Managing heat in the workplace

During unprecedented heat waves over the summer, parts of the UK set new record temperatures. Kevin Clancy, Partner in our Workplace, Risk and Regulation team, discusses the legal implications of this upon UK employers.

19 June 2023

Temperatures in the UK have climbed to more than 30 degrees on a number of days during the first half of June.  That follows on from a record temperature of over 40 degrees having been set in the summer of 2022.  

UK temperature records from the Met Office show that, since 1884, all of the UK’s ten warmest years have occurred in the last two decades. So managing the heat is likely to be an issue for employers for many summers to come. 


The Health and Safety at Work Act 1974 requires employers to ensure the health, safety and welfare of their staff and others present in the workplace. But there is presently no set minimum or maximum temperature for indoor workplaces.  

Regulation 7 of The Workplace (Health, Safety and Welfare) Regulations 1992 (the 1992 Regulations) stipulates that the temperature in all workplaces inside buildings shall be ‘reasonable’.  

Of course, employers should also remember their overriding legal obligation to undertake a suitable assessment of health and safety risks to employees, of which temperature in the workplace would be one of many potential hazards to be considered, and thereafter put appropriate controls in place.

A sufficient number of thermometers should be provided to enable persons at work to determine the temperature in any workplace inside a building. Temperature readings should be taken close to workstations, at working height and away from windows.

While there are no stipulated temperature limits, the Health & Safety Executive (HSE) has an Approved Code of Practice (ACOP) with guidance for employers. The purpose of the ACOP is to help employers understand the regulatory requirements in the 1992 Regulations.  The ACOP was first published in 1992 and last updated in 2013. 

At the lower end of the scale, the ACOP notes that the temperature in a workplace such as an office should normally be at least 16 degrees Celsius. If work involves rigorous physical effort, the minimum temperature should be 13 degrees Celsius.

There is no maximum temperature recommended in the guidance, but there may be increased calls to introduce this in years ahead given the recurring hot summers. In July 2022 the GMB Union publicly called on the UK Government to set a maximum temperature of 25 degrees Celsius. NASUWT, the Teachers’ Union, has called on maximum classroom temperatures of 24 degrees Celsius to be set.


The ACOP notes that if a reasonably comfortable temperature cannot be achieved through local cooling systems in the building then, in extremely hot weather, fans and increased ventilation may be used.  The use of window blinds, or even keeping windows open to allow air to circulate, may even be effective.

When the ACOP was last updated in 2013, working from home was not particularly common. Employers may want to support staff with home working during periods of extreme heat. Alternatively, employers may consider relaxing formal dress codes during periods of extreme heat, or staggering shift patterns so employees can avoid travel between the hotter hours of the day.

Care should be taken as regards PPE, which could cause heat stress – mitigating controls (such as allowing longer recovery times or scheduling work for cooler times of the day) should be considered.  Employers should take particular care when dealing with employees who find working in the heat more difficult than others because of a disability, and should consider what temporary reasonable adjustments may be appropriate in these circumstances. Employees who are pregnant are also more susceptible to heat exhaustion, so employers should be prepared to take additional measures as necessary in special cases.

If you require any advice or guidance on managing employees in the extreme heat, please do not hesitate to contact Kevin Clancy or Neil Maclean in the firm’s Workplace, Risk and Regulation Group.