Heatwave: Temperature in the workplace

As an employer, it is important to know the risks of overheating, especially when working in hot conditions. With temperatures soaring in parts of Britain this week, it is time to make sure you have the right advice and guidance.

The following sections go over a number of common working scenario and include links to further guidance provided by HSE.

Office Environments

In offices or similar environments, the temperature in workplaces must be reasonable.
There’s no law for maximum working temperature, or when it’s too hot to work.
Employers must stick to health and safety at work law, including:

keeping the temperature at a comfortable level, sometimes known as thermal comfort

providing clean and fresh air

There are six basic factors which usually cause discomfort. Employees should talk to their employer if the workplace temperature isn’t comfortable.
Read about what you can do to feel more comfortable.



Indoor workplaces

You should provide:

a reasonable working temperature in workrooms – usually at least 16°C, or 13°C for strenuous work (unless other laws require lower temperatures)

local heating or cooling (ie making the best use of fans, opening windows, using radiators) where a comfortable temperature cannot be maintained throughout each workroom (eg hot and cold manufacturing processes)

thermal clothing and rest facilities where necessary, eg for ‘hot work’ or cold stores

heating systems which do not give off dangerous or offensive levels of fume into the workplace

sufficient space in the workroom



When people are too hot

You can help ensure thermal comfort in warm conditions by:

  • providing fans, eg desk, pedestal or ceiling-mounted fans
  • ensuring that windows can be opened
  • shading employees from direct sunlight with blinds or by using reflective film on windows to reduce the heating effects of the sun
  • siting workstations away from direct sunlight or other situations or objects that radiate heat (eg plant or machinery)
  • relaxing formal dress code – but you must ensure that personal protective equipment is provided and used if required
  • allowing sufficient breaks to enable employees to get cold drinks or cool down
  • providing additional facilities, eg cold water dispensers (water is preferable to caffeine or carbonated drinks)
  • introducing formal systems of work to limit exposure, eg flexible working patterns, job rotation, workstation rotation etc
  • placing insulating materials around hot plant and pipes
  • providing air-cooling or air-conditioning plant

Outdoor working

When working outdoors the effects of the weather in the UK environment can potentially have a serious impact on an employee’s health if the risks have not been considered or properly managed. This impact may be immediate or it may occur over a long time period.

When working outdoors hot weather can have an influence on an individual’s effectiveness and this is not readily managed using just engineering controls. In these circumstances some of the most effective ways of managing these environments are to introduce some simple administrative controls for example:

  • reschedule work to cooler times of the day
  • provide more frequent rest breaks and introduce shading to rest areas
  • provide free access to cool drinking water
  • introduce shading in areas where individuals are working
  • encourage the removal of personal protective equipment when resting to help encourage heat loss
  • educate workers about recognising the early symptoms of heat stress

Working in the sun

Too much sunlight is harmful to your skin. It can cause skin damage including sunburn, blistering and skin ageing and in the long term can lead to an increased risk of skin cancer. Skin cancer is one of the most common forms of cancer in the UK with over 50,000 new cases every year.
A tan is a sign that the skin has been damaged. The damage is caused by ultraviolet (UV) rays in sunlight.

 Find out more with the HSE guide ‘Keep your top on – Health risks from working in the sun‘.

Who is at risk?

If work keeps you outdoors for a long time your skin could be exposed to more sun than is healthy for you. You should take particular care if you have:

  • fair or freckled skin that doesn’t tan, or goes red or burns before it tans
  • red or fair hair and light coloured eyes
  • a large number of moles

What can you do to protect yourself?

People can manage their exposure to the sun by complying with guidance from HSE.

If your job involves extreme temperatures

In some workplaces, extreme temperatures are not seasonal but are created by the work, like in some manufacturing processes. These temperatures can lead to serious health effects if not managed effectively.

You should seek specific advice on temperature if you are working in very high or low temperatures, for example on heat stress, dehydration or cold stress.


Thermal comfort

The term ‘thermal comfort’ describes a person’s state of mind in terms of whether they feel too hot or too cold.

Environmental factors (such as humidity and sources of heat in the workplace) combine with personal factors (ie your clothing) and work-related factors (how physically demanding your work is) to influence your ‘thermal comfort’.

This website looks at what we mean by thermal comfort in the workplace and what the law says. It provides guidance for employers to help them manage their employees’ workplace thermal comfort.

What is thermal comfort?

Thermal comfort is very difficult to define as you need to take into account a range of environmental, work-related and personal factors when deciding what makes a comfortable workplace temperature.

The best that you can realistically hope to achieve is a thermal environment that satisfies the majority of people in the workplace. Thermal comfort is not measured by room temperature, but by the number of employees complaining of thermal discomfort. To better understand why room temperature alone is not a valid indicator of thermal comfort, see the six basic factors, a guide from HSE.

Why is thermal comfort important?

By managing thermal comfort you are likely to improve morale and productivity as well as improving health and safety. People working in uncomfortably hot and cold environments are more likely to behave unsafely because their ability to make decisions and/or perform manual tasks deteriorates. For example:

  • people may take short cuts to get out of cold environments
  • employees might not wear personal protective equipment properly in hot environments increasing the risks
  • an employee’s ability to concentrate on a given task may start to drop off, which increases the risk of errors occurring

As an employer, you should be aware of these risks and make sure the underlying reasons for these unsafe behaviours are understood and actively discouraged and/or prevented.

Adapting to the thermal environment

People adapt their behaviour to cope with their thermal environment, eg adding or removing clothing, unconscious changes in posture, choice of heating, moving to or away from cooling/heat sources etc.

The problems arise when this choice (to remove a jacket or move away from heat source) is removed, and people are no longer able to adapt. In some instances, the environment within which people work is a product of the processes of the job they are doing, so they are unable to adapt to their environment.

Measuring thermal comfort

A simple way of estimating the level of thermal comfort in your workplace is to ask your employees or their safety representatives (such as unions or employee associations) if they are satisfied with the thermal environment using the thermal comfort checklist.

Use the downloadable thermal comfort checklist (PDF) to help you identify whether there may be a risk of thermal discomfort to your employees.

Note: This is a basic checklist and does not replace a suitable and sufficient risk assessment, taking account of thermal comfort.

Read the descriptions for each thermal comfort factor, and tick the appropriate box. If you tick two or more ‘Yes’ boxes there may be a risk of thermal discomfort and you may need to carry out a more detailed risk assessment. 


Contact Us

Not sure where to start or you just need more information, feel free to contact us. You can send a message directly this link, or via email. Alternatively, you can call us on 01253 735 755.

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