Used Antminer KS5 Pro 21TH/s Kaspa Miner – Tested KHeavyHash ASIC
Antminer KS5 Pro, 21 TH/s on kHeavyHash for Kaspa: 3,150 W and exactly 150 J/TH as published by Bitmain. Tested used unit, ~75 dB, 220 V class — not a 110 V machine. Single-algorithm hardware, and this page is straight about what that risk means.
Price:
$329.99
- Condition graded per unit: new, tested working, refurbished or as-is
- Warranty and returns stated per unit, not per store
- Ships UPS Ground within 7 business days
Description
The Antminer KS5 Pro is Bitmain’s kHeavyHash machine for Kaspa (KAS), rated at 21 TH/s for 3,150 W — exactly 150 J/TH. This is a tested used unit. The most important thing to understand before you buy one has nothing to do with the spec sheet: this is single-algorithm hardware. It mines kHeavyHash chains and nothing else. It cannot be repointed at Bitcoin, it cannot be converted to SHA-256, and its resale value is tied to Kaspa’s fortunes rather than to mining generally. That concentration is the real risk on this purchase.
Bitmain's published specification
| Hashrate | 21 TH/s on kHeavyHash |
|---|---|
| Power consumption | 3,150 W |
| Efficiency | 150 J/TH — 3,150 W ÷ 21 TH/s, so the two published figures are exactly consistent with each other |
| Algorithm and coins | kHeavyHash only — Kaspa (KAS) and other kHeavyHash chains |
| Input voltage | published sources disagree here — some list 220–240 V AC, others 220–277 V. We are not going to resolve that by picking the flattering one. Either way it is not a 110 V machine; ask us and we will read the rating label off this actual unit |
| Noise | ~75–76 dB from 4 fans |
| Dimensions and weight | 430 × 195 × 290 mm, 15.8 kg |
| Network | Ethernet · Released: February–March 2024 |
What 150 J/TH does and does not tell you
Do not compare that against a Bitcoin miner’s 20–35 J/TH and draw a conclusion. Joules per terahash only compares machines running the same algorithm — different algorithms have different difficulty, different block rewards and different coin prices, so the units happen to match while the meaning does not. The comparison worth making is against the other KAS and kHeavyHash hardware we carry, never against an S19.
Whether it earns depends on Kaspa network difficulty, the KAS price and your electricity cost on the day you switch it on. All three move constantly, which is why no earnings figure appears on this page. Run your own numbers with our guide to specs and running costs.
Condition
Sold as a tested used unit in clean condition, verified before shipping. Expect cosmetic wear consistent with hardware in service since 2024. This listing states no warranty term, so we are not going to imply one — ask us for the test method, the DOA window and the return terms in writing before you order and we will confirm them.
What’s in the box
Whether a PSU ships with this unit is not stated in the listing, so this page does not claim it does. The KS5 Pro is normally supplied with an integrated supply, but on used stock that is worth confirming rather than assuming. Ask us about PSU, cord and plug standard and we will put the answer in writing.
Siting it
3,150 W continuous, ~75 dB and 15.8 kg. It needs a 220 V-class circuit, genuine airflow and somewhere the noise is nobody’s problem. The siting rules are those of an industrial Bitcoin miner — the algorithm is different, the machine is every bit as loud.
Who should buy this
Someone who specifically wants Kaspa exposure through hardware and accepts that a single-algorithm miner rises and falls with one chain. If you want the broadest resale market and the most flexible redeployment, SHA-256 hardware is the safer asset.
Questions buyers ask about this machine
Will this run on a normal household outlet?
No. This machine needs a dedicated 220–240 V circuit. A North American 120 V household outlet will not run it under any adapter or configuration. At 3,150 W it draws about 13.1 A at 240 V, so the circuit wants a 20 A breaker — continuous loads are sized at 125% under the NEC, and a miner is the textbook continuous load. Size for your actual supply voltage, not ours: the same load on a 208 V feed draws more current, not less. Have an electrician confirm the supply before the pallet arrives.
What will it cost to run?
That depends on your electricity rate, so here is the part we can state exactly: at 3,150 W running 24/7, this machine burns about 2,268 kWh a month. Multiply that by your own all-in rate per kWh — including delivery charges, not just the supply rate — to get your monthly power bill. We do not publish profitability figures, because they change with difficulty and price every day.
How loud is it?
~75–76 dB from 4 fans — about as loud as a household vacuum cleaner running continuously, and it does not stop. This is a garage, workshop, outbuilding or hosted-facility machine, not something to put in a room where people live or sleep.
What condition is it in, and what does that grade mean?
This is second-hand stock. We describe it the way we found it: tested working means it ran on our bench at the stated hashrate, refurbished means it was also cleaned, re-pasted or had parts replaced, and as-is means it is sold without a working claim. The grade for this unit is stated in the description above; where a listing states no grade, it says so rather than implying one. Cosmetic wear — dust, scratches, label marks — is normal on hardware that has been mining and is not a fault.
What should I check the day it arrives?
Photograph the pallet or box before you open it, keep the packaging, and run the 48-hour acceptance test straight away. Freight claim windows are short, and a fault found on day two is a conversation while a fault found on day thirty is an argument. Our own six-step bench procedure is published in full, so you can repeat exactly what we did.
Shipping cost for this exact item, and how warranty and returns work here, are answered in the Shipping & buying tab on this page. Anything else, ask a person on +1 (781) 577-0377 or ns@ingmining.com — we would rather talk before you buy.
