Workplace temperature law in the UK: what employers must do
Updated 23 October 2026 · SEO Dons Editorial
What does the law say about workplace temperature?
One regulation sets the duty. Regulation 7 of the Workplace (Health, Safety and Welfare) Regulations 1992 says that during working hours the temperature in all workplaces inside buildings "shall be reasonable". It contains no figure, so "reasonable" is judged for each workplace. Its other paragraphs matter to anyone running heating or cooling plant:
| Paragraph | What it requires |
|---|---|
| 7(1) | A reasonable temperature during working hours inside buildings |
| 7(1A) | Adequate thermal insulation where necessary, and excessive effects of sunlight on temperature avoided. Added on 17 September 2002 |
| 7(2) | No method of heating or cooling that lets fumes, gas or vapour escape into the workplace at a level likely to be injurious or offensive |
| 7(3) | A sufficient number of thermometers for people at work to determine the temperature |
The regulations apply to every workplace except those listed, such as ships, and HSE notes they do not cover construction sites or workplaces below ground at a mine. Legislation.gov.uk marks them as applying in England, Wales and Scotland, so employers in Northern Ireland should check HSENI.
Is there a legal minimum or maximum temperature?
Neither is written into the regulation. HSE says its Approved Code of Practice suggests the minimum for working indoors should normally be at least 16°C, or 13°C if much of the work involves rigorous physical effort. Treat those figures as the code's guide to what is reasonable, with "normally" leaving room for the type of work.
At the other end HSE is direct: there is no maximum temperature for workplaces. In many indoor workplaces the heat comes from the work itself, as in bakeries or foundries, so no single upper limit could fit. That does not remove the duty, because HSE classes heat as a hazard that carries legal obligations like any other.
How do you decide what is reasonable?
By assessing the risk and acting on the result. Regulation 3 of the Management of Health and Safety at Work Regulations 1999 requires every employer to make a suitable and sufficient assessment of the risks to employees, and HSE says temperature is one of them, indoors or outdoors. Its wording for the decision is to assess the risk and act on any findings by putting controls in place, including temporary or seasonal ones, after consulting workers or their representatives.
HSE's workplace temperature checklist is a quick screen: two "yes" answers mean you should assess the risks, though it does not replace a full assessment. Air temperature alone is not a valid indicator of comfort, so HSE sets out six factors:
| Factor | What HSE says |
|---|---|
| Air temperature | Measured in degrees Celsius, but not enough on its own |
| Radiant temperature | Has a greater influence than air temperature on how hot a space feels |
| Air movement | Moving air in warm or humid conditions increases heat loss without any change in air temperature |
| Humidity | Less sweat evaporates when humidity is high, over 80% |
| Clothing and PPE | A comfortable temperature depends heavily on the insulating effect of clothing |
| Work rate | Physical activity creates more body heat |
The simplest check is to ask your workers or their safety representatives whether they are satisfied with the thermal environment.
What should an employer do when the weather turns hot?
Have the plan ready before the heat, and agree what triggers it. The Met Office says a UK heatwave threshold is met when a location records at least three consecutive days with daily maximum temperatures at or above a threshold that varies by county. In England, UKHSA's heat-health alerts add a second prompt: an amber alert means weather impacts are likely across the whole health service and non-health sectors may also begin to see them, and a red alert indicates significant risk to life even for the healthy population. They are public health tools, not workplace law, but a sensible cue to review the steps below.
- Check and listen. Read the thermometers required by regulation 7(3) and ask staff. HSE says an employer should reassess the risks and act when workers report uncomfortable temperatures.
- Keep heat out. HSE lists blinds or reflective film, workstations away from direct sun and heat sources, and insulation around hot plant and pipes.
- Move the air. HSE lists desk, pedestal or ceiling-mounted fans and windows that can be opened, and warns that fans may cause draught or noise problems.
- Change how work is done. HSE suggests flexible working patterns, job rotation to cooler parts of the building, more breaks and cold water, and relaxed dress codes with personal protective equipment still used where required.
- Protect people at higher risk. HSE says to obtain occupational health advice for workers who are pregnant, have an illness or disability, or take certain medication, and to complete an individual risk assessment once a worker tells you in writing that she is pregnant.
- Add cooling where those steps fall short. A portable unit can cover a temporary gap, and the portable air conditioning guide sets out where it works. HSE notes that evaporative coolers give only a moderate reduction in air temperature and add humidity, a trade-off the evaporative cooling comparison explains.
