A Space Heater from a Bitcoin AntMiner

In February, 2024, my co-worker sent me a picture of an ASIC S9 AntMiner at the local pawnshop. I couldn’t get the idea out of my head, so I started searching for resources and finally went it bought for $120 (they had it listed for $139.99, but I offered less). Suprisingly the owner did know some things about Bitcoin and had mined Ethereum in the past.

Joining the Ocean Pool

I decided on the Ocean pool, though it’s small after the promise of Lightning payments in the future. I did look into Braiins Pool, but just went with Ocean pool.

My Miner Info

The original ASIC dashboard. I’ve since changed this to Braiins OS to use less Watts.

My Hashrate from the Ocean dashboard. It is only 5 Th/s until I log in to Braiins OS and click start BosMiner.

Motivations

I found a full tutorial how to turn the ASIC into a space heater . I decided it’d be a fun chance to learn about mining and to let my kids learn more about electronic hardware.

The S9 was created in 2019. So it is way out of date and it’s efficiency is no match for the s19s or the brand new s21 .

Economics

The In the charts on the page for the S9 , you can see that the projected revenue does not match the electricity expenses.

Current

• Network Hashrate (7D) 651.05 EH/s
• Block Rewards (24h) 6.40 BTC The halving is estimated for April 20, 2024 (today as I write this), so the Block Rewards will be 3.125 after that.

https://www.coinwarz.com/mining/bitcoin/calculator

My Rewards So Far

As of 4/19/24, after running for about a month, I have 0.00028359 BTC (or 28359 SATS about $18 worth (28359 / 1554) : https://usdsat.com/) .

The estimated earnings went to 7250 Sats after the Halving on April 20th.

Costs

• $120 for the ASIC S9 Miner
• $5 3d printed adapter by a friend
• $32 2 Noctua NF-P14s fans
  • these reduced the sound level immensely
• Electricty: this is very rough but about $2.80 W per hour to 19.2 KWH per day * .15 per KWH = $2.88
  • $2.88 per day X 30 = $86.44

At current prices, I spent about $243.40 and am waiting to gain $18 worth of Sats.

Update on 5/21/2024

• I used 547 extra Watts in April, it was about $2 more per day on average
• after almost 2 whole months, I’ve made 49,683 SATS for around $170 in electricty.
• It’s getting warm out, so it’s time to shut it off. I don’t need extra heat.
• I need to setup Bolt12 Lightning so that I can get my payment.
• I’m happy with the experiment and will consider bringing it back online when it’s cold out again.

I knew I wouldn’t make money, but at least my basement is a bit warmer :-)

Update on 1/2/2025

My miner was offline for December. Something happened and I thought it was dead. I was also seeing the red fault light on the back and on the hasboards.

I couldn’t give up, so I bought new cords on Amazon for around $13.

On December 23, 2025 I got an on-chain payout of 74,397 sats. At first, I thought I had lost it (since I never figured out getting a CoreLND Bolt12 offer running), but then saw it was on-chain. They must payout after awhile if no activity. There was about 12 blocks found by the Ocean pool while I was offline. Ocean network hash is up to 3.56 Eh/s

After resetting it in the AntMiner interface and then Braiins, then setting the pools up again. It’s running again at 10.5 TH/s, 97 degrees Celsius, 900 W, 85.5 W / TH/s.

Before this issue I was hashing at up to 12 to 15 TH/s. I’ve found that I have to try different settings in Braiins until it stops restarting. I wish I had written down what I had before, as I can’t get it back to that perf. Maybe one of my boards was harmed?

Current Braiins Settings on 1/2/2025

Stats: around 11.4 TH/s, 90 to 96 degrees Celsius (it’s mid 60s F, downstairs), 900 W, 78.4 W / TH/s (after running a few hours).

Performance Tab: Enable Automining : 900 Power target, Enable Dynamic Perf Scaling

Fans: Manual (with this is on it kept restarting, I think my fan sensors aren’t working correctly)

I should do more research on setting things correctly for more hash, but the temp is staying below 100 C, so that’s the main goal (keep it running).

New Power Adapter Fan makes a lot of difference

I decided to spend another $15 and buy the Bitcoin Sessions recommended fan for the power adapter Noctua NF-A6x25 FLX, Premium Quiet Fan, 3-Pin (60mm, Brown) (see the instruction video above). The plugin has 3 pins, so I cut some wires, taped them together to adapt to that.

It’s much quieter than before.

Before any new fans example on YouTube . I couldn’t stand it and run it at this noise level.

My miner with the new 2 Noctua NF-P14s fans

My miner with the new 2 Noctua NF-P14s fans and the new power adapter fan

Alternatives

The Avalon Nano 3 is only $99 (as of 4/24/2024). I think more and more options will come out as time goes on.

Check out Softwarm LLC on X to see interesting posts on how people are using Bitcoin miners to heat spaces and earn Bitcoin.