When is it too hot to work? What temperature does it have to be for you to leave work - UK laws explained

Temperatures will continue soar in the UK in the coming days as the Met Office has now issued amber heat alerts for this weekend's high temperatures. Forecasters have predicted that parts of the country could experience highs of 30C for the first time this year.

The heatwave is expected to continue over the weekend, however, yellow warnings for thunderstorms has also been put in place, with “heavy rain and hail likely to develop” on Saturday (10 June). Some workers will be in an office, while others will be outdoors, and others will be working from home.

So, can temperatures climb so high that it can become too hot to work, if so what temperature does it have to be before you can go home, and are the recommendations the same regardless of the setting of your workplace? Here’s what you need to know.

What does the law say?

Employers have a legal obligation to ensure that the temperature in the workplace is “reasonable”, as outlined by the Workplace (Health, Safety and Welfare) Regulations 1992. In addition, it is also the duty of employers to ensure that the air in the office is clean and fresh for their staff.

How hot does it have to be before you can leave your workplace?

The government hasn’t specified a maximum temperature that the workplace has to reach before you can be sent home. Efforts have, however, been made in the past to put one into place. In 2022, the Trades Union Congress (TUC) released a briefing that highlighted the temperatures that it believes should be maintained in various workplaces for the health and safety of workers.

It said that it believes a maximum temperature of 30C should be set by employers, but that it should be reduced to a maximum of 27C for those doing strenuous work. The TUC added that employers should still aim to keep temperatures below 24C and take note if employees say they are uncomfortable because of the temperature.

The Chartered Institute of Building Services Engineers also recommends different working temperatures for those doing different jobs. They recommend a working temperature of 13C for those undertaking heavy work in factories; 16C for those doing light work in factories; 18C for those working in hospital wards and shops; and 20C for those working in offices and dining rooms.

The government has, however, stated its recommended minimum temperatures for employees in workplaces. The Health and Safety Executive (HSE) recommends a minimum temperature of 16C for workers and 13C for those carrying out manual work under its Approved Code of Practice.

What can you do if you think your workplace has become too hot to work in?

A maximum temperature in the workplace may not have been legalised in the UK, but there are still some things you can do if you believe your workplace has become too hot for you to work comfortably. It is ultimately up to the employer to decide whether the temperature in the workplace is not suitable for work.

What should employers do to make sure their workplace is safe to work in?

The government recommends that employees speak to their bosses if they feel they can no longer work due to the heat. According to the Advisory, Conciliation and Arbitration Service (ACAS), employers should carry out a risk assessment for the health and safety of their workers in order to determine whether the workplace is a safe environment in which to work.

The HSE states that employers must take six factors into account when assessing whether their workplace is safe to work in. They are air temperature, radiant temperature, air velocity, humidity, what clothing they wear and the average rate at which they work.

The HSE has also created a thermal comfort checklist, which it recommends employers ask employees to fill out in order to determine if they’re experiencing discomfort relating to high temperatures. If people are working outdoors, it’s the employer’s responsibility to introduce rest breaks for them and encourage them to hydrate regularly.

If people usually wear business clothes to work, then it is advised that employers allow them to adopt a casual dress code for their comfort during hot weather.

What are the recommendations if you’re working from home?

By law, employers are responsible for the health and safety of all employees, including those working from home, according to the HSE, although the rules aren’t straightforward now that so many people work remotely. If you work from home your employer should still check that you feel the work you’re being asked to do at home can be done safely in a variety of circumstances.

If changes are needed, employers are responsible for making sure they happen, according to ACAS. Employees are responsible for telling their manager about any concerns they have and if they believe any homeworking arrangements they have need to change.

Homeworkers may also be able to buy equipment such as a fan through their company expenses system in some circumstances, if the temperature regularly exceeds what is reasonable.