When does fixed air conditioning become the sensible investment?
When cheaper measures leave a recurring problem. HSE gives engineering controls first place among its controls for a hazard, and its engineering examples include fans and air conditioning. The law does not require it, so the test is practical: is the heat predictable, and have simpler steps failed?
| Situation | Usual response |
|---|---|
| Discomfort in a few hot weeks, with openable windows and room for shading | Shading, fans and working-pattern changes first |
| Heat produced by equipment or processes all year, which HSE says is not seasonal | Engineering controls, including fans or air conditioning; see whether air conditioning is worth it |
| People in uniform or PPE who cannot adapt, or rooms where windows cannot open | HSE says adequate ventilation or air conditioning, and windows that open easily, become important |
| Repeat complaints after the steps above | Assess a fixed system sized and zoned for the space |
HSE describes air conditioning as a range, from small units that lower the air temperature but do not control humidity or air movement to large units that can cope with extreme conditions. It adds that air distribution must be uniform, otherwise some workers feel cold while others feel hot, and that units should be operated as the manufacturer instructs. A fixed system also brings its own legal duties, listed in the air conditioning regulations checklist. For offices, the office air conditioning page covers zoning and design, and readers who want a system assessed can send an enquiry through the site's form.
What does the 16°C guidance mean for heating?
It is the other half of the same duty. HSE says employers should provide a reasonable working temperature in workrooms, usually at least 16°C or 13°C for strenuous work, with adequate workplace heating, such as portable heaters, so work areas are warm enough when occupied. Regulation 7(2) still applies: heating must not give off dangerous or offensive levels of fume.
Sources
- Workplace (Health, Safety and Welfare) Regulations 1992, regulation 7, legislation.gov.uk, checked 22 October 2026
- Workplace (Health, Safety and Welfare) Regulations 1992, regulation 3, legislation.gov.uk, checked 22 October 2026
- Management of Health and Safety at Work Regulations 1999, regulation 3, legislation.gov.uk, checked 22 October 2026
- Temperature in the workplace: what the law says, Health and Safety Executive, checked 22 October 2026
- Temperature in the workplace: is it too hot or cold to work?, Health and Safety Executive, checked 22 October 2026
- Temperature in the workplace: managing workplace temperatures, Health and Safety Executive, checked 22 October 2026
- Temperature in the workplace: how workers can keep temperatures comfortable, Health and Safety Executive, checked 22 October 2026
- Thermal comfort, Health and Safety Executive, checked 22 October 2026
- Workplace temperature checklist, Health and Safety Executive, checked 22 October 2026
- Temperature in the workplace: heat stress, Health and Safety Executive, checked 22 October 2026
- Workplace health, safety and welfare: L24 Approved Code of Practice and guidance, Health and Safety Executive, checked 22 October 2026
- What is a heatwave?, Met Office, checked 22 October 2026
- Heat-Health Alerting system, UK Health Security Agency (GOV.UK), published 19 December 2024, checked 22 October 2026
Common questions
Does the 16°C figure apply to every room?
HSE describes 16°C, or 13°C where much of the work involves rigorous physical effort, as the minimum its code suggests should normally be reached indoors. Regulation 7 itself says only that the temperature must be reasonable. Use the figure as a starting point and let the risk assessment decide where a different level is justified.
Do employers have to provide thermometers?
Yes. Regulation 7(3) requires a sufficient number of thermometers so that people at work can determine the temperature in any workplace inside a building. It sets no number, so enough means enough to cover the real work areas.
Are fans enough in a heatwave?
HSE lists fans among the measures employers can provide, and notes that large-diameter ceiling fans can be effective over a wide area. It also warns that fans may cause draught or noise problems. Fans move air rather than cool it, so combine them with shading, ventilation and changes to working patterns.
What extra steps apply to a pregnant worker?
HSE says employers should obtain medical advice from an occupational health professional for workers who are pregnant. Once a worker informs you in writing that she is pregnant, you must complete an individual risk assessment and make any necessary changes to support her.
Does the 1992 regulation apply in Northern Ireland?
Legislation.gov.uk marks the Workplace (Health, Safety and Welfare) Regulations 1992 as applying in England, Wales and Scotland. Employers in Northern Ireland should check HSENI for the rules that apply there.
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