Hashrate Heating: Running a Bitaxe Through an Aussie Winter

Many Australian homes still use portable resistive heaters during winter. Their cost depends on the appliance power, hours of use and the usage rate on the household’s actual electricity bill.

At an illustrative 35 c/kWh, a 2 kW heater costs 70 cents per hour. Check your bill rather than treating that rate as a statewide average.

What if those same watts also mined sats?

This is the “hashrate heating” pitch. It can offset part of the cost of heat you genuinely need, but it is not free heating and the mining hardware purchase price can dominate the calculation.

How hashrate heating works

All electric resistive heating is 100% efficient at the power-to-heat conversion: every watt you put in becomes roughly one watt of heat. Panel heater, oil column, fan heater — they’re all the same physics, differing only in form factor.

A bitcoin ASIC is also, from the thermodynamic perspective, a 100%-efficient electric heater. The only difference is that while converting the electricity to heat, it also performs useful computation that has a market value denominated in satoshis.

So a Bitaxe on your desk is:

• A 17 W space heater (negligible for heating, but fine for warming your hands)
  • A sats generator with a gross subsidy expectation of about AU$19.60/year at the 1 August 2026 snapshot used in our economics article

A rack of 20 NerdQaxe++ units is:

• A 1500 W space heater (equivalent to a small panel heater)
  • A sats generator with a gross subsidy expectation of about AU$1,568/year if all 20 units run continuously at the assumed 4.8 TH/s each

Actual noise, heat and electrical suitability depend on the miner, enclosure, fans and room. Measure rather than relying on a generic decibel or comfort claim.

The honest cost comparison

Let’s say you currently heat your living room with a 2000 W panel heater 4 hours per day in winter (Melbourne June–August, ~90 days):

Panel heater scenario:

• Power: 2000 W × 4 h × 90 d = 720 kWh
• Cost at $0.32/kWh peak: AU$230
• Heat delivered: ~720 kWh
• Sats earned: $0

Hashrate heater scenario (26 NerdQaxe++):

• Power: 1950 W × 4 h × 90 d = 702 kWh
• Cost at $0.32/kWh peak: AU$225
• Heat delivered: ~702 kWh (same)
• Gross subsidy expectation at the 1 August 2026 snapshot: about AU$84 over the 90-day window when the miners run only four hours per day
• Electricity cost after gross mining value: about AU$141, before pool fees, rejected work, downtime, hardware, ventilation and tax

The mining rack offsets part of the electricity cost in this example, but the earlier version of this article overstated the 90-day revenue by calculating it as though the miners ran longer. It also ignored the very large purchase cost of 26 miners.

That’s the pitch.

The elephant: heat pumps

The above comparison is rigged because it assumes resistive heating. An air-sourced heat pump (reverse-cycle AC) is 3–4× more thermally efficient than resistive because it moves heat rather than generating it.

Heat pump scenario:

• Power: 600 W × 4 h × 90 d = 216 kWh (COP of ~3.3)
• Cost at $0.32/kWh peak: AU$69
• Heat delivered: ~720 kWh (equivalent)
• Sats earned: $0

If you already have reverse-cycle AC (which most modern Aussie homes do), hashrate heating loses the comparison on cost efficiency unless you’re mining on very cheap power.

So the clean version of the argument:

• If you currently use resistive electric heating: a miner can offset some operating cost, but it is not an unambiguous win once hardware, pool fees, noise and control are included.
• If you currently use gas or reverse-cycle AC: compare delivered heat cost, equipment cost and emissions explicitly. A heat pump can deliver several units of heat per unit of electricity, so a resistive mining load may cost more for the same warmth.
• If you have rooftop solar: the calculation flips again — see our mining economics article for the solar maths.

The Tasmanian sweet spot

Tasmania is the best place in Australia to do this. Three reasons:

1. Cold climate: you genuinely need 5–6 months of heating per year.
2. Plan-specific tariffs: compare current Tasmanian offers and controlled-load eligibility rather than assuming a fixed rate.
3. Hydro-heavy grid: operational emissions still depend on time, imports and the accounting method; do not infer a precise percentage from this article.

A Launceston household could model a winter mining load, but whether it saves money or emissions requires the actual tariff, operating hours, displaced heating technology, hardware cost and grid-emissions method.

The practical setup

If this sounds like you, the practical setup looks like:

1. Utility room, garage, or cupboard with passive or exhausted airflow into the living space.
2. Electrical assessment — use the measured wall load, power-supply ratings, socket/circuit rating and all other loads on the circuit. Ask a licensed electrician before installing a continuous multi-device load; do not size a rack from a blog’s device count.
3. Smart plug or PDU for remote control — you want to turn the rack off if the pool goes down or the room overheats.
4. Ducting to push the hot air where you want it — flexible HVAC ducting from a hardware store is fine.
5. Acoustic treatment if near living areas — fan noise is the biggest complaint.
6. Smoke detector nearby — mandatory, not optional.

The philosophical version

There’s a broader idea called “Heatpunks” — the notion that miners are a load-balancing mechanism for the grid. They soak up excess solar in summer and excess hydro in winter, turning bitcoin into a physical battery for otherwise-curtailed electricity.

You don’t have to buy the philosophy. But if you’re in Hobart or Ballarat in July and you’re already paying AU$0.32 to warm your lounge room, the economic case is clearer than people realise.

Stack sats. Heat the house. Same watts.

Mining inputs use the dated 1 August 2026 snapshot in our economics article: about 902 EH/s and AU$89,692/BTC, block subsidy only. Recalculate with your tariff, measured wall power, actual operating hours and hardware cost.