On-Premise NAS vs Cloud Backup: A Cost Comparison

When it comes to protecting your business data, UK organisations face a fundamental choice between two approaches: storing backups on a local Network Attached Storage (NAS) device in the office, or backing up to a cloud service over the internet. Both have legitimate advantages, and the right choice depends on your specific requirements for capacity, recovery speed, budget, and resilience.

However, many businesses make this decision based on incomplete cost analysis. The upfront purchase price of a NAS device appears cheaper than years of cloud subscription fees, leading to the assumption that local backup is the more economical option. In reality, the total cost of ownership for a NAS device — including hardware replacement, maintenance, electricity, and the critical cost of off-site resilience — often exceeds cloud backup over a five-year period.

This guide provides a detailed, like-for-like cost comparison between on-premise NAS and cloud backup for UK SMEs, covering not just the obvious costs but the hidden expenses that many businesses overlook.

Understanding the Two Approaches

Before comparing costs, it is important to understand what each approach involves and what it delivers.

On-Premise NAS Backup: A NAS device is a dedicated storage appliance connected to your office network. Backup software on your servers and workstations sends data to the NAS over your local network, typically on a scheduled basis (nightly full backups with hourly or daily incremental backups). The NAS stores multiple backup versions, allowing you to restore data from different points in time. Popular NAS manufacturers for business use include Synology, QNAP, and Buffalo, with devices ranging from compact 2-bay units to large rack-mounted systems.

Cloud Backup: A cloud backup service stores your data in secure, geographically distributed data centres operated by the backup provider. Backup software (an agent) installed on your servers and workstations encrypts your data and transmits it over the internet to the cloud. The data is stored redundantly across multiple data centres, providing protection against any single point of failure. Popular cloud backup providers for UK businesses include Datto, Veeam Cloud Connect, Acronis, and Barracuda.

The True Cost of On-Premise NAS

Many businesses calculate the cost of NAS backup as simply the purchase price of the device. This dramatically underestimates the true cost. Let us break down every cost component over a five-year period for a typical UK SME with 2TB of backup data.

Hardware Purchase: A business-grade 4-bay NAS with RAID redundancy — such as a Synology DS923+ — costs approximately £500-£600. Four 4TB NAS-rated hard drives (such as Seagate IronWolf or Western Digital Red) cost approximately £100-£130 each, totalling £400-£520. Initial hardware cost: approximately £900-£1,120.

UPS Protection: A NAS should be connected to an uninterruptible power supply to prevent data corruption from power outages. A basic UPS suitable for a NAS costs £100-£200, with battery replacement needed every 3 years at approximately £60-£80. Five-year UPS cost: approximately £160-£280.

Hard Drive Replacement: NAS drives running 24/7 have an annual failure rate of approximately 2-4%. Over five years with four drives, you can expect to replace one or two drives. Replacement cost: approximately £100-£260.

Electricity: A 4-bay NAS consumes approximately 30-50 watts continuously. At UK electricity rates of approximately 28p per kWh, this equates to roughly £75-£120 per year, or £375-£600 over five years.

Setup and Maintenance: Professional configuration of backup software, RAID setup, monitoring configuration, and network integration typically costs £300-£500 for initial setup. Ongoing maintenance — firmware updates, drive health monitoring, backup verification — adds approximately 2-4 hours per month of IT support time. At typical MSP rates of £80-£120 per hour, this adds £1,920-£5,760 per year, or £9,600-£28,800 over five years.

Hardware Replacement: At the end of five years, the NAS hardware typically needs replacing. Budget another £900-£1,120 for the replacement device, plus data migration costs of £300-£500.

The True Cost of Cloud Backup

Cloud backup costs are more straightforward and predictable. The primary cost is the monthly subscription, which is based on the volume of data protected and the features included.

