How Much Does a Synology NAS Cost to Run 24/7?

Synology

A Synology NAS may run for five years or longer, which means the price you pay for the enclosure and hard drives is only part of its real ownership cost.

Electricity consumption, drive count, heat output, cooling, and noise all matter when a NAS operates 24 hours a day. These factors become increasingly important as you move from a compact two-bay DiskStation to larger four-, five-, and eight-bay systems.

The good news is that most desktop Synology NAS models consume relatively modest amounts of electricity. But the difference between running a small two-bay system and an eight-bay NAS continuously can add up over several years.

Understanding those differences can help you choose the right Synology without buying more hardware and creating more heat and noise than your workload actually requires.

How Much Power Do Current Synology NAS Models Use?

Synology publishes power measurements for its DiskStation models under both active-access and HDD-hibernation conditions.

Several current Plus models illustrate how consumption increases with system size:

Model	Drive Bays	Access Power	HDD Hibernation	Noise
DS225+	2	16.98 W	6.08 W	19.6 dB(A)
DS725+	2	20.41 W	7.87 W	17.9 dB(A)
DS425+	4	28.25 W	6.10 W	21.6 dB(A)
DS925+	4	37.91 W	12.33 W	20.5 dB(A)
DS1525+	5	44.56 W	13.63 W	22.6 dB(A)
DS1825+	8	60.10 W	18.34 W	23.8 dB(A)

These figures show why bay count alone does not determine electricity consumption. CPU platform, number of installed drives, networking, system design, and workload also matter.

Still, the overall pattern is clear: larger systems generally require more power.

What Does That Electricity Actually Cost?

Watts are difficult to translate into an ownership decision until you convert them into dollars.

A simple calculation is:

Watts × 24 hours × 365 days ÷ 1,000 = annual kWh

Then multiply annual kWh by your electricity rate.

For illustration, assume electricity costs $0.15 per kWh and the NAS continuously consumes its published access-power figure.

The DS225+ at 16.98 watts would consume approximately 149 kWh annually, costing about $22 per year.
The DS925+ at 37.91 watts would consume approximately 332 kWh, or about $50 per year.
The DS1825+ at 60.1 watts would consume approximately 527 kWh, costing about $79 per year.

Over five years, those illustrative electricity costs become approximately:

DS225+: $112
DS925+: $249
DS1825+: $395

Your actual cost will vary significantly because a NAS does not remain at one fixed load continuously, electricity rates differ by location, and workloads change throughout the day. The calculation is useful primarily for comparing architectures.

HDD Hibernation Can Reduce Consumption, but Don’t Assume You’ll Always Reach It

Synology’s hibernation numbers are substantially lower. The DS925+, for example, is rated at 37.91 watts during access but only 12.33 watts with its HDDs hibernating. The DS1825+ drops from 60.1 watts to 18.34 watts. That sounds like an easy opportunity to reduce electricity use.

In practice, however, a busy NAS may not spend much time in HDD hibernation. Background services, computers accessing shares, Synology Drive synchronization, media applications, containers, surveillance workloads, backup jobs, indexing, monitoring, and other activity can keep storage active.

A NAS used exclusively for occasional home backups may spend significant time idle. A business file server serving employees throughout the day will behave differently. Therefore, don’t calculate your entire five-year ownership cost using the hibernation figure unless your workload realistically allows the drives to remain asleep.

Hard Drives Contribute to Power, Heat, and Noise

The NAS enclosure is only part of the system. Each additional spinning hard drive introduces power consumption, vibration, and heat. An eight-bay NAS populated with eight enterprise HDDs will naturally behave differently from a two-bay NAS containing two quieter drives. Drive characteristics matter too.

High-capacity and enterprise-class HDDs may produce more noticeable seek noise than users expect from looking only at the NAS manufacturer’s dB rating.

That is particularly important if the DiskStation will sit:

On a desk
In a home office
In a bedroom
Near a conference room
In a living area
Inside a quiet studio

In those environments, drive seek and vibration may be more noticeable than the system fans themselves.

How Loud Are Current Synology Models?

Synology lists the DS725+ at just 17.9 dB(A) and the DS225+ at 19.6 dB(A). The DS925+ is rated at 20.5 dB(A), while the larger DS1525+ reaches 22.6 dB(A) and DS1825+ 23.8 dB(A). These numbers need context.

Synology conducts its noise tests with systems fully populated with specified drives, in an idle state, using microphones one meter from the front and rear. Real-world acoustics will depend on the drives, fan setting, workload, room, furniture, and placement. A NAS performing RAID operations or heavy random I/O can sound quite different from the same NAS sitting idle.

