The useful combination is a computing load, a way to recover its heat, and a building that needs that heat. Thermal storage helps align their operating times.
What computing does the Node do?
The Heat21 approach uses SHA-256 computing. In our heating-cost model, this means Bitcoin mining: specialised hardware performs repeated cryptographic calculations as part of the process used to add blocks to Bitcoin's blockchain. This is a specific workload, rather than general-purpose cloud computing or AI training.
Mining produces heat as the hardware consumes electricity. Instead of treating that heat solely as something to remove, a heat-recovery system transfers it into a water circuit. Bitcoin proceeds and heat output are two separate outcomes of the same operation.
For background on the network, see Bitcoin.org's explanation of mining.
From electricity to stored heat
- Electricity runs the hardware.
The Node uses the building's electricity supply. You continue to pay your supplier under your own tariff.
- A cold plate transfers the heat.
Heat21 uses a hydronic cold plate: a water-based heat-transfer arrangement that carries heat away from the computing hardware towards a water-tank heat battery.
- The tank stores heat for later use.
The stored energy can serve heating and hot-water demand through a suitably designed system, so electricity consumption and heat delivery do not always have to happen together.
That separation creates flexibility. If the tank has enough usable heat, computing can pause during an expensive electricity period. The length of that pause depends on storage capacity, heat losses and the building's demand. Read more about electric heating with thermal storage.
Recovered heat must have a use. A full tank and little hot-water demand limit how much further heat a building can accept. A larger computing load is not automatically a better heating system.
What pays for the heat?
There are two potential cost benefits: buying electricity at suitable lower-price times, and offsetting some of its cost with computing revenue. Neither changes the unit price your supplier charges at the meter.
Mining proceeds vary with Bitcoin's sterling price, network difficulty, block rewards, fees and the hardware's efficiency. The Heat21 offset calculator lets you explore several of these inputs. Its result is an illustration per kWh of electricity consumed, not a guaranteed heating bill or a promise that the hardware will pay for itself.
The distinction matters when comparing alternatives. Recovering computing heat does not give the system a heat pump's ability to move additional heat from the air or ground. Its economic case rests on useful heat recovery, operating times and revenue. Our heating-cost guide explains what a fuller comparison must include.
Where does wasted wind fit in?
Wind curtailment means reducing wind generation that could otherwise be available. Network limits can prevent electricity reaching the places that need it, even when demand exists elsewhere. NESO explains how these network constraints arise.
Our related research project, CurtailCoin's wind-curtailment tracker, lets you explore reported curtailed energy by date and wind farm, alongside estimates of potential Bitcoin output for selected mining hardware. Those estimates describe a hypothetical use of energy, not Bitcoin that was actually mined or profit after all costs.
Flexible heating is one possible use for electricity at suitable times. Helping a particular grid constraint also depends on location and network conditions: a cheap tariff alone does not prove a home is using wind power that would otherwise have been curtailed. The live tariff-shifting demonstration shows the separate, practical question of when an electric heater consumes power.
Start with the building
Heat21's current focus is homes considering an alternative electric heating approach, including properties where a heat pump may be difficult to accommodate. Suitability needs an assessment of the particular building, rather than a decision based on its fuel type alone.
- Heat demand: how much heating and hot water is needed, and when? Summer demand can be very different from winter demand.
- Space and integration: where could the Node and storage fit, and how would they connect to the existing heating system?
- Supply and operation: what electrical capacity, connectivity and operating constraints need to be assessed?
- Costs and resilience: what happens during maintenance, downtime or a period of low compute revenue?
For an initial discussion, share your location, existing heating type, recent energy use and any known space constraints with Heat21. These details make a feasibility discussion more useful than a headline savings figure.