Do data centres ‘hum’?
Data centres do produce noise, primarily from their cooling systems, but that noise is tightly regulated and actively mitigated through design, technology, and planning controls, making data centres comparable to other everyday industrial infrastructure.
What are data centres?
Data centres are specialised and secure facilities that house and operate IT infrastructure used to store, process, and distribute data. If a service uses the internet, it is almost certainly running a data centre somewhere. Together with communications networks, they form our digital infrastructure.
Data centres underpin all digital activity. This covers everyday uses, such as backing up photos on a phone, as well as complex tasks like processing large datasets for weather forecasting and scientific research.
There are several types of data centre:
Enterprise data centres are privately owned and run by a single organisation for its own IT needs, while colocation facilities (the dominant model in the UK and Europe) let an operator provide space, power and cooling to multiple customers who bring their own servers.
Hyperscale data centres are much bigger sites run by major tech firms like AWS, Microsoft and Google to power cloud and global digital services, alongside an emerging category of neocloud providers building GPU-based platforms specifically for AI training and inference.
Finally smaller edge data centres are sited close to end users to minimise latency – the time it takes for data to travel between a user and a data centre – for things like gaming or real-time systems.
Do data centres create noise?
Data centres can generate noise, however, where that noise comes from, how often it occurs, and how it is managed depends on how a facility is designed, how it operates, and where it is located. Typically, in the UK, noise is more rigorously controlled than in other regions, particularly the United States, due to stricter planning and environmental requirements (see below).
What causes noise in data centres?
1: Cooling systems
The main sources of noise in a data centre are its cooling systems, which typically account for around 75% of a data centre's overall noise, because large volumes of air need to be moved continuously to manage heat.
Cooling is needed because servers (the high-powered computers that contain electronic chips that run applications, store and process data, and handle network requests) generate significant amounts of heat when operating continuously. This is similar to how a laptop can heat up when it has many applications running at the same time. The chips are also often designed to specialise within certain environments and under specific conditions. A cutting-edge smartphone chip, for example, requires different temperature tolerances to those used in electric vehicles or space satellites.
For use in data centres, specialised chips therefore require continuous heat management to prevent damage and maintain performance. Temperature and humidity limits are agreed between data centre operators and their customers under strict service level agreements (SLAs).
Within cooling systems, the largest source of noise is fans on air-cooled chillers, dry coolers or cooling towers, which are usually external to the building, though sometimes mounted on the roof. Without noise suppression, these can be quite loud, and the noise itself is consistent, since the equipment runs constantly. Inside the building, fans circulating air through the server racks generate a much softer mechanical "hum" – the sound most often associated with data centres.
The second-largest source is the refrigerant compressor, which is mounted externally on an air-cooled chiller or enclosed within a container or the building for a water-cooled chiller, helping to contain the noise it produces.
While the noise footprint in decibels variers from site to site, the typical noise levels from the cooling system are around 70-100 dB at source, with mitigation measures generally aiming to bring this down to around 50 dB at the site boundary. For comparison, 80 bB is the general noise level in a factory.
2: Electrical equipment
Transformers, switchgear and other electrical equipment can produce noise. While generally quieter than cooling systems or generators, because the UK's electricity supply runs at 50Hz, transformers produce a hum at this single frequency through an effect called magnetostriction. Because it is a single, constant tone rather than mixed-frequency noise, it can be more noticeable and perceived as more annoying, even at similar volumes.
Typical noise levels are around 40-65 dB, rising to around 80 dB near substations; screening or housing transformers within buildings is commonly used to control this. Switchboards and uninterruptible power supply (UPS) units, by contrast, are located indoors and typically generate around 45-75 dB at close range, so they have little to no impact beyond the site boundary.
3: Backup generators
Another source of noise is backup power generation. Given data centres are recognised as Critical National Infrastructure (CNI) and most sign strict Service Level Agreements with customers that require 99.999% power availability, back-up generators (gas- or diesel-fired or Hydrotreated Vegetable Oil) are a necessary resilience requirement.
However, UK data centres are classed as ultra-low use, since generators are used for standby during emergencies or for routine testing, rather than primary power and are tightly regulated by the Environment Agency (EA). This means their use must not exceed 50 hours within a rolling 12-month period, although exemptions can be sought if, for example, there is a prolonged grid outage.
When operating, they produce a constant rumbling noise, with a brief change on start-up before settling; typical noise levels are around 70-90 dB at source, and this is managed through measures such as enclosures, fitted with exhaust silencers and attenuators. These measures significantly reduce the noise that reaches nearby communities.
4: On‑site generation
In some countries, particularly the United States, some data centres operate on-site gas turbines to provide continuous primary power. These turbines run 24 hours a day and can create constant low‑frequency noise. UK data centre generators are typically standby generators, used only if mains power fails; onsite continuous power (gas) generation is largely absent in the UK due to permitting and other regulations governing the production of power.
5: Construction activity
Noise is also generated during the construction of data centres. This includes vehicle movements, heavy machinery, and installation work. While temporary, construction noise can be disruptive if not properly managed.
How is noise regulated?
Noise from data centres in England is controlled through a combination of planning policy, environmental permitting and wider legislation. There are no fixed noise limits, instead, impacts are assessed and managed on a site-specific basis.
