When a job calls for hot water at a single sink — a hand washing station, a break room kitchenette, a utility sink 100 feet from the water heater — the Stiebel Eltron Mini is the unit most contractors reach for. It is the most compact point-of-use electric tankless available, requires no venting, no pressure relief valve, and no drain connection, and installs directly under the sink in minutes. This guide covers every Mini model, confirmed specs from the official Stiebel Eltron brochure, and everything you need to know before you order.
PlumbersCrib.com is an authorized Stiebel Eltron dealer. Browse the full Stiebel Eltron lineup at PlumbersCrib.com or contact our team with sizing or spec questions.
What the Mini is — and what it is not
The Stiebel Eltron Mini is a point-of-use electric tankless water heater designed for a single low-flow application — typically a hand washing sink or utility sink. It heats water instantaneously as it flows through the unit using Stiebel Eltron's Direct Coil heating technology — nichrome heating elements contained in a glass-fiber reinforced heating chamber that silently vibrate on each start-up, providing self-cleaning action that confers superior limescale resistance and increased longevity. Standby heat losses are completely eliminated.
The Mini is not a whole-home water heater, not a shower unit, and not appropriate for applications with fluctuating flow rates or high simultaneous demand. It is purpose-built for consistent, low-flow, single-fixture applications. For applications with varying demand or higher flow requirements, the Stiebel Eltron DHC-E series with thermostatic control and flow-based power modulation is the more appropriate choice.
Because it is installed at the point of use — directly under or adjacent to the sink it serves — the Mini virtually eliminates the thermal heat loss associated with long pipe runs from a central water heater. On jobs where a sink is 50, 75, or 100+ feet from the main water heater, a point-of-use Mini is often a far more practical and energy-efficient solution than running a recirculation loop.
No venting. No pressure relief valve. No drain. Unlike gas tankless units, the Mini requires none of these — just an electrical connection and a water supply. This makes it one of the simplest tankless installations in the field. Connect power, connect water, done. The Mini has been sold in the United States for closing in on 20 years with a failure rate of less than one-half of one percent.
The Mini lineup — confirmed specs from the official Stiebel Eltron spec sheet
All specs below are pulled directly from the official Stiebel Eltron Mini Series brochure (printed 7.2025). All models share the same dimensions (6.5" H × 7.5" W × 3.25" D), weight (3.44 lbs), working pressure (150 PSI), and water connections (3/8" OD flexible braided stainless steel hose connectors).
| Specification | Mini 2-1 | Mini 3-1 | Mini 4-2 | Mini 6-2 |
|---|---|---|---|---|
| Item number | 231045 | 220816 | 222039 | 220817 |
| Voltage | 120V | 120V | 240V / 208V | 240V / 208V |
| Wattage | 1.8 kW | 3.0 kW | 3.5 kW / 2.6 kW | 5.7 kW / 4.3 kW |
| Amperage draw | 15A | 25A | 15A / 13A | 24A / 21A |
| Minimum recommended circuit breaker | 15A single pole | 25A single pole | 15A double pole | 25A single pole |
| Minimum recommended wire size | 14/2 AWG | 10/2 AWG | 14/2 AWG | 10/2 AWG |
| Minimum flow to activate | 0.21 GPM | 0.40 GPM | 0.40 GPM | 0.77 GPM |
| Included aerator | 0.35 GPM | 0.5 GPM | 0.66 GPM | 1.0 GPM |
| Uniform Energy Factor (UEF) | 0.99 | 0.94 | 0.95 / 0.99 | 0.94 / 0.98 |
| UEF recovery efficiency | 98% — all models | |||
| Dimensions | 6.5" H × 7.5" W × 3.25" D — all models | |||
| Weight | 3.44 lbs. — all models | |||
| Working pressure | 150 PSI (10 BAR) | |||
| Water connections | 3/8" OD flexible braided stainless steel hose connectors | |||
| Warranty | 10 years leakage / 3 years parts | |||
Sizing by climate zone
Which Mini model is right depends on your region's incoming water temperature. Colder inlet water requires more wattage to achieve the same output temperature at the same flow rate. Use the table below — all figures from the official brochure at a single lavatory sink target of 90°F:
| Model | Zone 1 (42°F inlet) | Zone 2 (52°F inlet) | Zone 3 (62°F inlet) | Zone 4 (72°F inlet) |
|---|---|---|---|---|
| Mini 2-1 | 0.3 GPM max | 0.3 GPM max | 0.3 GPM max | 0.3 GPM max |
| Mini 3-1 | 0.4 GPM max | 0.5 GPM max | 0.7 GPM max | 1.1 GPM max |
| Mini 4-2 | 0.5 GPM max | 0.6 GPM max | 0.85 GPM max | 1.3 GPM max |
| Mini 6-2 | 0.8 GPM max | 1.0 GPM max | 1.4 GPM max | 2.2 GPM max |
Cold climate note: In Zone 1 states (Minnesota, Wisconsin, Michigan, New England) where inlet water can be as cold as 42°F in winter, the Mini 2-1 is limited to 0.3 GPM regardless of the aerator installed. For cold climate commercial restroom applications, the Mini 6-2 gives the most headroom — 0.8 GPM max in Zone 1, enough to serve a single lavatory sink comfortably with the included 1.0 GPM aerator.
Which model for which application
Mini 2-1 — 1.8 kW, 120V. The simplest installation in the lineup. Internally restricted to 0.32 GPM — very low flow, suitable only for the most minimal hand washing applications in warm climates. The main advantage is the 120V single-pole 15-amp requirement, which can often be served by an existing circuit without new electrical work. Best for warm climate residential under-sink installations where a 120V circuit is already available.