Is it worth repairing, and does used still win at this price?
There is no KS5 Pro hashboard on our shelf, there is no Bitmain S19 or S21 part that fits one, and you should price that in before you buy. What we do stock for this machine is diagnosis, not repair: a IceRiver KS-series fixture at $249.99 and a K3L hashboard tester at $459.99, which lists KS3 and KS5 coverage. Both cost most of what the miner costs. On a single KS5 Pro the correct plan is to buy it tested and never plan to repair it — which is why this unit was benched before it was listed and why what our grades mean spells out what tested-working commits us to. Fans and cooling are the failures worth watching; heat and dust are what kill kHeavyHash machines exactly as they kill SHA-256 ones, and why mining hardware fails covers that half.
This is the strongest argument for buying used that exists, and it is not about the discount. Single-algorithm hardware is a bet on one chain, and a bet you make with $329.99 is a different bet from the same one made at new-machine money. A SHA-256 miner that stops paying gets redeployed or resold into a deep market; a KS5 Pro that stops paying is worth what Kaspa says it is worth that week. Buying used is how you keep the capital at risk proportional to the certainty you have — and when it is time to exit, we buy used miners. used vs new ASIC miners sets out the two gates any used purchase has to clear; note that its J/TH crossover maths compares machines on the same algorithm only, so use it for the electricity gate here, not for a cross-algorithm comparison.
Parts prices are our own shelf, read on 16 August 2026, and they are parts only — we do not publish a bench labour rate, so nothing here pretends to be a fitted price.
Related hardware and where this sits in the store
Other used and refurbished units currently on the floor:
- Used Antminer S19k Pro 120TH Bitcoin Miner – VNish 130TH Tune
- Bitmain Antminer S19 110TH/s Bitcoin Miner – Refurbished and Boosted
- Used Antminer S19k Pro 115TH/s – Tested, Braiins OS Boost to ~125TH/s
The other KHeavyHash machines on the floor are all new rather than used, and all of them are bigger: the Antminer KS7 40T, the IceRiver KS7 30T and the IceRiver KS7 Lite 4.2T.
Categories: Used ASIC miners, XTM/ALEO/KAS/Dash/CKB Miner, Air Cooling and Bitmain Antminer.
Deciding whether kHeavyHash is the right algorithm at all? Kaspa miner vs Litecoin miner measures this machine against the other altcoin miner on our shelf, the Antminer L9, using the one figure that compares across algorithms — the electricity rate at which each machine stops earning. It does not flatter this one: on 30 July 2026 the KS5 Pro broke even near 5.3 ¢/kWh against the L9’s 9.2 ¢. If Kaspa specifically is what you want, that page also works out the rate below which mining KAS beats simply buying KAS.
Where this listing sits
This one is on the used and refurbished shelf. It is second-hand hardware. The grade for this specific unit is stated in the description on this page — and where a listing states no grade, it says so rather than implying one.
What our grades mean
These are the only words we use, and each one means a specific thing. They are not interchangeable and we do not soften them to move stock.
| New | Unused stock. Factory sealed unless the listing says otherwise — “new, open box” means exactly that, and the listing will say it. |
|---|---|
| Tested working | Second-hand, and it ran on our bench at the hashrate the listing states. We measured it; we are not repeating what the last owner told us. Expect cosmetic wear. |
| Refurbished | Tested working, plus work done: cleaned, thermal paste and fans dealt with, failed components replaced. The listing says what was actually done to that unit rather than using the word as decoration. |
| As-is / for parts | Sold with no working claim at all, at a price that reflects it. Buy these to repair or to harvest. If a listing says as-is, assume it does not hash until you have proved otherwise. |
| Untested | We have it, we have not powered it, and we are not going to pretend we did. Rarer than as-is and always stated explicitly. |
What a grade here does not mean
- Cosmetic wear is not a fault. Dust, scratches, scuffed labels and discoloured plastics are normal on hardware that has been earning. We photograph what we have; if the pictures matter to you, ask for more and we will take them.
- A grade is not a warranty. Warranty terms are stated per listing, never per store — see the Shipping & buying tab. A tested-working grade describes what the machine did on our bench, not what we owe you in six months.
- A boosted hashrate is not a spec. Where a unit ships on tuned firmware we say so and we give the factory figures too, because overclocking raises power faster than it raises hashrate — a tuned machine is less efficient per terahash than stock, not more.
- We will not invent a grade to fill a field. If a unit came in without history and has not been through the bench, its listing says that.
How the grade gets decided
A used-hardware seller who will not tell you how they test is asking you to take the grade on trust. Ours is published: the six-step bench procedure every machine goes through, and the five measurements that get recorded — per-board hashrate, chip count, measured wall power rather than the nameplate figure, hardware error rate, and temperature under sustained load. When it reaches you, run the 48-hour acceptance test straight away, while the freight claim window is still open.
Buying second-hand for the first time? How to buy a used ASIC miner without getting burned is the long version, written from the repair bench rather than from a spec sheet.
Additional information
| Weight | 32 lbs |
|---|---|
| Dimensions | 20 × 15 × 12 in |
Our Related Products
Related products
-
Add to WishlistAdd to Wishlist
-
Add to WishlistAdd to Wishlist
-
Add to WishlistAdd to Wishlist
-
Add to WishlistAdd to Wishlist
