Buy Refurbished Antminer S21+ 235 TH/s for Sale

The Refurbished Antminer S21+ 235 TH/s is a high-performance air-cooled Bitcoin ASIC designed for mining SHA-256 cryptocurrencies. Delivering a typical 235 TH/s hashrate with approximately 3,878W of power consumption, this S21+ configuration provides a substantial increase in computing capacity compared with earlier S21-generation hardware.

For mining operators looking to expand their SHA-256 infrastructure while controlling hardware acquisition costs, a professionally inspected S21+ can provide an attractive alternative to purchasing factory-new equipment. DeciMiners supplies new and professionally tested used cryptocurrency mining hardware for individual miners, hosting providers, data centers, and commercial mining operations.

The S21+ 235T is particularly suited to dedicated mining environments where reliable electrical infrastructure, adequate ventilation, and continuous operation can be maintained.

Antminer S21+ 235 TH/s Specifications

The specifications above are based on published S21+ 235T documentation. Actual performance can vary according to operating temperature, firmware, power conditions, and individual hardware condition. The published documentation indicates typical hashrate variation of ±3% and power/power-efficiency variation of ±5%.

235 TH/s Mining Performance for Professional Operations

With a typical hashrate of 235 TH/s, the S21+ 235T is designed for operators who need substantial SHA-256 computing capacity from an air-cooled ASIC platform.

Rather than focusing solely on the headline hashrate, miners should evaluate the machine based on its relationship between:

• Hashrate
• Power consumption
• Energy efficiency
• Electricity price
• Hardware cost
• Cooling requirements
• Expected uptime

At approximately 16.5 J/TH, the 235T version provides an efficiency improvement over the original 200T S21 specification of 17.5 J/TH. Bitmain’s published S21 specification lists the original 200T model at 3,500W and 17.5 J/TH.

This makes the S21+ an interesting option for miners evaluating hardware upgrades based on both computing capacity and energy consumption.

Understanding the S21+ 235T Power Requirement

Electricity is one of the largest recurring expenses in ASIC mining.

At a rated power draw of approximately 3,878W, continuous operation requires a substantial electrical supply.

A simplified calculation is:

3.878 kW × 24 hours = approximately 93.07 kWh per day

Over a 30-day period:

93.07 kWh × 30 = approximately 2,792 kWh per month

Estimated electricity expenses would therefore look approximately like this:

These figures are electricity-only estimates, not profitability projections. Actual consumption can vary with operating conditions, firmware, power settings, cooling requirements, and hardware condition.

For mining operators, knowing the local electricity rate is essential before purchasing any ASIC.

Is the S21+ 235T Profitable?

Mining profitability cannot be guaranteed because cryptocurrency markets and network conditions change continuously.

The potential economics of an S21+ depend on factors such as:

Bitcoin Price

A higher BTC market price can increase the fiat value of mined coins, while a lower price can reduce revenue.

Network Difficulty

Bitcoin difficulty adjusts as network mining conditions change. Increasing difficulty can reduce the amount of BTC generated by a fixed amount of hashrate.

Electricity Cost

Two miners operating identical hardware can have completely different economics if one pays $0.05/kWh and the other pays $0.15/kWh.

Mining Pool Fees

Pool fees reduce gross mining revenue and should be included when calculating expected returns.

Hardware Purchase Price

A lower acquisition cost can improve the economics of a mining deployment, although buyers should always consider hardware condition and warranty alongside price.

For this reason, prospective buyers should use a current mining profitability calculator with their actual electricity rate rather than relying on a fixed income estimate.

Why Consider a Professionally Tested Used S21+?

Buying refurbished ASIC hardware can make sense for miners who want to increase their hashrate without allocating the full budget required for new equipment.

A used machine can provide:

• Lower initial hardware expenditure
• Access to proven ASIC technology
• Faster deployment when inventory is available
• An opportunity to expand an existing mining farm
• Potentially attractive cost per TH/s

However, buying used equipment also requires more attention to the condition of the individual unit.

The most important questions are:

Has the machine been tested?

Are all hashboards operating correctly?

What hashrate does the unit actually produce?

How does the machine perform under sustained load?

What warranty is provided?

Are current photographs available?

These questions are especially important when purchasing multiple machines for a commercial deployment.

DeciMiners Testing and Inspection

At DeciMiners, product condition should be clearly communicated before a refurbished ASIC is purchased.

Depending on the specific unit, inspection and testing may include:

Exterior Inspection

The chassis, connectors, cables, and visible components are examined for physical damage or excessive wear.

Hashboard Verification

Hashboards are checked for proper operation and stable hashing performance.

Fan and Cooling Inspection

Cooling components are inspected to help ensure appropriate airflow during operation.

Power Testing

Power behavior can be evaluated during operation to identify abnormal consumption or instability.