Mini 3-1 — 3.0 kW, 120V. The most commonly specified 120V Mini for commercial restroom hand washing sinks. Delivers up to 0.5 GPM in Zone 2 and warmer climates with the included 0.5 GPM aerator. Requires a dedicated 25-amp single-pole breaker and 10/2 AWG wire — a new dedicated circuit run is typically required.
Mini 4-2 — 3.5 kW, 240V. Higher output than the 3-1 at lower amperage draw — only a 15-amp double-pole breaker required. Delivers up to 0.6 GPM in Zone 2 with the included 0.66 GPM aerator. The right choice when a 240V circuit is more accessible than a 120V circuit at the installation location.
Mini 6-2 — 5.7 kW, 240V. The highest-output Mini — best for cold climate installations, utility sinks with higher flow requirements, or any application where the smaller models cannot achieve adequate output temperature at the required flow rate. Requires a dedicated 25-amp, 240V circuit and 10/2 AWG wire.
Where the Mini works best
- Hand washing sinks in commercial restrooms — the most common application. Office buildings, restaurants, retail locations, and industrial facilities all use the Mini to provide warm water at restroom sinks without running a recirculation loop from a central water heater
- Break room and kitchenette sinks — compact enough to install under any standard sink cabinet, the Mini serves break room hot water needs without requiring a full water heater installation
- Remote utility sinks — when a utility or mop sink is far from the central water heater, a point-of-use Mini eliminates wait time and energy waste from long pipe runs
- ADA-compliant restroom additions — when adding a new ADA-compliant hand washing sink in a location without existing hot water, the Mini is the most practical solution
- Boats, RVs, and tight spaces — the 6.5" × 7.5" × 3.25" footprint and 3.44-pound body make it practical in space-constrained applications where no other tankless unit would fit
Installation notes
Mounting orientation. The Mini can be mounted above or below the fixture with fittings pointing up or down — four mounting orientations total. All units come with a pre-wired pigtail for the electrical connection.
Water connections. All Mini models use 3/8" OD flexible braided stainless steel hose connectors. Standard 3/8" supply lines connect directly — no special fittings required on most installations.
Aerator installation. Install the included pressure compensating flow reducer aerator on the faucet before use. Flow controls and aerators are required with the Mini — the unit is designed to operate at its rated flow rate. Higher flows will reduce output temperature and the unit may not maintain adequate warm water delivery.
No pressure relief valve, drain, or circulating pump required. Confirm local code requirements before installation — most jurisdictions do not require a PRV on point-of-use instantaneous heaters, but always verify.
Dry-fire protection. The flow switch control ensures the Mini will not dry-fire. All Mini models are also equipped with a safety high-limit with manual reset for additional protection. If the unit overheats it shuts off and requires a manual reset before it will operate again.
Water supply requirements. The Mini is suitable for supply with cold water only on mechanical models. Do not connect the Mini to a salt-regenerated water softener or a water supply of salt water.
Electrical requirements. Each Mini requires a dedicated circuit — do not share with other loads. Copper conductors must be used. Conductors should be sized to maintain a voltage drop of less than 3% under load. Confirm wire size and breaker requirements with a licensed electrician per local codes before installation.
Certifications
The Stiebel Eltron Mini is ETL listed, WQA certified against NSF/ANSI/CAN 372 for lead free compliance, and ISO 9001 certified. The Mini conforms to ANSI/UL Standard 499, CAN/CSA Standards E335-1 and E335-2-35. Made in Germany with final assembly in the USA.
Frequently asked questions
Which Mini model should I use for a commercial restroom hand washing sink?
For most commercial hand washing applications, the Mini 3-1 (120V, 3.0 kW) is the most commonly specified model in moderate to warm climates. In cold Zone 1 climates where incoming water may be 42°F or below in winter, the Mini 6-2 (240V, 5.7 kW) gives the most headroom. Contact our team if you are unsure which model is right for your application and climate.
Can the Mini be used for a shower?
No — the Mini is not designed for shower applications. It is a low-flow, single-fixture point-of-use unit for hand washing. For shower applications see the Stiebel Eltron Tempra series whole-home electric tankless lineup.
Does the Mini require a pressure relief valve?
No — the Mini does not require a pressure relief valve, drain connection, or circulating pump. Confirm local code requirements before installation.
What is the warranty on the Stiebel Eltron Mini?
The Stiebel Eltron Mini carries a 10-year leakage warranty and 3-year parts warranty. Complete warranty information is available online from Stiebel Eltron.
Can the Mini be connected to a water softener?
No — do not connect the Mini to a salt-regenerated water softener or a water supply of salt water. This is a manufacturer requirement per the official Stiebel Eltron spec sheet.
Can the Mini be mounted in any orientation?
Yes — the Mini can be mounted above or below the fixture with fittings pointing up or down, giving four possible mounting orientations. All units come pre-wired with a pigtail for the electrical connection.
Shop Stiebel Eltron Mini at PlumbersCrib.com
- Stiebel Eltron Mini 2-1 — 1.8 kW, 120V, 15A single pole, 0.32 GPM internally restricted
- Stiebel Eltron Mini 3-1 — 3.0 kW, 120V, 25A single pole, 0.5 GPM with aerator
- Stiebel Eltron Mini 4-2 — 3.5 kW, 240V, 15A double pole, 0.66 GPM with aerator
- Stiebel Eltron Mini 6-2 — 5.7 kW, 240V, 25A single pole, 1.0 GPM with aerator
Free shipping on all orders over $199. Contact our team or call 877-881-5501 Monday through Friday with sizing or spec questions.