The UK’s July heatwave provided a timely warning for businesses that rely on server rooms, network cabinets and small communications cupboards. By 10 July 2026, the Met Office recorded an unprecedented run of days above 34 degrees. It reported eight days above 34°C during 2026, more than in any previous year, while temperatures of at least 35°C had been recorded in May, June and July for the first time in the UK weather record.
IT equipment generates heat continuously. If cooling fails or warm air cannot escape, servers, switches, firewalls and storage devices may reduce performance, produce errors or shut down to protect themselves. Excessive heat is therefore a business continuity risk, not merely a workplace comfort issue.
What heat does to your equipment
Processors and other components are designed to operate within limits specified by their manufacturers. As inlet temperatures rise, internal fans usually work harder and processors may reduce their operating speed. Continued exposure outside the recommended range can shorten equipment life or cause a protective shutdown.
| Room or equipment-inlet temperature | What it means for your equipment |
|---|---|
| Below 18°C | Usually cooler than necessary. Check humidity and dew point rather than assuming that lower is always better. |
| 18°C to 27°C | The commonly used ASHRAE recommended inlet-temperature range for air-cooled IT equipment. |
| Above 27°C to 32°C | Outside the recommended range, although some equipment may remain within its allowable manufacturer limits. Investigate cooling and airflow. |
| Above 32°C | Increasing operational risk. Check the equipment specification and take prompt action to reduce the temperature. |
The 18°C to 27°C range applies to the air entering the equipment, not necessarily a reading taken elsewhere in the room. Humidity, airflow, equipment class and manufacturer limits also matter. A short temperature increase does not guarantee failure, but sustained heat reduces the margin available if cooling or ventilation deteriorates.
The cupboard everyone forgets
Purpose-built server rooms normally receive regular attention. Smaller cabinets are easier to overlook. A switch, firewall or compact server placed in a closed cupboard can create a local hotspot even when the wider office feels comfortable.
Install temperature monitoring close to the equipment’s air intake, rather than beside an open door or directly beneath an air-conditioning outlet. Alerts should be set early enough for someone to investigate before the manufacturer’s recommended range is exceeded.
The response procedure should identify who receives the alert, who can access the site and which equipment can be shut down safely. Adding these controls to your business continuity planning is more reliable than waiting for users to report an outage.
Office continuity is more than servers
High temperatures can also affect employees and building access. UK law does not set a maximum workplace temperature, but the Health and Safety Executive says employers must assess extreme heat as a workplace hazard and take reasonably practicable steps to control the risks.
Cloud services can help staff continue working when an office becomes unavailable, but only when devices, authentication, permissions and remote-working procedures have been prepared in advance. Effective Microsoft 365 support can make access to email, shared files and collaboration tools more dependable.
Heat is only one cause of disruption. A failed disk, power cut, burst pipe or ransomware attack can produce similar operational consequences. A tested cyber incident response plan, appropriate email security and routine neglected IT management activities such as patching, backups and recovery testing should form part of the same continuity programme.
A short heat checklist for London offices
Measure the temperature: Monitor every room, cabinet or cupboard containing important live equipment.
Check airflow: Keep vents clear, remove stored items from around equipment and avoid trapping hot exhaust air.
Service cooling: Inspect fixed or portable cooling before periods of extreme heat.
Configure alerts: Use thresholds based on the equipment’s location, inlet temperature and manufacturer guidance.
Plan the response: Decide who investigates, what can be shut down and how employees will work if the office becomes unavailable.
Book a review before the next hot spell
A heatwave exposes weak cooling, missing monitoring and unclear recovery procedures. A managed IT support in London team can review equipment locations, temperature alerts, cooling dependencies and fallback arrangements. Speak to Northern Star about strengthening your server-room monitoring and wider continuity plan before the next prolonged hot spell.
