21energy is an Austrian technology company that combines Bitcoin mining hardware with heating solutions—innovatively transforming everyday warmth into a source of earning potential. Designed to operate quietly and efficiently, their flagship “Ofen” devices deliver up to 42 TH/s in mining power while heating spaces up to 50 m², converting electrical input entirely into usable heat. This dual-purpose design allows users to stay warm and earn Bitcoin simultaneously.
One of the standout benefits is the potential for significant energy cost savings. By optimizing electricity usage through off-peak pricing and real-time monitoring via a user-friendly app, users can reduce their heating expenses by up to 50%. In regions with solar (PV) systems, surplus energy can be directed into mining rather than being fed back to the grid, providing earnings that can exceed traditional feed-in tariffs.
21energy emphasizes sustainability, noting that its heating solution can offset up to three metric tonnes of CO₂ annually compared to conventional electric heaters. Operating at a whisper-quiet 32 dB—comparable to a refrigerator—it’s well-suited for domestic environments.
The device’s compact and plug-and-play design makes setup straightforward. Additional features in development include smart thermostat integration, home-automation compatibility, and dynamic electrical pricing responses.
The company has garnered positive feedback from users across Europe, who praise both comfort and added profitability—especially when paired with personal PV systems. Many highlight the appeal of mining the world’s most important money network while staying warm in winter as a brilliant dual-purpose idea.