At a national level, the National Planning Policy Framework (NPPF) sets out the Government’s approach to land use. It requires that development avoids significant adverse impacts on health and quality of life, mitigates noise where it cannot be avoided, and protects areas valued for tranquillity. This is supported by Planning Practice Guidance (PPG) on Noise, which helps decision-makers assess potential impacts.
Wider legislation includes The Environmental Noise Regulations 2006 which requires any major noise sources (such as roads, railways, airports, large urban areas, and some industrial activity) to produce strategic noise maps and action plans. In practice, developers must carry out Noise Impact Assessments (NIAs) to support planning applications, and where required, their Environmental Permits. NIAs typically measure existing background noise levels at nearby receptors and predict how the proposed development will affect them.
Assessments are often undertaken in accordance with recognised standards such as BS 4142, which compares operational noise against existing background levels. Low-frequency noise is also considered where there is potential it could create an impact. Where risks are identified, mitigation measures such as acoustic enclosures, barriers or layout changes (as explored below) may be secured through planning conditions or Environmental Permits. Environmental Permits may also require the submission of a Noise Management Plan.
The Environment Agency (EA) oversees noise related to permitted activities such as backup generation, while local authorities determine planning applications and investigate complaints, under The Environmental Protection Act 1990. Moreover, the Control of Noise at Work Regulations 2005 apply within data centres to protect employees from high noise levels, particularly if working in areas such as data halls.
How operators manage and reduce noise
Data centres consider how noise can be mitigated from the earliest stages of planning, including housing generators in enclosures fitted with attenuators, and equipping cooling plant with variable-speed fans, inverter-driven fans and acoustic louvres. These measures are explored in detail below. In the planning phase, operators typically use acoustic modelling to determine the optimal placement of buildings and equipment.
By positioning plant and buildings as far as possible from sensitive receptors within the constraints of the site, and by building screens around rooftop plant areas to block direct line of sight, operators can help shield nearby areas from noise.
In terms of equipment choice, fan noise specifically can be reduced in several ways: fitting attenuators (similar to a car muffler) which affects fan efficiency but also adds to power demand; using more or larger fans that spin more slowly, since noise increases with fan speed, though this brings additional capital and space costs; using variable-speed or inverter-driven fans, which run more slowly during periods of lower demand; and using adiabatic sprays, where the evaporation of water reduces the heat load so fans can move less air overall and run more slowly. Acoustic louvres are also fitted around cooling plant to allow airflow while reducing the noise that escapes.
Compressor noise is reduced in a similar way: water-cooled chillers housed within a container benefit from the container walls containing the sound, while air-cooled chiller compressors can be surrounded by a sound-insulated enclosure, though this adds cost and is generally less effective than a water-cooled chiller in a container.
Water is general is more efficient at transferring heat than air more broadly, requiring less energy and reducing fan use. However, it can require higher water consumption, raising challenges in water-stressed regions. In the UK, many data centres that do rely on water for cooling use closed-loop systems, where the same water is continuously recirculated within a sealed circuit, minimising both resource use and noise.
Improvements higher up in the supply chain, in hardware, system design and chip optimisation, are also allowing facilities to run at higher temperatures, reducing the need for intensive cooling. Some facilities use liquid-based or refrigerant-based cooling systems, which can be quieter than traditional air cooling:
Liquid cooling involves circulating water or specialised coolant directly to server components or through heat exchangers. Because liquids transfer heat more efficiently than air, systems can operate with fewer or slower fans, reducing noise.
Refrigerant-based systems (such as direct expansion cooling) use phase-changing fluids to absorb and remove heat, often within sealed systems that minimise mechanical noise.
Battery storage systems (BESS) can also help by reducing how often backup generators need to be tested, thereby lowering intermittent noise. In addition, modular and prefabricated construction methods shorten build times and help limit construction-related noise. How noisy are data centres compared with other activities?
Typical sound levels used in UK assessments include:
30 dB(A): rural area at night
40 dB(A): public library
50 dB(A): quiet office
60 dB(A): normal conversation
70 dB(A): boiling kettle at 0.5 metres
80 dB(A): general factory noise
90 dB(A): heavy goods vehicle close to pavement
100 dB(A): powered lawnmower or large industrial equipment
The actual impact of a data centre depends on distance, building design, surrounding land use, and existing background noise levels. Low-frequency sound is particularly important because it travels further and is less easily reduced by barriers or measured by standard metrics.
Conclusion
Data centres can produce noise, but they are not inherently noisier than other forms of industrial infrastructure. This should be recognised in light of the fact that the UK tech sector contributes £101 billion in Gross Value Added (GVA), and outpaced national growth at a rate of 8.9% in 2025. This will only increase as we accelerate artificial intelligence (AI) adoption in sectors like autonomous vehicles, agricultural technologies and climate-modelling. All of this growth and transformation relies on data centres and as such should be viewed as the roads and factories of the digital age.
It should also be noted that in the UK, the noise impacts of data centres are actively assessed and regulated. Most operational noise comes from cooling equipment and backup generators, both of which are subject to stringent planning and environmental oversight as discussed above.
As demand grows, the sector continues to invest in quieter cooling technologies, improved acoustic design and better integration with surrounding communities. In practice, UK data centres operate within a very different regulatory and operational landscape from high profile international examples, and noise is increasingly treated as a design challenge rather than an unavoidable consequence of digital infrastructure.
