Is Maximum Workplace Temperature Legislation Possible?

By Ben Read
28 Jul 2022

Following the Great British Heat Wave, many employees (and employers) across the country are asking the question:

"Why isn’t there a legally enforceable maximum workplace temperature?"

This isn’t the first time questions about the maximum temperature in the workplace have come up. However, it is the first time it has become a real possibility in the UK.

Why haven’t we already got a maximum workplace temperature?

Is there a maximum temperature in the workplace already?

Currently, there is no legal maximum indoor workplace temperature in the UK. You do have a legal obligation to provide a ‘reasonable’ temperature to keep the workplace comfortable, which is between 21-26 degrees Celsius. However, this is dependent on the environment and not just temperature. You should take factors such as air movement, ventilation, and air conditioning into account.

In the HSE ACOP L24 Paragraph 61 for Welfare Regulations 1992 suggests the minimum indoor temperature should be at least 16ºC. This decreases to 13ºC for those doing physical work, or where there is a specific need for temperatures to be controlled. Examples of this include chilled/frozen food or foundry workers.

In these scenarios, suitable Personal Protective Equipment (PPE) should be worn. Again, all reasonable steps should be taken to achieve a temperature as close as possible to comfortable.

The reason for this is that in some workplaces, such as foundries or glass works, extreme temperatures are the norm. In the event that the HSE introduce a maximum temperature in workplaces, UK foundries and similar businesses could be forced to close. At the very least, they’d have to introduce measures that would severely impact productivity.

If you’re looking for an answer to the question:

“How hot is too hot to work?”

The answer is that there is no legal definition, so this will depend on the individual and their work circumstances. This may not always be the case, though…

So, will we ever get a maximum workplace temperature?

This year MPs are now considering implementing a workplace maximum temperature. They’ve suggested a limit of 30C as a legal maximum temperature in the workplace in the UK. 27C For anyone doing strenuous work, such as builders.

This is being seriously considered now that extreme temperature events in Europe are now 10 times more likely than they were a decade ago. The recent extreme heat alert in the UK warned that the temperature was likely to cause “population-wide adverse health effects,” such as “potential serious illness or danger to life.”

Extreme temperatures are a major cause of economic loss and an increase in heat waves also impacts existing health & safety risks. With temperatures set to rise, it is only so long before a legal maximum temperature is implemented. But how much worse can it get?

Met Office climate attribution scientist Nikos Christidis said in a press release:

“40°C days in the UK are now as much as 10 times more likely than they would be ‘under a natural climate unaffected by human influence.”

As these severe heat waves become more common, the chance of maximum temperature legislation coming into force increases. Although it might not be as soon as some of us may like.

What can we do in the meantime?

Employers are still legally responsible for the health, safety and well-being of their employees. Making staff work in a hot working environment not only puts them at risk of heat stress but is also detrimental to business.

Workers are proven to be less productive in uncomfortable temperatures and so productivity will decrease as a result. Listen to your employees. If you have multiple complaints regarding the office temperature being too hot, carry out a risk assessment and take measures to reduce the risk.

Conducting a risk assessment

When you conduct a risk assessment, it’s not quite as simple as answering the question: “Is it too hot to work?”

Instead, there are two broad categories to take into account:

  • Environmental factors
  • Personal factors

Here’s what you need to look out for under each category and how it will impact your workplace…

Environmental factors

Air temperature

The temperature of the workplace. You probably already know this one, but it’s still worth observing how it changes throughout the day.

Radiant temperature

The heat that radiates from a warm object, such as ovens, computers, or machinery. This has a great influence on air temperature and needs to be factored in when assessing your work environment.

Perhaps some or all of your work happens outside, resulting in staff asking: "When is it too hot to work outside?"

It may sound obvious, but you need to take into account the sun as a source of radiant heat.

Air velocity

This is the speed of air moving across the employee. It may help cool them down if the air is cooler than the environment. Offices may have still or stagnant, which leads to it feeling stuff. On the other hand, those undertaking physical activity will experience more physical air movement.

Take these factors into account during your assessment.


Often, people only consider what temperature is too hot to work in. However, humidity is equally important.

The higher the humidity, the more vapour in the air. The more vapour in the air, the less sweat evaporates. Sweat evaporating is the main method people naturally reduce their heat.

Measuring humidity as well as temperature is a good way of making sure you get a more accurate representation of your employees’ environment. Relative humidity between 40-70% does not majorly impact thermal comfort.

Personal factors

Clothing insulation

Wearing too much clothing, or heavy clothing, can result in heat stress. This is particularly dangerous when the environment is also hot. As an employer, you must provide PPE where it is necessary. But, where PPE isn’t required, you should consider factoring in dress codes as a part of your strategy to beat the heat.

Work rate/metabolic heat

Physical work means we produce more heat. A person’s physical characteristics should always be taken into account when considering thermal comfort. Even in a work environment when the temperature is stable, two workers with different physical traits can experience different levels of thermal comfort.

Actions you can take when it is too hot to work inside

  • Relax policies on dress code, unless the dress code is required for safety reasons
  • Offer flexible working during periods of prolonged extreme weather temperatures
  • Provide cold drinks and food to help regulate staff temperature when working in the heat
  • Move workstations so they aren’t in the hottest areas of the office

Taking action will demonstrate that you take your employees’ well-being seriously, whilst maintaining morale and productivity. In the long term, you should plan ahead for future heat waves. Consider installing or upgrading air conditioning systems throughout the premises or creating smaller breakout rooms for staff to go to cool down.

For leased premises look at suitable alternative premises at renewal. Prioritise properties that already have provisions to cope with extreme temperatures.

Expert Support

For support on maximum workplace temperature law in the UK, or any other H&S issue, please contact a Croner expert on 0800 470 2816

About the Author

Image of Croner employee Ben Read

Experienced Senior Health, Safety, Environmental & Quality Assurance Manager with a demonstrated history of working within business solutions industry to motivate change and positive safety Cultures. Highly skilled Operations Management, facilitating teams to succeed and achieve their very best. Skill set includes but not limited to Environmental Issues, Workplace Safety, Occupational Health and Safety Management. I hold NEBOSH Diplomas in both Occupational H&S and Environmental Management. I also hold my Master of Science (MSc) focused in Occupational Health, Safety & Environmental Management from the University of Portsmouth.