Too Hot to Work? What UK Law Says About Workplace Heat

The Legal Position, Stated Plainly

The belief that work must stop at a particular temperature is one of the most durable myths in British employment. No such threshold exists. Regulation 7 of the Workplace (Health, Safety and Welfare) Regulations 1992 requires that during working hours the temperature in all workplaces inside buildings shall be reasonable, and that is the entire statutory test at the top end. The Approved Code of Practice supporting those regulations does put a floor in place, normally at least 16 degrees Celsius, falling to 13 degrees where much of the work involves rigorous physical effort, but it attaches no equivalent ceiling. The Health and Safety Executive has explained the asymmetry on the basis that no meaningful upper limit can apply across all sectors, because in workplaces such as bakeries, foundries and commercial kitchens high temperatures are generated by the work itself rather than by the weather.

What replaces a number is a duty. Under the Health and Safety at Work etc Act 1974 and the Management of Health and Safety at Work Regulations 1999, an employer must assess risks to health and safety and put proportionate controls in place, and heat is a hazard like any other. The Health and Safety Executive frames this through thermal comfort, which depends on air temperature, radiant heat, humidity, air movement, clothing and the physical effort of the task rather than on a thermometer reading alone. An office at 28 degrees with no air movement and a strict dress code may present a greater risk than a warehouse at 30 degrees with ventilation and free movement. The absence of a legal ceiling therefore does not mean the absence of an obligation.

What an Employer Has to Do

The practical obligations follow from the risk assessment rather than from a temperature. Where heat presents a risk, controls are expected to work through the same hierarchy applied to any hazard: remove the source where possible, then reduce exposure, then adapt working practices, and only then rely on personal measures. In an indoor setting that means addressing solar gain through blinds and window film, using ventilation and mechanical cooling where practicable, relocating heat-generating equipment, and relaxing dress codes that trap heat. In working patterns it means adjusting hours to avoid the hottest part of the day, rotating staff out of the hottest areas, introducing additional breaks and ensuring drinking water is readily available. Outdoor work carries its own controls: shade, scheduling, sun protection and monitoring for early signs of heat illness.

Certain groups warrant specific consideration in the assessment. Pregnant workers are entitled to a suitable and sufficient risk assessment covering their circumstances, and employers must alter conditions or hours where a risk cannot otherwise be avoided. Older workers, those with cardiovascular or respiratory conditions, those taking medication that affects thermoregulation and workers wearing protective equipment that restricts heat loss all carry elevated risk. Disabled employees may be entitled to reasonable adjustments under the Equality Act 2010, which can include changes to location, hours or equipment. These are individual entitlements that operate irrespective of the ambient temperature and irrespective of whether a general threshold is ever legislated.

What a Worker Can Do

The first route is procedural rather than legal. Concerns are raised with the employer or with a health and safety representative, and where a union is recognised its representatives have statutory functions including inspection and consultation. Where an employer does not act, a complaint can be made to the Health and Safety Executive or to the local authority, depending on which regulates the sector, and complaints may be made anonymously. The Health and Safety Executive has published advice for employers on managing heat in the current conditions, which workers can use as the reference point in that conversation rather than arguing from a temperature figure that does not exist in law.

The right to leave a workplace is narrower than commonly assumed. Sections 44 and 100 of the Employment Rights Act 1996 protect an employee from detriment or dismissal for leaving or refusing to return to a workplace in circumstances of danger the employee reasonably believed to be serious and imminent. Discomfort does not meet that test. Conditions producing symptoms of heat exhaustion in a vulnerable worker may do. The threshold is deliberately high, and the protection is retrospective, in that it is tested at a tribunal after the event rather than granting permission in advance. For most people the more effective lever remains the risk assessment, because an employer who has not carried one out where heat is an evident hazard is already in breach.

The Review Now Under Way

The position may not hold indefinitely. The Trades Union Congress and Unison have both called for a legal maximum indoor working temperature of 30 degrees Celsius, dropping to 27 degrees for strenuous work, together with a requirement on employers to act once temperatures pass 24 degrees and workers report discomfort. A parliamentary petition seeking a binding maximum of 25 degrees across all workplaces has gathered signatures through the summer. In its report published in May 2026, the Climate Change Committee recommended that government set maximum temperature regulations for work, in order to address the risks that high temperatures pose to workers and to encourage the deployment of cooling, though it did not itself propose a figure.

The government's response, given in Parliament during June and July 2026, was that the Health and Safety Executive is reviewing the Approved Code of Practice for the Workplace Regulations 1992, including the provisions on temperature, to ensure it remains fit for a modern workplace, and that the regulator will consult publicly. The British Safety Council has argued that the regulations should address excessive heat explicitly but that statutory guidance setting practical trigger temperatures and proportionate controls would work better than a single fixed maximum. The likely outcome, on the evidence so far, is clearer guidance and trigger points rather than a hard legal ceiling, since the objection that defeated earlier proposals, namely the bakery and foundry problem, has not gone away.

Frequently asked questions

Is there a maximum workplace temperature in the UK?

No. The Workplace (Health, Safety and Welfare) Regulations 1992 require only that indoor temperature is reasonable during working hours. The Health and Safety Executive has said no meaningful upper limit can apply across all sectors because some workplaces generate heat through the work itself.

What is the minimum workplace temperature?

The Approved Code of Practice sets a minimum of normally at least 16 degrees Celsius, falling to 13 degrees where much of the work involves rigorous physical effort. Unlike the upper end, the floor is stated as a figure.

Can an employee refuse to work because it is too hot?

Only in narrow circumstances. Sections 44 and 100 of the Employment Rights Act 1996 protect a worker who leaves a workplace in circumstances of danger reasonably believed to be serious and imminent. Discomfort does not meet that threshold, and the protection is tested at a tribunal after the event.

What must an employer do during a heatwave?

Assess heat as a hazard and apply proportionate controls, which can include ventilation and cooling, blinds and window film, relaxed dress codes, adjusted hours, rotation away from the hottest areas, additional breaks and access to drinking water. Pregnant, older and disabled workers warrant specific consideration.

Is the law on workplace temperature changing?

The Health and Safety Executive is reviewing the Approved Code of Practice for the 1992 Regulations, including temperature, and has signalled a public consultation. Unions are calling for a 30 degree ceiling and the Climate Change Committee recommended maximum temperature regulations in May 2026, but no threshold has been legislated.