21energy Bitcoin Heaters
Bitcoin miners that double as space heaters — the 21energy Ofen series.
21energy, based in Austria, makes Bitcoin miners designed to double as space heaters. Its Ofen series turns the heat that every ASIC produces into useful warmth for your home or workshop, while mining BTC at the same time.
If you want to capture the heat instead of venting it, 21energy is a unique option. Buy an Ofen from Bull Miners — or, if you'd rather mine at scale without the heat at home, host a standard Bitcoin miner with us on cheap power instead.
21energy miners for sale
2 models. Buy & ship, collect, or host any machine on cheap green power.
BitcoinHost your 21energy miner from $0.018/kWh
A 21energy miner is loud, hot and power-hungry — which is why most owners don't run it at home. Buy it here and we'll rack, power, cool, monitor and maintain it 24/7 across 12+ global facilities on cheap green power. You own the hardware and every coin it mines is paid straight to your own wallet.
- Transparent power from $0.018/kWh — no hidden pass-through
- 99.9% uptime with 24/7 monitoring and maintenance
- Air, hydro and immersion cooling supported
- You keep 100% of mined coins — paid to your wallet
21energy — frequently asked questions
How does a 21energy Bitcoin heater work?
The Ofen is a Bitcoin ASIC packaged as a space heater — the electricity it uses to mine BTC is converted almost entirely to heat, which warms your room instead of being wasted.
Is a Bitcoin heater profitable?
It earns BTC while heating, so if you'd be heating anyway, the mining reward effectively offsets your heating cost. Pure profitability still depends on BTC price and your electricity rate.
How much does a 21energy Ofen cost?
21energy Ofen units typically range from around fifteen hundred to a few thousand dollars depending on hashrate and heat output. Live pricing is shown above.
Can I host a 21energy miner instead?
Heaters are designed for home use, but if you want pure mining at scale we can host standard Bitcoin miners for you on cheap power — ask us for the best option.
Is the Ofen quiet enough for a home?
21energy designs the Ofen to be quieter than industrial miners so it can live in a home or office. Check each listing for noise specs.
Are 21energy units new with warranty?
Yes, new units with warranty unless a listing states otherwise.