Temperature Monitoring

Operating temperatures can be monitored during testing to identify potential cooling problems.

Hashrate Testing

The machine can be operated under load to verify that its performance is consistent with the expected configuration.

Final Inspection

The unit is checked before packaging and shipment.

Testing procedures may vary according to inventory and unit condition. Customers should request the available test information for the specific machine they intend to purchase.

This approach is more transparent than simply describing a used miner as “like new.”

S21+ 235T vs Earlier S21 200T

For miners comparing different S21-generation machines, efficiency is an important consideration.

The S21+ 235T provides approximately 17.5% more hashrate than the 200T model while improving the stated energy efficiency from 17.5 J/TH to 16.5 J/TH.

That doesn’t automatically make the S21+ the better purchase for every miner. The final decision should also consider acquisition price, electricity cost, warranty, condition, availability, and expected operating environment.

Is the S21+ 235T Suitable for Home Mining?

Although the S21+ is technically capable of being operated outside a commercial mining facility, its electrical and acoustic requirements should not be underestimated.

The published specification lists approximately 76 dBA at maximum fan operation.

That makes this type of ASIC significantly louder than normal household electronics.

A suitable installation should provide:

• Appropriate electrical capacity
• Proper circuit protection
• Strong ventilation
• Adequate intake airflow
• Hot-air exhaust management
• Reliable network connectivity
• Dust management
• Temperature monitoring
• Noise management

For most residential users, a dedicated mining room, garage, workshop, or properly engineered enclosure is preferable to placing the machine in a normal living area.

Experienced Individual Miners

Experienced miners with appropriate electrical infrastructure may also consider the machine for smaller-scale operations.

What to Check Before Buying

Before purchasing a used or refurbished ASIC, ask the supplier for information about the actual machine, rather than relying exclusively on generic manufacturer specifications.

Confirm the Hashrate

Ask for a recent test result where available.

Confirm Hardware Condition

Determine whether the machine has original or replacement components.

Ask About Hashboards

Confirm how many boards are functioning and whether repairs have been performed.

Check the Cooling System

Ask whether the fans have been tested and whether replacements are necessary.

Request Current Photos

For used equipment, actual photographs can help buyers evaluate the physical condition.

Understand the Warranty

Read the warranty terms carefully and confirm what failures are covered.

Confirm the Power Configuration

The S21+ uses a high-power electrical setup, so confirm that your facility can support the required voltage and current.

Warranty and Support

Warranty coverage is particularly important when purchasing refurbished mining hardware.

Before completing an order, customers should confirm:

• Warranty duration
• Covered components
• Return conditions
• Exchange policy
• Repair procedures
• Shipping responsibilities for warranty claims
• Conditions that may void the warranty

DeciMiners can provide the applicable warranty information for the specific unit before purchase.

This is especially important for commercial buyers purchasing multiple ASICs, where a clear warranty policy can help reduce operational uncertainty.

Frequently Asked Questions

How much hashrate does the S21+ 235T produce?

The 235T configuration has a typical rated hashrate of 235 TH/s. Actual hashrate can fluctuate depending on operating conditions and individual hardware.

What algorithm does the S21+ use?

The machine uses SHA-256 and is designed for cryptocurrencies including Bitcoin, Bitcoin Cash, and Bitcoin SV.

How much power does the 235T version consume?

The published specification lists approximately 3,878W at 25°C inlet air temperature.

What is the energy efficiency?

The stated efficiency is approximately 16.5 J/TH for the 235T version.

Is the S21+ 235T good for Bitcoin mining?

It is designed specifically for SHA-256 mining and provides 235 TH/s of computing capacity. Whether it is economically suitable depends on BTC price, network difficulty, electricity rates, pool fees, hardware cost, and operating expenses.

Is a refurbished S21+ worth buying?

A refurbished unit can offer lower upfront acquisition costs compared with new hardware. Buyers should evaluate the individual machine’s condition, test results, warranty, price, and expected operating costs before purchasing.

How loud is the S21+?

The published documentation lists noise of approximately 76 dBA under maximum fan operation.

Can the S21+ be used at home?

It can be operated in a residential setting if the electrical, ventilation, temperature, and noise requirements are properly managed. However, its power draw and acoustic output make a dedicated environment preferable.

Final Thoughts

The Refurbished Antminer S21+ 235 TH/s offers miners a combination of higher computing capacity and improved stated efficiency compared with the original 200T S21 configuration. Its 235 TH/s hashrate and 16.5 J/TH efficiency make it a compelling machine to evaluate for Bitcoin mining deployments where electricity cost and hardware acquisition price are carefully managed.

For buyers considering refurbished equipment, however, specifications are only part of the decision. The condition of the actual machine, hashboard performance, testing process, warranty, shipping arrangements, and supplier reputation should all be evaluated before placing an order.