When the Office Feels Like a Furnace: Heatwaves and the Modern Workplace
There is an old phrase about being "like a cat on a hot tin roof" — restless, uncomfortable, unable to settle. For millions of workers across the UK and beyond, that is exactly how summer heatwaves feel when they are stuck inside a sweltering office, a roasting warehouse, or a bakery-hot retail floor. As temperatures outside push into the high thirties, many employees are doing something about it: they are simply downing tools and going home early.
It sounds reasonable. It feels reasonable. But here is the uncomfortable legal truth — there is no official maximum temperature at which an employer is legally required to send workers home. While most people assume there must be some firm threshold written into law, the reality is far more ambiguous, and far less protective than workers might hope.
What the Law Actually Says About Workplace Temperature
In the UK, workplace temperature is governed primarily by the Workplace (Health, Safety and Welfare) Regulations 1992. These regulations state that employers must maintain a "reasonable" temperature in the workplace. For most indoor workplaces, this means a minimum of 16 degrees Celsius — or 13 degrees Celsius if the work involves significant physical effort.
Notice what is missing: a maximum. There is no upper legal limit. The Health and Safety Executive (HSE) has consistently resisted calls to set one, arguing that what constitutes an uncomfortable or dangerous temperature varies enormously depending on the type of work being done, the physical demands involved, the nature of the building, and individual differences between workers.
Instead, employers are guided by a general duty of care under the Health and Safety at Work Act 1974 to ensure, so far as is reasonably practicable, the health, safety, and welfare of their employees. When it comes to heat, this is interpreted broadly and loosely — which leaves a great deal of room for dispute.
Why Workers Are Walking Off the Job
The frustration felt by workers is entirely understandable. When indoor temperatures climb to 28, 30, or even 35 degrees Celsius, the physical and cognitive toll is significant. Studies consistently show that productivity drops sharply in high heat, concentration becomes harder to sustain, and the risk of heat-related illness — including heat exhaustion and heatstroke — increases substantially.
For office workers, the experience of sitting in a poorly ventilated room with aging air conditioning or no cooling system at all can be deeply unpleasant and distracting. For those doing physical labour — construction workers, factory floor staff, delivery drivers, agricultural workers — the stakes are considerably higher. Heat stress in physically demanding roles can become a genuine medical emergency.
With no clear legal line to point to, many workers have taken matters into their own hands, negotiating early finishes, working from home on the hottest days, or simply walking out — sometimes with their employer's blessing, sometimes without it.
What Employers Are Expected to Do During a Heatwave
Even without a maximum temperature law, employers are not entirely off the hook. The HSE provides guidance on what reasonable steps employers should take when workplaces become uncomfortably hot. These include:
Providing adequate ventilation and air movement through fans, open windows, or air conditioning units where possible.
Allowing workers to take more frequent rest breaks in cooler areas, particularly those engaged in physical labour.
Offering cool drinking water freely and encouraging workers to stay hydrated throughout the day.
Relaxing dress codes to allow lighter, more breathable clothing during hot spells.
Rescheduling physically demanding work to cooler parts of the day, such as early morning or late afternoon.
Conducting risk assessments that account for temperature as a specific hazard, particularly for vulnerable workers including older employees, pregnant workers, and those with underlying health conditions.
These are recommendations rather than rigid requirements, but failing to follow any reasonable precautions during extreme heat could leave employers exposed to legal challenge if a worker suffers harm as a result.
The Case for a Legal Maximum Temperature
Trade unions have long argued that the absence of a legal upper limit is an unacceptable gap in worker protection. The TUC and many individual unions have repeatedly called on successive governments to introduce a maximum workplace temperature of 30 degrees Celsius for general work, and 27 degrees Celsius for those doing strenuous physical activity.
Supporters of a legal limit argue that it would give workers a clear, enforceable right to refuse to work in dangerous heat without fear of disciplinary action. It would also force employers to plan proactively for hot weather rather than reacting on an ad hoc basis when complaints become impossible to ignore.
Opponents, including some employer groups and the HSE itself, counter that a single fixed number cannot account for the huge variation in workplace types, individual tolerances, and the fact that some workplaces — such as bakeries, foundries, or commercial kitchens — operate at high temperatures as a normal part of their function.
Your Rights as a Worker in a Hot Workplace
If you are struggling with heat at work, knowing your rights is the first step. While you cannot legally demand to go home simply because you feel warm, you do have meaningful protections. You have the right to raise concerns about your working conditions without facing retaliation. If you genuinely believe your health is at risk, you have the right under Section 44 of the Employment Rights Act 1996 to leave or refuse to return to a workplace that you reasonably believe poses a serious and imminent danger.
Practically speaking, raising the issue with your line manager or HR department is always the sensible first move. Document your concerns in writing. If your employer dismisses serious heat-related health risks without taking any action, contacting your trade union representative or the HSE directly may be the appropriate next step.
Looking Ahead: Heat, Work, and Climate Change
As climate change drives more frequent and more intense heatwaves across the UK and Europe, the question of workplace heat is only going to grow in importance. What was once a seasonal inconvenience is becoming a recurring occupational health challenge that employers, lawmakers, and workers need to take far more seriously.
The workers feeling like cats on a hot tin roof today are a preview of a much larger problem tomorrow. The law, as it stands, has not kept pace with rising temperatures. Until it does, workers must stay informed, speak up early, and hold their employers to the standard of care they are legally and morally obliged to provide.