Helium Hard Drives: Advantages, Disadvantages, Lifespan and How to Spot One

What is a helium filled hard drive?

A helium filled hard drive replaces the air inside with helium and is sealed so the gas stays in. Toshiba says it uses laser welding to permanently seal helium inside the MG10's 10-disk mechanics. Seagate describes the enclosure of its Exos X14 as hermetically sealed, with material and weld-width design that protects from helium leaks.

The makers use their own names for it. Western Digital calls its version HelioSeal, and its data sheet for the Ultrastar DC HC520 says the drive was previously known as the Ultrastar He12 and is part of the HC500 series of helium-filled hard drives. So He12 and HC520 are one product line under two names. Seagate lists a helium sealed-drive design as a feature of all four models on its Exos 24 TB to 32 TB data sheet.

Helium is not a property of a whole brand, and not always of a whole line. WD's Red Pro sheet, Seagate's IronWolf sheet and Synology's HAT3300 sheet all mix air-filled and helium models within one line, which matters when you compare two listings that look alike. The section on spotting a helium drive further down shows where to look.

Helium hard drive advantages, as the makers state them

Every advantage below comes from a maker's own data sheet or product overview. These are vendor claims, not our measurements, and the makers chose what to compare against.

Western Digital's sharpest claim compares its 12 TB helium Ultrastar DC HC520 with its own 8 TB air-filled Ultrastar drives: 50% more capacity, 52% less power per terabyte (watts per TB) and a 2.5 million hour MTBF rating, which WD calls 25% more reliable. That sets two different capacities from WD's own range side by side, so it shows what WD gained across a product step rather than an effect of helium on its own.

Lower power is the claim the makers repeat most. WD says the stable internal environment created by HelioSeal lets its Ultrastar DC HC590 deliver one of the lowest power profiles in the industry. Toshiba lists a lower operational power profile and power efficiency in W/TB as a key feature of the MG10. Seagate says the helium design of its Exos X16 delivers lower total cost of ownership through lower power and weight.

Toshiba adds a different kind of claim: the sealed design, together with corrosion-resistant electronics, mitigates life-time failure modes caused by air-borne pollutants and other environmental factors. That is a statement about what the seal keeps out. We have not found a document that attaches a failure-rate figure to it.

Air vs helium at the same capacity: two pairs from Seagate and WD

The fairest test of helium is two drives of the same capacity from the same line, one of each design. Two data sheets offer exactly that, and they do not tell quite the same story. Each maker quotes noise in dBA, but compare figures within a maker's sheet, not across makers.

Seagate's IronWolf data sheet has a 10 TB pair: ST10000VN000 is air-filled and ST10000VN0008 is helium. Both carry a 256 MB cache, so on that point the comparison is like for like.

WD's Red Pro data sheet prints seven models on one page and gives each a Drive Technology row: three are air and four are helium. The two 12 TB models are WD122KFBX, which is air-filled, and WD121KFBX, which is helium. This pair differs in cache as well as gas.

Read both tables as listed for these part numbers, not as a pure helium effect. What holds across both pairs is idle power: the helium model idles lower in each, 5.0 W against 7.8 W on the IronWolf and 2.8 W against 6.1 W on the Red Pro. Noise is mixed. The Red Pro helium model is much quieter at idle, while the IronWolf pair has the same idle figure and only a 2 dBA difference in seek. The Red Pro sheet also lists the helium model as lighter and gives both the same 2,000,000-hour MTBF, so on that sheet helium earns no MTBF advantage at 12 TB.

Helium hard drive disadvantages and open questions

We have not found a maker document that lists disadvantages of helium drives, so this section is about what the documents leave unproved, not about failures we have seen.

Keeping the gas in is a design concern by the makers' own wording: Seagate engineers the X14 enclosure against helium leaks and Toshiba presents laser welding as its answer. We have not found a document that gives a leak rate or a failure rate caused by leaks, so this page does not claim that helium drives fail by leaking.

Reliability does not settle the question on a data sheet either. The Red Pro sheet gives its air and helium 12 TB models the same MTBF rating. The one independent fleet comparison we cite, from Backblaze, leans towards helium once usage is matched, but its raw figures showed little difference; the lifespan section below sets out both halves.

Comparisons are easy to get wrong. WD's 50% capacity figure sets a 12 TB helium drive against an 8 TB air drive, and the Red Pro pair differs in cache as well as gas. Quieter running is not guaranteed either: the IronWolf 10 TB pair has the same idle noise figure for both designs. Two listings that share a capacity and a line name can differ in more than one way, and the price alone will not tell you which way.

Price is the question this guide cannot answer. It has no price table, so it makes no claim that helium drives cost more or less on Amazon.co.uk than air-filled ones.

