Cloud storage vs a NAS at home: the five-year cost

Nearly every argument about cloud storage against a network drive at home is really an argument about two different shapes of spending. A subscription is a flat line: small, predictable, and infinite. Buying hardware is a spike followed by a shallow slope — a lot of money at the start, then a trickle of electricity, and eventually another spike when something breaks. People who prefer one shape rarely persuade people who prefer the other.

What can be settled is the arithmetic. Five years is the usual horizon: roughly how long a consumer NAS enclosure stays in software support, and roughly how long a set of hard drives works without becoming a gamble. This guide builds that figure from published prices, manufacturer power specifications and the current regulated electricity rate, and is explicit about every assumption — the assumptions are what decide the answer.

One thing to establish before any numbers: these are not the same product. A synced cloud folder and a drive in your house solve different problems, and if you only have one of them you probably do not have a backup at all. That argument is made properly in our guide to the 3-2-1 rule; what follows is about where one of those copies should live.

The short answer

• Under about 2 TB, the cloud wins on money and keeps winning. A 2 TB consumer plan runs roughly £100–£110 a year at published list prices. Five years of that is around £500 — less than a two-bay enclosure and two usable drives cost in autumn 2026.
• Above about 4 TB, hardware pulls ahead, but later than it used to. Cloud pricing scales in steps and gets expensive quickly above 2 TB. A NAS scales by adding capacity you buy once.
• Drive prices moved against the NAS this year. Independent price tracking put NAS-class drives up 55–66 % per terabyte between March and August 2026, blamed on datacentre demand. That pushes the crossover point further out than any comparison written in 2024 would suggest.
• Electricity is the part people overestimate. A two-bay NAS left on all year costs single figures to low double figures in pounds — real, but not the deciding factor.
• The honest tiebreaker is effort. With a NAS you are the storage administrator: updates, failed drives, and an off-site copy you still have to arrange. That labour has a value, and only you know what it is.

What the cloud actually costs

Consumer cloud storage is sold in tiers, and the tiers are the problem. You cannot buy 3 TB from most providers; you buy 2 TB and then jump to 6 TB or 12 TB. The prices below are the published UK consumer list prices at the time of writing, and are the sort of thing that changes without notice — check them rather than trusting this table in six months.

Three things in that table do most of the work. The 2 TB tier is the sweet spot in consumer pricing — about £54 per terabyte per year — and the tiers above it are no cheaper per terabyte, merely bigger. Microsoft 365 Family is the cheapest per-terabyte storage on the list by a wide margin, but only if you genuinely have five other people to share it with and each needs no more than a terabyte: it is six allocations, not a pool. And unlimited-backup products such as Backblaze Computer Backup are priced per computer and built to back a machine up, not to be a drive you browse.

Two easily forgotten costs attach to the cloud. Getting data out can be metered on object storage — B2 includes free egress up to three times your stored volume monthly, then charges $0.01 per GB — and restoring several terabytes over a domestic line takes days whatever the price. The model also depends on an upload link you may not have: filling a 2 TB plan over a 20 Mbit/s upstream takes about ten days of continuous transfer.

What a NAS actually costs

A NAS is four purchases pretending to be one: the enclosure, the drives, the electricity, and the replacement drive you will buy at some point during the five years. Only the first of those appears on the product page.

Enclosure prices for a current two-bay consumer unit sit broadly in the £250–£400 range excluding drives, and four-bay units well above that — though retailer spreads are wide enough to matter: the same two-bay Synology DS224+ was listed at £354.75 excluding VAT by one UK trade retailer and £532 by a consumer price tracker on the day this guide was written. That is a reason to shop rather than to quote a single figure, so the worked example below uses a round £300 and says so.

Drives are where the real money now is, and they need to be bought in pairs. A two-bay NAS holding two identical drives in a mirror gives you the capacity of one of them: two 8 TB drives produce 8 TB of usable space, not 16 TB. That is not waste — it is the redundancy that lets the box survive a drive failure — but it doubles the cost per usable terabyte, and it is the single most common mistake in back-of-an-envelope NAS maths.

Set that against five years of cloud at the same capacity. There is no 8 TB consumer tier, so the nearest comparison is iCloud+ at 12 TB — £659.88 a year, or about £3,299 over five years — or a pay-per-terabyte service such as B2 at roughly $83 per TB per year, which for 8 TB is around $3,300 over the same period. On those figures the NAS is the cheaper option at 8 TB by a factor of roughly three, and it is not close.

Run the same exercise at 2 TB and the verdict inverts. Two 4 TB drives, an enclosure and the electricity still cost most of £900, against £539 for five years of a 2 TB iCloud+ plan that also asks nothing of you. The enclosure and the redundancy overhead are close to fixed, so the smaller the capacity you need, the worse the hardware looks.

The drive market broke in 2026

Any cloud-versus-NAS comparison written before this year quietly assumed that hard drives get cheaper per terabyte over time, because for three decades they did. In 2026 they did not. eRacks Systems, which tracks the lowest advertised price per terabyte by drive line, reported that between March and August 2026 every line it follows rose: WD Red Pro up 66 % per terabyte, Seagate IronWolf Pro up 55 %, desktop Seagate Barracuda up 92 %, with enterprise lines up between 15 % and 48 %. Those are that tracker's figures, not our own measurements, and they attribute the squeeze to AI datacentre demand absorbing manufacturing capacity in precisely the 8–16 TB band where home NAS buyers shop.