For a UK SME with 2TB of backup data, a business-grade cloud backup service typically costs between £100 and £200 per month, depending on the provider and features. This price includes all storage, redundancy, encryption, monitoring, and the backup software agents. There are no hardware costs, no electricity costs, no drive replacements, and no hardware refresh cycles.

Setup costs for cloud backup are lower than NAS, typically £300-£600 for agent installation, policy configuration, and initial seeding. Ongoing management is also simpler, as the cloud provider handles hardware maintenance, storage scaling, and infrastructure monitoring. Your IT provider's involvement is limited to managing backup policies, monitoring success/failure alerts, and performing test restores — approximately 1-2 hours per month.

The most significant cost advantage of cloud backup, however, is what it includes that NAS does not: off-site storage, geographic redundancy, and disaster recovery capability. A NAS device sitting in the same office as your servers provides no protection against physical disasters. To achieve equivalent resilience with a NAS-based approach, you would need a second NAS at a different location with replication configured — essentially doubling your hardware and maintenance costs.

Recovery Speed: The Critical Difference

Cost is important, but the ultimate measure of a backup solution is how quickly it can get your business back up and running after a data loss event. This is where the comparison becomes nuanced.

For individual file recovery — a single document, a few emails, a specific database — cloud backup recovery times are typically comparable to NAS. The file is downloaded from the cloud and restored within minutes to hours depending on size.

For full system recovery — restoring an entire server after a hardware failure or ransomware attack — NAS has a speed advantage because the restore happens over your local network at gigabit or multi-gigabit speeds. Restoring 500GB from a local NAS over a gigabit connection takes approximately one to two hours. Restoring the same 500GB from the cloud over a 100Mbps internet connection takes approximately twelve hours.

However, modern cloud backup providers offer solutions that bridge this gap. Datto, for example, provides instant virtualisation — the ability to boot a backed-up server image directly in the cloud within minutes, allowing your staff to continue working while a full restore to local hardware happens in the background. This changes the recovery equation from "how fast can we download" to "how fast can we get people working," and cloud solutions with instant virtualisation often get businesses operational faster than NAS-based restores.

The Ransomware Factor

The rise of ransomware has fundamentally changed the backup calculus for UK businesses. Ransomware attacks specifically target backup systems — modern ransomware variants actively search for and encrypt NAS devices, network shares, and backup repositories before encrypting the primary data. If your NAS is connected to your network and accessible via standard file shares, it is vulnerable to the same ransomware that encrypts your servers and workstations.

Cloud backup provides significantly better protection against ransomware because the backup data is stored outside your network, protected by the provider's security infrastructure, and typically uses immutable storage that cannot be modified or deleted by ransomware. Even if an attacker compromises your network and encrypts everything on-site — including your NAS — your cloud backups remain intact and accessible for recovery.

Some NAS devices offer ransomware protection features such as immutable snapshots, but these are only effective if properly configured and tested. The NCSC guidance on ransomware specifically recommends maintaining off-site, offline, or immutable backups as a defence against ransomware — a requirement that cloud backup satisfies inherently while NAS-based backup requires additional measures to achieve.

The Hybrid Approach

For many UK businesses, the optimal solution is a hybrid approach that combines local NAS backup with cloud backup, providing the speed advantages of local storage with the resilience advantages of off-site cloud storage. This approach fully satisfies the 3-2-1 backup rule: your primary data on your servers (copy 1), a local backup on the NAS (copy 2, different media), and a cloud backup in a UK data centre (copy 3, off-site).

Hybrid backup solutions such as Datto SIRIS and Veeam with Cloud Connect are designed specifically for this approach. The local appliance provides fast backup and recovery for day-to-day needs, while automatically replicating backups to the cloud for disaster recovery. If the local appliance is destroyed by a physical disaster or encrypted by ransomware, the cloud copy provides a complete recovery path.

The cost of a hybrid approach is higher than either option alone, but for businesses where data loss would have severe consequences — financial, regulatory, or reputational — the additional cost is justified by the comprehensive protection it provides.