave it.
With 42 °F water coming in, 10.5 kW gives about 1.1 GPM at 105 °F on our calculator's maths. Low-flow shower heads stretch that further.
Clean the inlet screen and flush out scale on hard water. Our flushing and descaling guide has the routine.
Before the Bosch Tronic 4000 (10.5 kW) goes in your cart, check the tap it will feed: 10.5 kW suits one sink or a low-flow shower.
10.5 kW warms one sink or one low-flow shower, not two. Decide the fixture first, then check the flow it needs. Our point-of-use guide explains the trade-off.
At 240 V it needs a dedicated circuit; an electrician confirms the breaker and the wire.
Small units need a minimum flow to switch on. Ask the seller for that figure if you have low-flow aerators.
Electric units scale too, mostly at the inlet screen and the element. Our flushing and descaling guide covers the routine.
How the Bosch Tronic 4000 (10.5 kW) stacks up against the closest alternative, the HNK 3,500 W Electric (110V).
| Criterion | Bosch Tronic 4000, 10.5 kW | HNK 3,500 W Electric, 110V |
|---|---|---|
| Our rating | 6.5/10 | 6.7/10 |
| Heating power | 10.5 kW | Not stated |
| Voltage | Not stated | 110 V |
Pick the HNK 3,500 W Electric (110V) if you want our higher-rated option (6.7/10); stay with the Bosch Tronic 4000 (10.5 kW) for more power (10.5 kW).
We rate it 6.5/10 (good). The rating comes from its documented listing alone, as no customer-review record is captured yet.
The listing states a heating power of 10.5 kW. The headline flow is a mild-weather number: with cold winter water coming in, the same unit gives you less. Read the maker's flow chart at your winter rise, or let our flow-rate calculator do the sums.
The listing doesn't state the voltage, so check the maker's documents. A licensed electrician checks the panel, the breakers and the wiring before it goes on the wall.
Its listing states 10.5 kW for one tap. These are the seller's figures, not our measurements: how steady the temperature is in your shower and how it copes with your winter water can't be read from a listing.
Which tap: 10.5 kW warms one sink or one low-flow shower, not two. Decide the fixture first, then check the flow it needs. Our point-of-use guide explains the trade-off. Power: at 240 V it needs a dedicated circuit; an electrician confirms the breaker and the wire. Activation flow: small units need a minimum flow to switch on. Ask the seller for that figure if you have low-flow aerators. Scale: electric units scale too, mostly at the inlet screen and the element. Our flushing and descaling guide covers the routine.
We link to the exact listing on Amazon, where today's price, stock and seller apply. It is an affiliate link, and it has no effect on the rating.
No, we haven't used it ourselves. Everything on this page comes from its listing, read line by line and weighed with our published formula.