Hi Everyone, this is my first post here and a writeup rough draft for this project. My plans are to open source it and hopefully be a resource to anyone that wants to do this in their homes.
Please ask any questions in the comments. Please give feedback if you have any. This is not complete yet. Your questions will make it into the final writeup. I am not a writer, nor a technical writer. I am a discount engineer and want every home in the world to have a system like this

I heat my 100 yr old home with Immersion Bitcoin Mining

This journey started in November of 2023. This house is almost a century old and was heated a hydronic boiler and radiator system. For those that aren't familiar, a hydronic radiator system is one that pumps hot water around pipes throughout the house, to let heat off from cast iron radiators. The system I had/have works great, but I couldn't help being annoyed a burning oil, to only get heat.
Bitcoin mining machines get hot. Very hot. Hot enough to heat a whole home. The goal of this project was to eliminate my heating oil bill by capturing and reusing the waste heat from these machines.

Hydronic Systems

Hydronic Systems are an older technology that holds up incredibly well. It's efficient, quiet, and a nice cozy heat.
There are 5 parts to every hydronic system:
  1. Heat source(s)
  2. Pipes containing water
  3. Radiators in the spaces you want heat
  4. Pump(s) to circulate the water
  5. Thermostats/aquastats, for control and safety
  6. (Optional, but nice) Zone controllers for more control
The system is filled with tap water, and that water will forever circulate around until it is drained.
As for the heat source, it can be anything that gets hot.
Common heat sources include:
  • Natual gas boilers
  • Oil Boilers
  • Wood systems
  • (Now) Bitcoin Miners

The Calculations

Heat

The existing oil boiler can produce about 125,000 BTU/h of heat. This was my rough ballpark number. However, this current system runs intermittently. So it would run for about 15 minutes, stop for 30, and repeat. While this works fine, the temperature swings 5-8 degrees between heating cycles.
There exists a direct conversion of Watts to BTUs:
1 Watt = 3.41 BTU/h
So with this number in mind, I began to look at machines on the market and what power they output. I ended up with two S19k Pros for their increased efficiency and constraints within my budget.
When running in standard mode, one machine will consume ~2760W from the wall, which is ~9,411 BTU/h of heat; and when running overclocked, one machine pulls ~3600W, which is ~12,276 BTU/h of heat. Because of thermodynamics, all energy consumed by the processor will eventually be dissipated as heat.
So since I now knew I had a range of ~18,000 - 24,000 BTUs of heat, is this enough to heat a home? Turns out, yes.
Even though the boiler can produce a much higher output, the short bursts of that output give a similar area under the curve to the miners, which are on all the time when in heating mode.

Fiat Costs

The oil plan I used to have was an anual usage, divided by 12, and then paid monthly. So in winter, when more deliveries would come in, I would pay the same as I would in the summer, when I would get maybe 1 a season. So the negative cost I needed to match or beat was ~380 per month, then this project would still be worth it, as I am now at least stacking sats and learning by doing.
Mining at home will be entirely dependent on your electricity rates. These rates consist of a generation charge and a distribution charge. Most commonly refer to this in the combined form as "Cost per Killawatt Hour" or c/kWh. My distribution charge of 0.084c/kWh was fixed, nothing I could do to lower it. However, I was able to find a way to bring my generation charge down to 0.07c/kWh. So my current electricity rate is $0.154c/kWh. If you are familiar with the mining scene, this is quite high. But recapturing the heat is an incredibly efficient action. What was waste is now useful, while getting Sats. It's paying once, and receiving two uses for the same watt. This efficiency boost allows home mining operations to be competitive with commercial. Heating is a sunk cost for a home, and now it is possible to monetize it.
Remember, the goal is not "profit" in fiat terms, the goal is to get sats for a bill you are paying anyways.

Heat Exchangers

There are multiple forms of heat exchangers, but for this type of installation, brazed plate heat exchangers are the ideal type.
Heat exchanger sizing is quite difficult, it is possible to do all of the math involved, but the general rule is bigger = better.
Source HBIM channel: https://www.youtube.com/channel/UC9dv60_ORGjNpdHYQ2GDR2Q Aside: Bob from this channel is a Godsend. He has so much knowledge and this project would not have been possible without him. I was constantly referencing his videos! Thank you Bob!!