Helium hard drive lifespan: what MTBF does and does not tell you

We have not found a maker document that states a service life in years for a helium drive. The maker documents we have found give MTBF ratings, AFR ratings and warranty terms. Synology says plainly that MTBF is not an estimate of product life, and WD that its ratings do not predict an individual drive's reliability.

In full, WD's data sheet for the Ultrastar DC HC550 says MTBF and AFR ratings do not predict an individual drive's reliability and do not constitute a warranty. Synology's HAT5300 data sheet says MTBF is not a guarantee or estimate of product life: it is a statistical value related to mean failure rates for a large number of products, which may not accurately reflect actual operation.

The nearest thing to a stated term is the warranty. On its Exos 24 TB to 32 TB data sheet, Seagate says its Exos drives are backed by a 5-year limited warranty and a 2.5 million hour MTBF rating, and the same sheet lists a helium sealed-drive design on all four models. A warranty length is not a forecast of when a drive will fail, and WD's wording above keeps the two apart.

For failures in service, the independent source we cite is Backblaze's post on helium and air drives in its own fleet, and it reads two ways. On the raw figures, the author wrote that there seems to be little difference in annualised failure rate based on whether drives contain helium or air. When the drives were in use a similar number of hours, though, the helium drives had a failure rate of 1.06% against 1.61% for the air-filled drives.

The post closes with the author's expectation, not a result: that once usage is normalised, the helium-filled drives Backblaze uses will continue to have a lower annualised failure rate than its air-filled drives, and that helium drives will eventually prove to have a lower AFR. One fleet is evidence about that fleet, not a forecast for the drive you buy.

So the honest answer on helium hard drive lifespan has three parts: we have not found a maker document that gives one; Seagate's helium-sealed Exos 24 TB to 32 TB models carry a 5-year limited warranty; and in one independent fleet, helium came out ahead once usage was matched, while the raw figures showed little difference.

How to tell if a hard drive is helium filled

The product name alone is not enough, because some lines contain both designs. These four documents show where the answer sits.

• WD Ultrastar: the part-number key on WD's HC550 data sheet marks helium with an H in the model number, against S for standard (air). In a WUH part number, the H is that letter.
• WD Red Pro: the data sheet's Drive Technology row is per model. At 12 TB, WD122KFBX is air and WD121KFBX is helium.
• Seagate IronWolf: the data sheet's Drive Design row is per model. At 10 TB, ST10000VN000 is air and ST10000VN0008 is helium; both 8 TB models on that page, ST8000VN004 and ST8000VN002, are air.
• Synology HAT3300: the data sheet lists the drive design as air for some capacities and helium-sealed for others within one product line.

The IronWolf pair is the trap to watch: ST10000VN000 and ST10000VN0008 differ by one trailing digit. A title that gives the capacity and line but drops or shortens the part number cannot tell you which design you are getting. Find the full part number on the listing, then find that exact part number on the maker's data sheet.

A listing that says helium is the seller's claim until the maker's sheet confirms it for that part number. The same goes for a listing that is silent: it is not evidence of air.

Which hard drives use helium? What the data sheets confirm

Maker data sheets confirm helium for the models and ranges below. It is not a complete list, and a line missing from it is not proof that the line is air-filled.

• WD Ultrastar DC HC520, formerly the Ultrastar He12, part of WD's HC500 series of helium-filled drives.
• WD Ultrastar DC HC590, which WD calls a high-capacity helium drive.
• Toshiba MG10, with helium sealed inside the 10-disk mechanics.
• Seagate Exos X16, with a helium sealed-drive design, and the Exos X14, whose sealed enclosure protects from helium leaks.
• Seagate Exos 24 TB, 28 TB, 30 TB and 32 TB, all four listed with a helium sealed-drive design.
• WD Red Pro WD161KFGX, WD142KFGX, WD141KFGX and WD121KFBX: the four helium models among the seven on one data sheet page.
• Seagate IronWolf ST10000VN0008, the helium 10 TB model.
• Synology HAT3300, at some capacities only.

Buying a helium hard drive on Amazon.co.uk

This guide has no live price table. Air and helium models share lines and differ by part number, so a table filtered by line would mix the two. Our pages for individual drive lines carry live Amazon.co.uk tables in pounds inc VAT, with a condition column on every row.

For WD's data centre drives, start with Ultrastar DC HC550, Ultrastar DC HC580, Ultrastar DC HC590 or the whole WD Ultrastar range. For Seagate and Toshiba, see Seagate Exos X24 and Toshiba MG10. On any of them, check the part number of the row you want against the maker's sheet before you rely on it being helium.

If lower idle power matters to you, both same-capacity pairs above point the same way: the helium part number idles lower on each sheet. Idle noise does not: it was lower for helium on the Red Pro pair and identical on the IronWolf pair, so check the sheet for the exact model if noise is the reason you are buying. If reliability decides it, the maker ratings do not separate helium from air and the independent evidence comes from one fleet, so weigh the warranty term and the maker's figures for the exact model.