The $900 Miner That Mined $156 of Bitcoin and Heated My Workshop

At 7:30 on a Tuesday evening in January 2025 I stood on my porch signing for a cardboard box with Colombian shipping labels, 42 pounds of used Bitcoin miner that hummed thru the styrofoam like somethin alive. The delivery guy asked what it was. A heater, I told him. That joke aged strangely.

I had paid $900 for a Whatsminer M30S++, 110 terahashes, snagged off a forum stranger who included a spare control board and a hand-written note saying she runs hot, watch the intake fan. My electricity costs 13.8 cents per kilowatt-hour. I had done the math. I wanna be clear, in retrospect, about what the math said: it said no. I snagged it anyway.

74 decibels in a workshop

The machine went into my workshop, a 300-square-foot shed forty feet from the house, and when I powered it on at 8:15 PM the sound was a central air unit arguing with a vacuum cleaner, 74 decibels at three feet, steady, industrial, committed. The shed warmed from 48 degrees to 68 in ninety minutes. That detail matters later. Everything about the six weeks that followed is downstream of one number printed on the label: 3,424 watts, around the clock, whether the machine found a block's worth of share or not, whether Bitcoin pumped or dumped or slept.

0.000062 Bitcoin a day

My share of the network, 110 terahashes outta something like 800 million, worked out to approximately 0.000062 BTC per day through a pool taking 1.5%, which at January 2025 prices near $60,000 meant about $3.70 of daily income against $11.32 of daily electricity. I wrote those two numbers on a whiteboard on the shed wall on day three, drew a line between em, and stared at the $7.62 gap like a man reading his own diagnosis. The whiteboard said negative $228 a month. The whiteboard was right, and I ran the machine for six more weeks anyways, cuz I had driven to that shed every evening to watch a number get worse and some part of me needed to see it happen in person.

the $475 electric bill with the bar chart

The February 2025 bill arrived at $611 total, $475 of it attributable to the shed by my meter math, and it came with a bar chart showing my usage against my neighbors' that made my household look like it was hosting a small smelting operation. My utility's autopay pulls from a high-yield savings account where I keep the household float earning 4.1%, and I remember the specific indignity of logging in to move an extra $400 over to cover a bill for a machine that had earned, at that point, 0.0019 BTC. About $115. My wife circled the bar chart in red pen. She is not the villain of this story. The bar chart is.

the workshop it kept at 68 degrees

Here is the twist that kept me sane. That February was cold, and the workshop, which I use evenings for woodworking, normally runs a propane heater at about $150 a month to hold 65 degrees. The miner held it at 68 for free, minus the part where it was not free, it was costing $228 net, but it was heat I would have partly snagged anyway, and the shed became the warmest room on the property. I chewed on the reframe for a while: a miner is a resistor, all waste heat by design, and if you have a room that needs heating, the electricity buys heat first and satoshis second. As a heater, the economics almost worked. As a Bitcoin strategy, the economics were a bonfire with a tip jar.

sold for $410 to a guy in Ohio

On March 21, 2025, I sold the machine for $410 to a man in Ohio whose electricity, he told me on the phone, costs 5 cents commercial rate, which is the entire sport in one sentence. My total tally: $900 in, $410 back out, 0.0026 BTC mined worth about $156 at the end, $475 of electricity against mayb $150 of heat I would have snagged. Net damage, approximately $260 for six weeks of noise and an education. I boxed it in the same styrofoam it arrived in and the porch got quiet. I miss the hum some evenings. I do not miss it $228 a month's worth.

the $900 my brother put in an index fund

My brother, who watched this entire saga with the patience of a man watching someone learn to juggle knives, had taken his own $900 in January 2025 and put it in a broad index fund, where it sat at approximately $1,010 by this spring while my adventure circled the drain and climbed back out minus tuition. He never said I told you so, which is its own kind of told you so. We talked through the final numbers over beers in April and he asked one question: would you do it again knowing? And honestly, knowing the shed would be warm and the whiteboard would be honest and the $260 would buy a story I now tell at every family gathering, possibly, once, cheaply. That is a feeling, not a plan. Feelings do not mine Bitcoin profitably at 13.8 cents.

the S21 I almost bought last winter

This past January, when the cold came back and the shed dropped into the fifties, I caught myself browsing listings for a used Antminer S21 at $1,400, doin the same math with the same 13.8 cents and watching it say no again, louder. I closed the tab. The propane heater came on, $150 a month, silent, and I transferred the difference into the boring savings account like an adult. Some equipment teaches you what it does. The Whatsminer taught me what I am: not a miner, not at these rates, in this decade. The porch box is gone, the whiteboard still says the two numbers, and every cold Tuesday evening in that warm shed I think about the machine that paid me $156 to learn it.