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Ofen 2 (B-Stock)

-38%

€1.075,00

€1.741,67

Price excl. VAT

Color

White Black

1,000 W

Power

up to 50 m²

Area heated

up to 40 TH/s

Mining power

€ 562 per winter *

Bitcoin earnings

90 × 32 × 14 cm

Size

35 dB

Noise level

* Based on 4-year BTC average as of 01.2026

30-day-return

10,000+ Satisfied customers

Bought together

Premium Stand (Ofen 2 & Ofen 2 Pro)

Premium Stand (Ofen 2 & Ofen 2 Pro)

Premium Stand (Ofen 2 & Ofen 2 Pro)

€40,83

Wall Mount (Ofen 2 & Ofen 2 Pro)

Wall Mount (Ofen 2 & Ofen 2 Pro)

Wall Mount (Ofen 2 & Ofen 2 Pro)

€40,83

Product information

This is a brand new Ofen 2 from our previous production run. Technically this unit is identical to our standard model and it passed exactly the same test procedure before leaving our workshop. The only difference is on the outside. The housing shows small cosmetic flaws such as light scratches or minor blemishes in the finish. Each unit carries its own marks, so the photos show what to expect rather than the device you will receive.

None of this affects performance. You get the same heat output of up to 1,000 watts, the same coverage for rooms up to 50 m², the same quiet operation and the same scope of delivery. Warranty and support are unchanged.

A B-Stock unit is the obvious choice if the Ofen 2 goes into a workshop, a garage, a basement or a hobby room, where warmth and sats matter more than a flawless housing. This is a one time batch. We are not building any more B-Stock units, so availability ends with the last one on the shelf.

Power & ease of use

The Ofen 2 from 21energy offers a heat output of up to 1,000 watts and enables uncomplicated plug & play commissioning for particularly easy handling. This combination of performance and user-friendliness enables effortless use and optimum heat supply. Simple connection via WLAN and initial configuration with the 21energy-app takes just a few minutes. With the supplied operating instructions and a video tutorial, installation is very easy and child's play even for non-technical users.

Heating technology & noise level

Thanks to the innovative combination of convection and radiation, the heater provides even heat distribution. Even at it's high output, the Ofen 2 remains extremely quiet and ensures quiet operation with less than 45 dB at 1,000 watts, creating a pleasant room climate.

Design & mining power

Premium materials and powder coated steel make the Ofen 2 robust and durable. With a mining power of up to 40 TH/s and an efficiency as low as 20 J/TH, it also delivers impressive performance. On this Function over Form unit the powder coated surface shows small marks. The galvanized steel underneath is untouched, so robustness and corrosion resistance are the same as on a standard Ofen 2.

Protection & durability

The air and dust filters of the Ofen 2 provide effective protection against dirt deposits in the appliance, protecting the internal hardware and extending the life of the heater. The galvanized sheet metal provides durability and corrosion resistance, ensuring reliable use of the heater in a wide range of conditions.

Mining pool

The built-in Bitcoin miner is compatible with various mining pools and can also be used for solo mining.

Operating system

The Ofen 2 comes with the Braiins OS+ operating system, which offers automatic optimization and increases efficiency by up to 20%. This auto-tuning function enables improved cash flow and a higher hashrate of up to 20% with the same power consumption.

Savings potential

The savings potential of the Ofen 2 depends on individual energy costs and Bitcoin mining profitability. Calculate your individual heating cost savings now with our profitability calculator.

Have questions? Chat with us on WhatsApp

Ofen 2 (B-Stock)

Ofen 2 (B-Stock) - 21energy

Ofen 2 (B-Stock) - 21energy

Ofen 2 (B-Stock) - 21energy

Ofen 2 (B-Stock) - 21energy

Ofen 2 - 21energy

Ofen 2 - 21energy

Ofen 2 - 21energy

Ofen 2 - 21energy

Ofen 2 - 21energy

Ofen 2 - 21energy

Ofen 2 - 21energy

Ofen 2 - 21energy

Ofen 2 (B-Stock) - 21energy

Ofen 2 (B-Stock) - 21energy

Ofen 2 (B-Stock) - 21energy

Ofen 2 (B-Stock) - 21energy

Ofen 2 - 21energy

Ofen 2 - 21energy

Ofen 2 - 21energy

Ofen 2 - 21energy

Ofen 2 - 21energy

Ofen 2 - 21energy

Ofen 2 - 21energy

Ofen 2 - 21energy

Ofen 2 (B-Stock) - 21energy

Ofen 2 (B-Stock) - 21energy

Ofen 2 (B-Stock) - 21energy

Ofen 2 (B-Stock) - 21energy

Ofen 2 - 21energy

Ofen 2 - 21energy

Ofen 2 - 21energy

Ofen 2 - 21energy

Ofen 2 - 21energy

Ofen 2 - 21energy

Ofen 2 - 21energy

Ofen 2 - 21energy

1,000+ reviews

4.9

4.9

1,000+ reviews

4.9

4.9

10,000+ happy customers in 40 countries worldwide

4.9 out of 5 star rating verified on Trustpilot

Fast shipping from Austria with no customs in EU

Fast & expert multilingual support

What customers say

10,000+ satisfied customers and trusted by thousands of homes across Europe.

