When the Heat Rises, So Does the Tension: Workers and the Heatwave Problem
Every summer, as temperatures climb and office fans whir at full speed, millions of workers across the UK find themselves sticky, exhausted, and quietly furious. Some describe the feeling as being "like cats on a hot tin roof" — restless, uncomfortable, and utterly unable to concentrate. Many are quietly downing tools early, slipping out before the end of the workday simply to escape the unbearable heat. But here is the uncomfortable truth that most people don't know: there is no legal maximum temperature for a workplace in the UK. None. Not a single degree on the thermometer that, once crossed, gives a worker the automatic right to go home.
That legal gap might surprise you, and it is causing real friction between employees and employers every time a heatwave rolls in. So what does the law actually say? What responsibilities do employers carry? And what practical steps can workers take to protect themselves when the mercury refuses to drop?
The Legal Landscape: A Surprising Gap in Worker Protections
When it comes to cold workplaces, UK law is relatively clear. The Workplace (Health, Safety and Welfare) Regulations 1992 state that indoor workplaces must maintain a "reasonable" temperature — and guidance suggests that means at least 16°C for most work, or 13°C for physically demanding roles. But look for the equivalent upper limit and you will find nothing. No ceiling temperature. No mandatory send-home threshold.
The Health and Safety Executive (HSE) has long been asked to set a maximum, and it has consistently declined. The argument is that what constitutes an unsafe temperature varies enormously depending on the type of work, the physical demands of the job, and the individual worker. A baker working next to an industrial oven operates in a very different environment from a call centre employee sitting at a desk, so applying a single number to both situations would be impractical at best and counterproductive at worst.
Instead, the law leans on a broader duty of care. Under the Health and Safety at Work Act 1974, employers are legally required to ensure, so far as is reasonably practicable, the health, safety, and welfare of their employees. That broad obligation absolutely encompasses thermal comfort — but it leaves a great deal of room for interpretation, and it is precisely that grey area that causes so much conflict during a heatwave.
What Employers Are Actually Required to Do
Even without a legal maximum temperature, employers are far from off the hook when a heatwave strikes. Their duty of care means they must carry out a risk assessment that accounts for heat, and then act on the findings. In practice, this means a range of reasonable measures should be in place before workers start suffering.
- Provide fans and ventilation: Portable fans, improved airflow, and where possible air conditioning units are among the most effective and cost-accessible responses to workplace heat.
- Allow flexible working hours: Letting employees start earlier or finish later to avoid the hottest part of the day is a straightforward adjustment that many businesses can make without significant disruption.
- Relax dress codes: Insisting on formal business attire during a heatwave when no clients are present is both unnecessary and potentially harmful. Employers should permit cooler, casual clothing where practical.
- Provide access to cold drinking water: This is not optional. Employers must ensure workers have access to clean, fresh, and ideally cold water throughout the working day.
- Introduce rest breaks: Additional or extended breaks in cooler areas of the building help workers recover from sustained heat exposure and reduce the risk of heat exhaustion.
- Identify and protect vulnerable workers: Pregnant employees, older workers, those on certain medications, and individuals with underlying health conditions are at significantly greater risk in high temperatures and should receive additional support and monitoring.
Employers who ignore these obligations and allow workers to become ill as a result of heat exposure can face enforcement action from the HSE, and potentially civil claims from affected employees.
Workers Downing Tools: Is It Ever Legal to Refuse Work Due to Heat?
The sight of workers heading for the door early during a heatwave is increasingly common, and it raises an important legal question. Can an employee legally refuse to work if they believe the temperature poses a risk to their health?
Under Section 44 of the Employment Rights Act 1996, workers have the right to leave or refuse to return to a workplace if they reasonably believe there is serious and imminent danger that they could not reasonably be expected to avert. This is a relatively high bar to clear — courts have not typically ruled that everyday summer heat meets that standard — but in extreme circumstances, particularly where a vulnerable worker has raised concerns that an employer has ignored, the protection could apply.
What is far more important is the process. Workers should raise concerns formally with their employer or line manager before walking out. If internal channels fail, contacting the HSE or a trade union representative is the appropriate next step. Unilaterally leaving the workplace without following proper procedures risks disciplinary action, even if the underlying concern about heat is entirely justified.
Outdoor Workers: A Heightened Risk Often Overlooked
Much of the conversation about workplace heat focuses on offices and indoor environments, but outdoor workers — construction workers, agricultural labourers, delivery drivers, road crews, and many others — face acute risks that can escalate far more rapidly. These workers are exposed to direct sunlight, have fewer opportunities to access shade or cool spaces, and often perform physically intensive tasks that raise their core body temperature independently of the ambient heat.
For outdoor workers, the risks of heat exhaustion and potentially fatal heatstroke are very real. Employers overseeing outdoor teams must schedule the heaviest work during the cooler parts of the day, provide shaded rest areas, mandate regular hydration breaks, and actively monitor workers for early signs of heat-related illness such as dizziness, nausea, heavy sweating, and confusion.
How to Recognise Heat Exhaustion and Heat Stroke
Understanding the warning signs of heat-related illness is essential for both employers and workers. Heat exhaustion typically presents with heavy sweating, pale and clammy skin, a fast or weak pulse, nausea, muscle cramps, tiredness, and dizziness. A person experiencing heat exhaustion should be moved to a cool environment immediately, given water to drink, and helped to cool down with damp cloths or a cool shower.
Heatstroke is a medical emergency. The key distinction is a high body temperature above 39°C combined with confusion, slurred speech, loss of consciousness, or an absence of sweating despite the heat. Anyone showing signs of heatstroke requires an immediate call to emergency services. This is not a situation to manage internally — it can become life-threatening within minutes.
Calling for Change: The Campaign for a Legal Maximum
Trade unions, including the Trades Union Congress (TUC), have campaigned for many years for the introduction of a legal maximum workplace temperature — a figure often cited at 27°C for most roles, with 24°C proposed for physically demanding work. Advocates argue that a clear legal limit would remove ambiguity, hold employers accountable, and protect workers who currently have no bright-line threshold to point to when raising complaints.
Opponents of a fixed limit maintain that the flexibility of the current framework is its strength, allowing the law to adapt to different industries and contexts. The debate continues, and with summer temperatures in the UK trending higher year on year due to climate change, it is unlikely to cool down anytime soon.
What Workers Should Do Right Now
If you are currently struggling in an overheated workplace, the most effective steps are practical and procedural. Raise your concern in writing with your employer or HR department, referencing their duty of care under health and safety legislation. Keep a record of temperatures in your workspace. If your employer fails to act, contact your trade union if you are a member, or submit a complaint to the HSE. You can also speak to an employment solicitor about whether your specific situation warrants further action.
Heatwaves are becoming more frequent, more intense, and longer-lasting. Workers deserve to be protected from them — and while the law may not yet provide a clear numerical limit, it does provide real obligations that employers must meet. Knowing your rights, and your employer's duties, is the first step toward a safer, cooler workplace.