ASIC Heat Output Table 2026: How Much Heat a Miner Produces and What You Can Actually Do With It

Every ASIC miner is a space heater that happens to produce Bitcoin. This is not a criticism. It is a thermodynamic fact. Nearly 100 percent of the electrical energy consumed by a mining ASIC converts to heat. The hash computation is the economic purpose. The heat is the physical output. For anyone considering heat reuse, the first thing you need is an honest table of how much heat each common miner actually produces, at what temperature, and with what airflow characteristics.

Manufacturer spec sheets give you a wattage number. That is a start. But wattage alone does not tell you whether the heat is useful for your application. A 3,000-watt miner and a 3,000-watt convection heater produce the same total thermal energy, but they deliver it differently. The miner produces a concentrated, high-velocity stream of hot air at 50 to 65 degrees Celsius. The convection heater produces gentle warmth distributed broadly. That difference matters enormously for heat reuse planning.

The 2026 ASIC Thermal Reference Table

These figures are drawn from manufacturer specifications, independent testing reports, and our own observations where available. All figures assume standard air-cooled operation at stock settings in a 25-degree-Celsius ambient environment.

Bitmain Antminer Series

MicroBT Whatsminer Series

Notes on These Figures

Wall power varies with input voltage and power supply efficiency. A miner rated at 3,500W at the wall may consume 3,400W or 3,600W depending on your supply voltage and the PSU efficiency curve. The thermal output tracks the actual consumption, not the rated figure.

Exhaust temperature ranges are wide because ambient matters. In a 15-degree room, the exhaust is cooler in absolute terms than in a 30-degree room. The delta-T across the miner stays roughly consistent (25-35K for most units), but the absolute exhaust temperature shifts with intake conditions.

Airflow figures are approximate. Manufacturers rarely publish precise CFM data. These are derived from fan specifications and independent measurements. Fan speed, dust accumulation, and altitude all affect actual airflow.

Noise figures are measured at one metre in free air. In an enclosure, reflected sound may be higher. In a well-insulated enclosure with duct-connected exhaust, perceived noise at the greenhouse is significantly lower.

What the Numbers Mean for Reuse

Single Miner Applications

A single modern ASIC in the 3,000 to 3,500-watt range produces heat equivalent to a medium domestic space heater. Practical applications at this scale:

• Small greenhouse frost protection. One miner can maintain above-freezing temperatures in a well-insulated greenhouse of 12 to 18 square metres through moderate winter conditions. See our calculator guide for the specific math.
• Workshop heating. A single miner heats a small workshop or shed effectively. The noise is the main constraint in occupied spaces.
• Water pre-heating. Running miner exhaust through a simple air-to-water heat exchanger can pre-heat domestic water by 10 to 20 degrees, reducing boiler demand. This requires a purpose-built or adapted heat exchanger and some plumbing.
• Drying applications. Hot, dry air from a miner is useful for drying herbs, seeds, or firewood. The high airflow and elevated temperature make it genuinely effective for this.

Multiple Miner Applications

Scaling from one to four miners takes you from supplemental heating to primary heating capacity for larger spaces:

• Two miners (6,000-7,000W): Primary heating for a 20 to 35 square metre greenhouse in moderate climates. Supplemental in cold climates.
• Three miners (9,000-10,500W): Approaching the heating demand of a 40 to 60 square metre greenhouse in moderate winter conditions. District-scale heat contribution for very small buildings.
• Four miners (12,000-14,000W): Equivalent to a small residential heating system. At this scale, noise management and electrical infrastructure become significant concerns.

Efficiency Tiers

Not all miners are equally useful for heat reuse. Newer, more efficient models produce fewer watts of heat per terahash of computation. Counterintuitively, for heat reuse, older and less efficient models produce more heat per unit of hash rate, making them better heaters per bitcoin earned.

However, less efficient miners also earn less bitcoin per watt, which affects the economics. The ideal heat-reuse miner is one that:

• Produces enough heat for your application
• Earns enough bitcoin to justify its electricity consumption
• Can be purchased at a reasonable price (often older models are cheaper)

The sweet spot in 2026 for pure heat-reuse economics tends to be one generation behind the latest, where hardware costs have dropped but the machines are still profitable enough to run.

Exhaust Temperature and Usefulness

Raw thermal output in watts tells you the total energy. But the temperature of that energy determines what you can do with it. Heat at 60 degrees Celsius is far more useful than the same wattage at 30 degrees because it can drive a larger temperature differential in your application.

High-temperature exhaust (55-65 degrees C) is useful for:

• Water pre-heating through air-to-water exchangers
• Direct space heating in adjacent rooms
• Short-duct greenhouse heating with minimal temperature loss
• Drying applications

Medium-temperature exhaust (40-55 degrees C, after some duct loss) is useful for:

• Greenhouse bench heating
• Root zone warming for propagation
• Preventing condensation in storage spaces
• Soil warming for early-season beds

Low-temperature exhaust (below 40 degrees C, after long duct runs or mixing) is useful for:

• Ambient temperature buffering in lightly insulated spaces
• Preventing hard frost in unheated structures
• Marginal contribution to large-volume heating

The practical takeaway: keep your duct runs short and insulated to preserve the temperature advantage. Every metre of duct and every degree of heat lost reduces the usefulness of the remaining energy.

Seasonal Considerations

Miner heat output is constant regardless of season (assuming the miner runs at the same settings year-round). But the usefulness of that heat varies dramatically:

• Winter: Maximum value. Heat demand is high, and mining heat directly offsets fuel costs.
• Spring/Autumn: Moderate value. Useful for overnight frost protection and temperature smoothing.
• Summer: Zero or negative value. The heat must be rejected to the outside, costing additional cooling energy. See our coverage of summer mode operations for strategies.

This seasonal mismatch is one of the fundamental challenges of greenhouse heat reuse. Your miner heats a space that only needs heating for part of the year.

Cross-Referencing With Your Heating Bill

The most practical way to assess whether ASIC heat is worth capturing is to compare it against what you currently spend on greenhouse heating.

If your heating bill for the season is 800 euros and you could offset 60 percent of it with miner heat, that saves 480 euros. If the duct infrastructure costs 300 euros, it pays for itself in the first season. If the infrastructure costs 2,000 euros, it takes over four seasons, and by then the mining hardware may be obsolete.

Run the numbers for your specific situation. The heat reuse calculator provides the framework. This table gives you the thermal inputs.

Further Reading

For layout and duct routing specifics, see Bitcoin Mining Greenhouse Heating in 2026. For the broader heat reuse picture, start with Bitcoin Mining Heat Reuse.