In the box

Ofen 2

1.000 W

Thermostat

Connect via Bluetooth

Power cord

1 m

Manual

Quickstart guide

Calculate your earnings

Calculate your earnings

Electricity

&

Heat & Bitcoin

Earnings

Choose heater

Choose historic Bitcoin value

You earn

€ 0,17 / kWh cashback

€ 808 / winter

How it's calculated = € 0,17 × 1,1 kW/h × 24 hours × 180 days

(Based on BTC average as of 01.2026)

Buy Ofen 2 Pro now Calculate personal earnings

Known from

Ofen 2 explained

Ofen 2 explained

Based on

Austria

Ofen 2 explained

Based on

Austria

Buy Ofen 2 Pro now

Pay securely via

Efficient by design

Hashboard Circuit Board

Quiet warmth

Whisper-quiet (~35 dB) so it blends into your living room.

Pays you back

Cashback

77 high performance processors turn electricity into warmth and Bitcoin.

Thermostat

Desired temperature

Set your desired temperature and the thermostat maintains it day & night.

Premium Materials

Built to last

Premium aluminium for long life and low maintenance.

Touch safe

Touch-safe design

Enclosed heating core and rounded edges, CE certified.

Hashboard Circuit Board

Quiet warmth

Whisper-quiet (~35 dB) so it blends into your living room.

Pays you back

Cashback

77 high performance processors turn electricity into warmth and Bitcoin.

Thermostat

Desired temperature

Set your desired temperature and the thermostat maintains it day & night.

Premium Materials

Built to last

Premium aluminium for long life and low maintenance.

Touch safe

Touch-safe design

Enclosed heating core and rounded edges, CE certified.

See it in action

Which heating saves you the most in {country}?

Based on

Switzerland

Ofen 2

Ofen 2 Pro

Oil heating

Oil heating

Gas heating

Gas heating

Heat pump

Heat pump

Purchase price

€1.741,67

Low upfront investment

Purchase price

€ 17,000

~8 x higher upfront

Purchase price

€ 15,000

~7x higher upfront

Purchase price

€ 15,000

~7x higher upfront

Seasonal costs

€ 4,290

Seasonal costs

€ 2,830

Seasonal costs

€ 2,060

Seasonal costs

€ 1,070

Seasonal savings

€ 3,300

Ofen 2 pays you back

Seasonal savings

€ 0

No savings

Seasonal savings

€ 0

No savings

Seasonal savings

€ 0

No savings

Net seasonal costs

€ 990

Net seasonal costs

€ 2,830

Net seasonal costs

€ 2,060

Net seasonal costs

€ 1,070

CO₂ emissions

Low

Environmentally friendly

CO₂ emissions

High

Unsustainable

CO₂ emissions

Moderate

Unsustainable

CO₂ emissions

Low

Environmentally friendly

Buy Ofen 2 Pro now

Pay securely via

Questions about Ofen 2

Can I operate the Ofen 2 with a LAN cable?

Yes, there is a USB port on the back of the Ofen 2, through which you can connect a LAN cable using a suitable adapter.

How can I control the Ofen 2?

The Ofen 2 can be controlled via the 21energy App. You can turn it on and off, adjust the heating levels, connect it to a thermostat, create schedules, and integrate it into your Home Assistant setup.

Do I need a Bitcoin wallet?

A Bitcoin wallet is required if you want to store the earnings from your mining pool yourself. Alternatively, you can send the earnings directly to an exchange and have them paid out in euros.

How do I receive the mined Bitcoins?

The Bitcoins mined by the Ofen 2 are first credited to your mining pool account. From there, you can transfer them to your Bitcoin wallet or directly to an exchange. More details can be found in theuser manual, section 5.4.

Do I need a good internet connection?

The Ofen 2 requires very little bandwidth (<1 Mbit/s). The most important factor is that the connection is stable and reliable.

Can the Ofen 2 be mounted vertically?

This is not recommended by default and should only be done if the Ofen 2 is placed and secured carefully and safely. The wall mount is designed only for horizontal installation.

Can I control my 21energy device with my smart home system?

Yes. The Ofen 2, Ofen 2 Pro and Port are all controlled through the 21energy App. For Home Assistant there is an official integration. Every other system can control the device through its open API. You will find the full interface specification in the app under "Automations".

Still looking for an answer?

Contact support

Good for the environment

The operation of the Ofen 2 can save up to 3 tons of CO₂ per year compared to conventional heaters.

Dive into the specifics

Discover our innovative Bitcoin heaters and find out how it helps you to heat more efficiently and save money.

21energy App Mockup

Set up in 3 minutes using the app.