Summary
- Slough hosts one of Europe’s largest data centre clusters, with dozens of facilities near the town centre.
- Emerging research links data centres to local heat island effects, although attribution remains complex.
- The debate connects cooling, waste heat, planning, public health, and the practical limits of heat reuse.
Slough’s concentration of data centres is facing sharper scrutiny as high temperatures push heat rejection, planning, and public acceptability further into the infrastructure debate.
The Berkshire town is one of Europe’s largest data centre hubs, with dozens of facilities serving cloud, enterprise, and connectivity customers. Its location west of London, close to fibre routes, electricity infrastructure, and the M4 corridor, has made it a long-standing anchor of the UK market.
The current pressure comes from two directions. Hotter summers are testing buildings, health services, transport, and local environments, while larger data centre loads are increasing the amount of electricity consumed and heat rejected by cooling systems.
A preprint study on the data heat island effect estimates that land surface temperatures increase by about 2C on average after AI data centres begin operating, with localised effects potentially affecting communities around facilities. The work is early and attribution in urban environments is difficult, but it adds a quantified frame to a debate that has often relied on anecdote.
Rejected heat leaves the fence line
Data centres convert almost all of their electricity into heat. Cooling systems remove that heat from servers and electrical equipment, then reject it through air, water, or hybrid systems. At facility level, that is a mechanical engineering function. At cluster level, especially in a dense town, it becomes an urban infrastructure issue.
Slough is exposed because data centres sit close to homes, roads, offices, and public services. Residents experience the physical presence of the sector through large buildings, roof plant, louvres, security perimeters, traffic, noise, and perceived heat. As more capacity is proposed around existing clusters, the cumulative effect becomes harder for planning authorities to treat one site at a time.
Heat attribution will remain contested. Roads, dark roofs, industrial buildings, air conditioning, traffic, and general urban form all contribute to local heat. A dense data centre cluster is one source among many, and separating individual effects requires careful measurement. The absence of simple attribution does not remove the need for better local evidence.
The debate also changes the way sustainability claims are heard. PUE, renewable energy procurement, and efficient cooling systems are important, but they do not answer every local question. Communities want to know what happens to heat, noise, water, air quality, grid demand, and the public realm around the buildings.
Heat reuse needs infrastructure, not slogans
Waste heat reuse is often presented as the answer. In principle, a data centre can supply low-grade heat to homes, public buildings, or commercial users through a heat network, often with heat pumps to raise temperature. In practice, heat reuse depends on nearby demand, pipe routes, investment, commercial offtake agreements, operating temperatures, and year-round load profiles.
Slough’s density gives the idea more weight than in remote campuses because there are potential heat users nearby. It also makes delivery more complicated. Retrofitting heat networks into built-up areas is expensive, disruptive, and dependent on long-term coordination between operators, local authorities, utilities, and customers.
AI demand sharpens the tension. Higher-density GPU deployments can increase power and cooling intensity, while the economic benefits of compute capacity may feel distant to nearby residents. Jobs, business rates, and supply-chain activity can help support the development case, but they do not neutralise concerns around heat and local amenity.
Planning policy will have to catch up with the cluster reality. A single data centre can be assessed through standard site-specific conditions; a concentration of facilities needs cumulative evidence on heat rejection, noise, grid stress, construction impact, and heat reuse potential. The same town cannot be assessed as if each facility operates in isolation.
Slough has already become a strategic data centre location. Its next phase will be defined by whether additional capacity can be reconciled with local heat, power, and planning constraints. The cooling system is no longer hidden behind the façade. It is part of the town’s infrastructure bargain.