Quiet Mode Can Help, but Temperature Still Matters

Current DiskStation Plus systems provide multiple fan modes, including Full-Speed, Cool, and Quiet Mode.

Quiet Mode can be useful when the NAS is located close to users. But silence should not become more important than appropriate cooling. A larger NAS containing multiple HDDs generates heat continuously. Placing it inside a closed cabinet simply to hide the sound can restrict airflow and increase temperatures.

The better approach is usually to place the NAS somewhere with ventilation while physically separating it from noise-sensitive work areas. Sometimes moving a NAS several feet away provides more benefit than trying to make every fan run slower.

A NAS Is Also a Small Heater

Nearly all of the electricity consumed by computing equipment eventually becomes heat. Synology publishes thermal output figures that make the difference between models easier to visualize. The DS225+ is rated at approximately 57.9 BTU/hr during access. The DS925+ reaches about 129.3 BTU/hr.

The DS1525+ reaches approximately 152 BTU/hr, while the DS1825+ is rated at almost 205 BTU/hr during access. One NAS will not normally overwhelm a properly ventilated room, but several NAS devices, servers, switches, UPS systems, and other equipment can create a noticeable thermal load.

That can lead to an indirect ownership cost: air conditioning.

Don’t Buy Eight Bays When Four Will Do

A larger NAS can be a smart investment when you genuinely need future storage expansion. But buying substantially more bays than necessarily has consequences. More available bays often encourage more drives. More drives mean additional electricity, heat, vibration, replacement costs, and potential noise. Synology consulting can help size storage around long-term business needs.

On the other hand, buying a NAS that is too small can force you into an expansion unit or complete replacement sooner than expected. The goal should therefore be reasonable growth capacity, not simply buying the largest DiskStation within budget.

Larger Drives Can Sometimes Be More Efficient Than More Drives

Suppose you need a certain amount of usable storage. There may be a meaningful operational difference between achieving that capacity with several smaller HDDs and using fewer higher-capacity drives.

Fewer drives can potentially mean:

Lower power consumption
Less heat
Less vibration
Less acoustic noise
Fewer drives to replace
More unused bays for future expansion

RAID requirements, performance, capacity planning, rebuild risk, and drive pricing still need to be considered, so this is not simply a recommendation to buy the largest HDD available. But capacity per drive should be part of long-term NAS planning.

2.5GbE and 10GbE Can Change the Equation Too

Network upgrades have their own power and heat implications. A NAS equipped with faster networking may encourage heavier workloads, more simultaneous transfers, SSD caching, or additional storage activity.

For a business that needs the performance, those costs are easily justified. For a home NAS that primarily performs nightly backups, upgrading every component simply because the option exists may increase cost without producing a noticeable everyday benefit. Match networking to the workload just as carefully as storage capacity.

Calculate Five-Year Cost Before Choosing the NAS

When Epis Technology evaluates a Synology deployment, the useful question is not simply:

“Which Synology can we afford today?”

A better question is:

“Which Synology provides the capacity and performance we need over the next several years without unnecessary operating costs?”

That analysis should include:

NAS + drives + memory + networking + electricity + cooling + future expansion + replacement drives

A DS1825+ may be the right choice for a business expecting substantial storage growth. Its higher electricity consumption is insignificant if it prevents an expensive infrastructure replacement two years later. A Synology performance review can help match hardware to workloads.

But an eight-bay system may be unnecessary for a small office that expects to remain below the practical capacity of a four-bay DS925+.

The Cheapest Synology to Buy Isn’t Always the Cheapest to Own

Power consumption alone should not determine which Synology NAS you purchase.

Even running continuously, current desktop DiskStation models can have relatively modest direct electricity costs compared with many full-sized servers. The larger ownership differences often emerge from the number of drives, storage configuration, cooling requirements, networking, and future expansion decisions.

Noise matters too, particularly when the NAS will operate in a home office or shared workspace rather than a dedicated server room. The best strategy is to size the system around usable capacity, growth, workload, physical location, and expected service life.

A correctly sized Synology can operate quietly and efficiently for years. An oversized system wastes resources, while an undersized NAS can force an expensive upgrade long before the hardware itself needs replacing.

About Epis Technology

Epis Technology helps businesses choose and deploy Synology infrastructure based on long-term capacity, performance, reliability, and operating requirements rather than specifications alone. Services include Synology model selection, storage sizing, HDD and SSD planning, memory upgrades, 2.5GbE and 10GbE networking, NAS migrations, DSM configuration, enterprise backup, Microsoft 365 and Google Workspace protection, ransomware resilience, and disaster recovery. Epis Technology can help calculate whether a smaller DiskStation, expandable Plus model, or larger business NAS provides the best long-term value while accounting for capacity growth, power, heat, noise, and future infrastructure requirements.