HSE to Review Workplace Heat Rules as Pressure for a Legal Limit Grows

For anyone reading This Week in Health and Safety over the last few months, we’ve covered the extreme temperatures in the UK in great detail this year. Every summer I’ve been asked the same question: is it ever legally too hot to work? The short answer is that the UK has no maximum working temperature written into law, and it never has. The Health and Safety Executive (HSE) is reviewing the Approved Code of Practice that sits behind the workplace temperature rules, and a public consultation is expected. There could be a huge change on the horizon. Here's what's actually happening, what it could mean, and what employers should be doing now rather than waiting for a number to appear.

Key Takeaways

• There is currently no legal maximum working temperature in the UK, only a duty to keep workplaces at a “reasonable” temperature.
• The HSE is reviewing the Approved Code of Practice (ACOP) for the Workplace (Health, Safety and Welfare) Regulations 1992 and is expected to consult on changes.
• Unions including the TUC and Unison want a legal maximum of 30°C for indoor work, or 27°C for strenuous work.
• Whatever the review decides, employers already have a legal duty to assess and manage heat as a workplace hazard.

What Does UK Law Actually Say About Workplace Temperature?

Less than most people assume. The Workplace (Health, Safety and Welfare) Regulations 1992 require that indoor workplaces are kept at a temperature that's “reasonable” during working hours. That's the whole legal test. There's no figure attached to it at the top end.

The Approved Code of Practice that supports those regulations does put a floor in place: normally at least 16°C, or 13°C where much of the work involves rigorous physical effort. But there's no equivalent ceiling. The HSE's long-standing position is that a single upper limit would be difficult to apply fairly, because in plenty of workplaces the heat comes from the job itself. A commercial bakery, a foundry or a glasswork will run hot regardless of what the weather is doing outside.

So when someone tells me their office “legally has to close at 30 degrees,” I have to gently correct them. It doesn't. What the law does require is that the employer assesses the risk and does something proportionate about it.

What Is the HSE Reviewing, and Why Now?

The government committed, in its Next Steps to Make Work Pay work, to modernising health and safety guidance for extreme temperatures. As part of that, the HSE is reviewing the ACOP for the 1992 Regulations to make sure it's fit for purpose for a modern workplace. Ministers have confirmed the HSE will consult on that review, with an opportunity to respond in due course.

Sir Stephen Timms, Minister for Social Security and Disability, set out the government's position in Parliament, confirming that the HSE currently provides guidance for employers to manage heat risk and is progressing the wider ACOP review. The review covers the code as a whole, but workplace temperature is squarely within its scope.

The timing isn't coincidental. The pressure has been building through successive hot summers, and the case for revisiting decades-old guidance gets harder to argue against each time the mercury climbs.

What Are the Unions and Campaigners Calling For?

This is where the numbers come in. The demands aren't new, but they've grown louder:

• The TUC and Unison want a legal maximum indoor working temperature of 30°C, dropping to 27°C for strenuous work.
• They also argue employers should be required to act once temperatures pass 24°C and workers feel uncomfortable.
• A separate parliamentary petition has called for a legally binding maximum of 25°C across all workplaces.

The Climate Change Committee has also weighed in, recommending in its 2026 assessment that the government set maximum temperature regulations for work, though notably it stopped short of naming a figure.

Is a Single Legal Maximum Actually the Right Answer?

Not everyone thinks so, and the disagreement is more interesting than a simple for-or-against.

The British Safety Council has argued that the 1992 Regulations should be updated to include explicit protections against excessive heat and cold, but that this is better done through statutory guidance setting practical trigger temperatures and proportionate controls, rather than relying on a single fixed maximum or minimum. In other words: give employers clear thresholds that prompt action, but don't pretend one number works for an office, a warehouse and a steelworks alike.

I have a lot of sympathy for that view. A hard 30°C cut-off is easy to understand and easy to enforce, which is its appeal. But it risks being both too blunt for the bakery and too generous for the person doing heavy manual work in full PPE. A trigger-based approach, where hitting a threshold obliges the employer to act rather than to down tools, tends to map better onto how heat risk actually behaves.

What Should Employers Do Right Now?

Here's the part that matters most, and it doesn't depend on the outcome of any consultation. Your duties already exist. Waiting for a maximum temperature to be announced is not a strategy.

• Treat heat as a hazard in your risk assessments, indoors and outdoors, the same way you'd treat any other.
• Put practical controls in place: ventilation and cooling, shade, chilled drinking water, and more frequent rest breaks.
• Adjust the working day where you can, so the most demanding tasks happen during cooler hours.
• Relax dress and uniform requirements to allow looser, cooler clothing where it's safe to do so.
• Talk to your workers. Thermal comfort isn't measured by a thermometer alone; it's measured by the people telling you they're struggling.

Do those things well and you're not just complying with today's law, you're already most of the way towards whatever the revised code asks of you.

Frequently Asked Questions

Is There a Legal Maximum Working Temperature in the UK?

No. UK law requires workplaces to be kept at a “reasonable” temperature but sets no maximum figure. Employers must assess the risk from heat and take proportionate steps to protect workers.

What Is the Minimum Legal Working Temperature?

There's no absolute legal minimum either, but the Approved Code of Practice says indoor temperatures should normally be at least 16°C, or 13°C where much of the work involves rigorous physical effort.

What Is the HSE Reviewing?

The HSE is reviewing the Approved Code of Practice (ACOP) for the Workplace (Health, Safety and Welfare) Regulations 1992, including the guidance on workplace temperature, to ensure it is fit for a modern workplace. A public consultation is expected.

What Temperature Do Unions Want as a Legal Limit?

The TUC and Unison have called for a legal maximum of 30°C for indoor work, or 27°C for strenuous work, alongside a duty on employers to act once temperatures exceed 24°C and workers feel uncomfortable.

What Should Employers Do About Heat Now?

Assess heat as a workplace hazard and put practical controls in place: ventilation, shade, drinking water, more frequent breaks, adjusted hours and relaxed dress codes. These duties apply regardless of the outcome of the HSE review.

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