Design Considerations

  • Do you want to run the miners all the time? or only when heat is needed?
    • yes, heat exhaustion is needed (more sats)
    • no, simply turn them off (less sats)
  • Are you only trying to heat living space? Or also tap water?
  • How insulated is your home?
  • Do you have any existing infrastructure you are working around, or are you starting from scratch?
  • Is your electrical pannel big enough?

The System

For my system, I wanted to have 3 heat exchanger stages.
First stage, use the heat for the tap water (it is a great feeling to be washing clothes/dishes/hands, and showering with Bitcoin). The second stage uses the heat in the hydronic radiator system. And the third stage is outside exhaust.
For the first stage, I went all out and used a 100 plate heat exchanger. I am sure the engineers in the comments are laughing at this, given its way oversized, but this was simply a part in my learning journey. When heating, I am able to warm the tap water up from 55 degrees F, to 130 degrees F. This water travels prewarmed into the boiler. The result is the boiler is on for way less, or not at all for some heat loads. Remember, the miners can only heat immersion fluid comfortably to around 60-70 degrees C. I try not to push them that high, as they run less efficiently the higher the temperature is.
For the second and third state, I used 40 plate heat exchangers. This was from the reccommendations "here" and they seem to be sized just right.
For the indoor radiator system, I had to integrate this new heat source to work in parrallel with my current boiler. I wanted to be able to have either heat source, that way there is redundancy and the boiler can assist the miners if it is too cold outside. Here is a diagram of how this looks simplified. "Diagram" . There are also safety system in place for the miners.
For example, if the miners are circulating heat through the house and the boiler circulator pump also turns on, the mining system will automatically exhaust, as to not put the heat from the boiler into the immersion system and heating up the machines.
For the exhaust side, this is its own seperate hydronic system. Instead of only water, it is filled with a glycol/water mixture, so that it will not freeze in the winter. This system has its own circulating pump which goes to the Fog Hashing radiator outside. This radiator has its own power and temperature sensors, and it is able to control the speed of the fans to match what is needed for the heat input. To make this system easier for myself, I utilized PEX-A piping, which was nice to not need to solder copper pipes. One of the other safety systems is a temperature controller on the final output of the oil line. If this ever becomes too hot, the system will turn on the exhaust if it is off.

Electrical

The electrical side of this project has three parts.
  • High voltage AC (240v)
  • Low Voltage AC (24vac)
  • Low Voltage DC (24v)
The low voltage side was simple. A doorbell power supply is 24vac and perfect for this application. I used 4 cable speaker wire to carry the 24vac to both control boxes. Each control box has a 24vac side, and a full bridge rectifier to convert it to DC. The DC components include fans, lights, thermometers, and USB buck converters.
To control the 240v to each miner, I used 10/2 romex cable and put each miner on its own dedicated 30 Amp circuit breaker. Each high voltage cable goes into its own 24vac 240v Air conditioning contactor. Think of this as basically a very large relay. The closing and opening of the contactor is controlled via the oil circulation pump in the fog hashing tank. There is a current sensing relay that is closed if the pump is on and open if the pump is off. When the oil pump turns on, the contactors close and high voltage power is supplied to the miners, turning them on. There is a quirk with the fog hashing tank. In the event of a power outage, when power is restored, the pump will not automatically turn on. This is why I added the current sensing relay and the contactors. Otherwise, the power would be restored and the miners would cyclically turn on, overheat, and turn off again.
To control the pumps, I utilized a standard Taco switching relay for hydronic systems. The low voltage control box contains all logic with no micro controllers. There is a standard analog thermostat in the middle of the house which controls the circulation pump on the bitcoin miner side. If this pump is on, then the exhaust pump is off, since I want to keep all the heat inside. However, if the oil becomes too hot, both pumps will turn on, protecting the miners. If the thermostat is off, then only the exhaust pump is on, and the heat is directed outside.

(Electrical Cont) Home Assistant

To monitor the temperatures of everything, I made a 12 input temperature sensor with an ESP8266 running ESPHome. The ESP has 12 DS18B20 Temperature probes connected to it, with one probe being on every input and output (yes I know some are shared). this data is pumped into Home Assistant and I can view and graph live temperature data.