Two consequences follow. The first is timing: if you were on the fence, the fence got more expensive, and the up-front spike in the hardware line is now taller than it was eighteen months ago. The second is a warning about the replacement drive in the table above. A mirror is only redundant if you can actually replace the failed half, and a failure in year four means paying whatever a drive costs in year four. Backblaze, which publishes quarterly statistics on a fleet of more than 350,000 drives, reported a 1.73 % annualised failure rate for the second quarter of 2026 against a lifetime figure of 1.41 % — small per drive per year, and not so small once you multiply by two or four drives across five years.

A related trap: some newer enclosures restrict you to a manufacturer-validated drive list, which in a tight market means you cannot simply buy whichever compatible drive is cheapest that week. Check the compatibility policy of the specific model, not the brand.

Electricity: smaller than people fear

This is the part of the comparison most often exaggerated in both directions, so here it is from manufacturer specifications. Synology publishes two figures per model: consumption in access mode and in drive hibernation. For the two-bay DS224+ those are 14.69 W and 4.41 W. For the four-bay DS925+ they are 37.91 W and 12.33 W. A realistic household average sits between the two, closer to hibernation than to access, because a home NAS spends most of the day doing nothing.

So the electricity for a modest two-bay unit is in the tens of pounds over five years, and for a busy four-bay unit it can approach the price of a drive. Worth including; rarely decisive. The rate used here is the Ofgem price cap unit rate for 1 October to 31 December 2026 — 26.32p per kWh — which is also the figure we used when working through what gadgets cost sitting idle. If your tariff differs, multiply the kilowatt-hours column by your own rate instead.

Where the lines cross

Pulling the halves together gives a rough rule. Below roughly 2 TB of usable capacity the cloud wins on five-year cost and keeps winning, because an enclosure plus mirrored drives never amortises over enough terabytes. Between 2 TB and 4 TB the two converge. Above roughly 4 TB the NAS wins clearly and the gap widens with every terabyte, because consumer cloud tiers stop getting cheaper per terabyte while drives keep getting bigger for a similar unit price.

Four assumptions move that crossover, and it is worth knowing which way each one pushes:

• How long the hardware lasts. Stretch the enclosure to eight years instead of five and the hardware line improves by a third. Bin it at three and the comparison collapses.
• Whether you count an off-site copy. A NAS alone is one copy in one building. If you add a cloud tier for the important subset — which you should — part of the subscription cost reappears on the hardware side of the ledger, as it does in the table above.
• Drive prices at the moment you buy. After 2026's rises this is the most volatile input in the whole calculation, and the one most worth waiting out if you can.
• Whether the cloud subscription is doing other jobs. A Microsoft 365 or iCloud+ plan bought for the software, the family sharing or the email carries the storage as a by-product, and then the marginal cost of the cloud copy is close to nothing.

The cost nobody puts on a price list

The honest case against a NAS is not financial: you become the administrator of a small piece of infrastructure. Firmware updates, the email saying a drive has developed bad sectors, knowing what to do when it arrives, remembering that a mirror copies deletions faithfully and so is not a backup, and arranging the off-site copy yourself. None of it is difficult; all of it is ongoing, and it lands on you at the least convenient moment, generally the moment a drive fails.

The case against the cloud is the mirror image. You are renting indefinitely at a price someone else sets; the tier you need can be repriced or withdrawn; access depends on an account that can be locked; and recovering several terabytes is bounded by your download speed rather than a cable. Neither of these is really a hidden cost — both are simply the thing you are buying.

Choosing on something other than price

Because the money is close in the middle of the range, it is reasonable to let something else decide.

Choose the cloud if your total is under about 2 TB, if you already pay for a plan that includes storage, or if your household has no appetite for maintenance.

Choose a NAS if you are above about 4 TB and growing, if you want fast local access to large video or photo libraries, or if you actively enjoy this kind of thing — a perfectly good reason, as long as it is stated out loud rather than dressed up as an economy.

Choose both if the data genuinely matters, which is what the 3-2-1 rule has been saying all along: the NAS as the fast local copy, a modest cloud tier for the irreplaceable subset, and no single building or account holding every copy. It costs more than either alone, and it is the only arrangement that answers the question people actually care about — not "how much is storage" but "what happens when this goes wrong".

Sources

• Apple Support — iCloud+ plans and pricing by country (50 GB, 200 GB, 2 TB, 6 TB and 12 TB tiers; UK prices)
• Microsoft — OneDrive and Microsoft 365 consumer plans and pricing (UK monthly and annual prices, storage per person)
• Backblaze — B2 Cloud Storage pricing ($6.95 per TB per month; free egress up to 3× stored volume, $0.01/GB beyond)
• Backblaze — Computer Backup pricing ($99 per year per computer, unlimited storage)
• Synology — DiskStation DS224+ specifications (14.69 W access, 4.41 W HDD hibernation; two bays)
• Synology — DiskStation DS925+ specifications (37.91 W access, 12.33 W HDD hibernation; four bays)
• Ofgem — energy price cap unit rates and standing charges, 1 October to 31 December 2026 (26.32p per kWh electricity)
• eRacks Systems — hard drive price-per-TB tracking, March to August 2026 (percentage rises by drive line; third-party price tracking, not our measurements)
• Backblaze — Drive Stats, methodology and published annualised failure rates across the production fleet
• Backblaze — Q1 2026 Drive Stats announcement (fleet size and quarterly failure-rate reporting)