What I spent

This project was quite expensive, but I was able to save so much by doing all of the labor myself. No, I did not have any experience with plumbing, soldering copper pipes, or maintaining my hydronic system before this project. I was familiar with mains electrical systems and have added outlets and switches in places, but that's about it. My point is that anyone with an internet connection can learn and do anything. Leverage it as the tool none of your ancestors had.
Most of the cost was the miners themselves and the Fog Hashing kit. Could you probably make a cheaper tank and find a cheaper radiator? Maybe, but good luck. You will put a lot of time into it and this kit was able to be perfectly adapted to this, even though this is not what it was made for. The rest of the cost was plumbing. This included all tools, fittings, pipes, pastes, etc. I have never soldered a copper pipe before this project, if I can do it, you can too

Conclusion

You are correct. If I had used the dollar amount of this project to buy bitcoin, I would be head and up in bitcoin terms. I would have had more bitcoin simply buying it. I knew that going into this and that wasn't the point. The point was to monentize waste, to learn all of these new skills, to further decentralize the network, to stick it to the commercial grade miners, and to write up a cool post about it. The skills I learned doing this project are worth more to me than the bitcoin I could have bought. I now have the ability to do many other projects around the house without having to call contractors. I am able to save by working for myself.

Photos!

Absolutely fascinating. I plan on buying a house in a cold climate in the next few years and I want to do exactly this. And then spread the tech far and wide. How cold does it get where you are? Do you have good insulation? What kind of ambient temperatures are you getting in any given room with a radiator? Are you getting enough sats to reduce your electricity bill and if so by how much e.g. 5%, 50%? Inspirational, I will be going through all this with a fine tooth comb in due course, I need to know what I should look out for when buying a house.
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Thank you for your questions!
How cold does it get where you are? I am in the north east of the USA. The coldest it gets during the winter is single digits at the worst. Most times around 20s. (Freedom units)
Do you have good insulation? Nope! This house has none. The rooms I have renovated have a bit but the rest of the house has nothing haha.
What kind of ambient temperatures are you getting in any given room with a radiator? Since the heat is essentially free/very cheap, I leave the heat up higher than normal, maybe around 73 on the first floor. I have to exhaust the heat at night to sleep since it gets as hot as 75-80 degrees upstairs.
Are you getting enough sats to reduce your electricity bill and if so by how much e.g. 5%, 50%?
The sats stacked fluctuate around break even or +/- 10% profit loss. But remember from the post, as long as I am losing the equivalent or less dollars than the old oil bill, it is "positive" to me. If it's break even, then its free heat. If its less then its really cheap heat. And if its positive then I am being paid to heat and shower :)
Your questions will make it into the next version of this writeup, thank you!
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Again, totally amazing. Can't wait to get stuck into this. Thank you for your responses, no further Qs at this time! That is very warm given there is no insulation and the time of year where are.
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This was my favorite part:
My point is that anyone with an internet connection can learn and do anything. Leverage it as the tool none of your ancestors had.
This is the most necessary advice in existence right now. Thanks for setting such a great example.
I'm curious about the miners. You talk about overclocking them -- my instinct would be, if anything, to underclock them, since you want those bad boys to run for as long as humanly possible, right? Miner failure will be a way bigger PITA than the benefit of squeezing every last bit of hashrate out of them.
Also, what's the noise situation?
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Great questions!
I run them overclocked for the extra heat. They run slightly less efficiently this way but it doesn't matter since the house needs to be warm. I also want to stack the max amount of sats I can before the halvening. Once that hits I will run them as efficiently as possible since the heat will be exhausted anyways. The overclock setting I'm using now is built into the stock firmware so I'm thinking it's within the machines capabilities.
As far as the noise, I ran them stock while building the system. It was equivalent to about 2 vacuum cleaners running all the time. Now that they are immersed, the only sounds are the pumps and they are essentially silent!
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Super cool, thanks for clarifying.
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The skills I learned doing this project are worth more to me than the bitcoin I could have bought. I now have the ability to do many other projects around the house without having to call contractors. I am able to save by working for myself.
Music to @Natalia’s ears. Careful though advertising your new-found skills, you might earn too many satoshis on the side consulting for people contemplating similar builds.
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Oh yes! more skills one learned, the more free he / she is:) and then you can def help others and sharing your first hand experience!
well done @NicoHeatingBTC
Amazing! The most comprehensive post about heating with miners that I ever came across.
The point was to monentize waste, to learn all of these new skills, to further decentralize the network, to stick it to the commercial grade miners, and to write up a cool post about it.
Yes, you've nailed all these points. Thank you for the post and welcome to SN.
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Thank you!
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This is really cool but I always wondered how this compares to just using a heat pump. Did you do any comparisons?
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Great question!
In terms of electrical efficiency, the heat pump wins by a long shot. They are able to move much more heat energy than they consume in electrical, it's crazy. So heat pumps will use by far less energy. If these machines weren't mining bitcoin, they would be essentially 4,000 watt space heaters.
Heat pumps being able to do heating and cooling is great. Once someone figures out how to use bitcoin mining for air conditioning then thats when things will really pop off haha. I will probably install heat pumps at some point for cooling since I have no AC, but for now the main goal was mining :)
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This is the content I like to see on SN !
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This is the content that send us over outdated reddit
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Lets GOOO, @DarthCoin saw my post!!!!
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Impressive, don't forget the advantage of acquiring pristine non-kyc sats, which come at a premium nowadays.
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Correct! I did not consider the premium in my cost analysis, just spot cost of coin. But you are right. It's nice to be able to DCA through my electric bill :)
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Good call out! The dachshund ones work better than the worm ones, right?
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If there are dune-worm ones i'll literally cry from joy 😂
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this is just spectacular, it would never have occurred to me, I guess you already had experience in Bitcoin mining right?
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Way back in like 2014 I had a usb Antminer U2, LOL. I never got any of the sats I mined with it but it was neat. Other than that, no mining experience until this project and doing the research. I was freaking out the day I hit "buy" on the miners, since that meant I had to commit all the way till the end. This whole project was trial by fire haha
I would love to work in the mining industry, if anyone sees this post and wants to get in contact!
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Hyperbitcoinization will require ASICs heaters in every house. You support the system the system supports you
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This will be one of the most obvious transitions. We will look back and wonder why we paid to heat things without bitcoin miners. Thank you!
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When newcomers ask me about mining I tell them about "free heaters" use case if they can handle noise
We all around recycle paper, metal, glass, etc. now it time to recycle heat
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This is a godlike post. Thank you for the writeup.
I hope one day to follow in your footsteps. First step: home ownership
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Thank you! I am very blessed to own and be able to do this project. Timing is so important in the real estate market
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No way, shut the front door! Awesome!
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Bitcoin = be your own bank and now repair man!
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Thank you!
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This is awesome. Thank you for sharing all of the the pics+details. I tipped you 1000 sats. You're the the first I've ever tipped that large on SN. You earned it.
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I am honored, thank you!
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Well done! Hope your electricity rates will go down. Mine are zero due to the sun. Anyways you’re definitely helping bitcoin in many ways! One thing is for sure BTC does good for the planet and humanity.
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Thank you! I have been researching solar but my place is not great for it. I'd also have to cut down my neighbors trees and it would cost probably double what I spent on the project to do. Once this stuff gets cheaper and better, then I will definitely try this. Or if I move and do a v2 system
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Great read
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Thank you!
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hats off to you sir. well done
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Thank you!
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How can someone not like bitcoin ? All the best to you ;)
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Thank you!
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Awesome work! Have you gotten all the kinks worked out and if so what do you figure you'll need to do and how often as far as maintenance goes?
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Great question, this has been running nonstop for a bit over a month now. SO FAR it has been fine. I have a few of the tiniest leaks in some spots but nothing for concern yet. The machines themselves should be fine, everything is solid state, no moving parts, and they at at temperature 24/7 which is prefered.
If it ever gets too cold or I need to do maintenance, my old oil boiler is in parallel and can take over
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If Carlsberg did first posts… 🍺 this would be it.
What an amazing blueprint. Even better seeing the photos and pipework from the action.
There’s something about seeing bare copper pipes that makes me wish they were visible more often.
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Thank you! I need to try this beer now haha
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How did you manage the noise (dB) of the miner? These are supposed to be oppressively loud...wondering how you solved that?
That is quiet impressive. Wish you all the best!