Workplace Temperature Law: The Minimum Myth, the Missing Maximum, and the Duty That Actually Applies

Twice a year, the same two questions sweep through UK workplaces. In winter: "Isn't there a legal minimum temperature? Can we go home if it's under 16 degrees?" In summer: "What's the legal maximum? Surely we can't be made to work in this?" Both questions assume the law works by thermometer, and both get confidently wrong answers passed around, so this guide settles them properly: the minimum that is not quite what people think, the maximum that does not exist at all, and the single duty underneath both that employers actually have to meet.

This is one of those areas, like the 25 kilogram "lifting limit," where workplace folklore has replaced the actual rules, and the folklore fails in both directions: it lets some employers believe a number on a thermostat discharges their duty, and it leaves some workers demanding rights the law never wrote. The HSE's workplace temperature guidance is the authoritative source, and here is what it actually says.

The cold side: the 16 degree "minimum" and what it really is

The famous figure is real, but its status is not what the folklore claims. The approved code of practice supporting the Workplace (Health, Safety and Welfare) Regulations 1992 says the temperature in indoor workplaces should normally be at least 16 degrees Celsius, or 13 degrees where much of the work involves severe physical effort. Those are the numbers everyone half-remembers.

Here is the nuance the folklore drops: these are guidance figures describing what "reasonable" normally means, not an absolute statutory limit with an automatic consequence. There is no law that says work stops at 15.9 degrees, and equally, hitting 16.1 degrees does not discharge the employer's duty if people are genuinely too cold to work safely and comfortably. The figures are the benchmark for the real obligation, which we will come to, and a workplace persistently below them is a workplace whose employer will struggle to argue it is meeting that obligation.

What the cold question usually reveals in practice is not a legal gap but a management one: heating that fails every winter, doors that stand open onto loading areas, and nobody assessing the cold spots people have complained about for years.

The hot side: the maximum that does not exist

Now the summer question, and the answer that surprises people: there is no legal maximum working temperature in the UK. None. The code of practice sets the minimum benchmarks above but deliberately sets no upper figure, on the reasoning that a single number cannot fit a bakery, a foundry and an office alike. Campaigns have long argued for a statutory maximum, but as the law stands, no thermometer reading legally ends the working day.

That is not the loophole it sounds like, because the absence of a number does not mean the absence of a duty. Heat is a genuine health risk, from discomfort and plummeting concentration through to heat exhaustion, and the employer's obligation to provide a reasonable working environment applies in a heatwave exactly as it does in a cold snap. An office at 32 degrees with no ventilation, no water and no adjustments is not lawful merely because no maximum was breached; it is an employer failing the actual duty while pointing at a rule that was never the rule.

The real rule: one duty, no thermometer

Strip away both myths and one obligation remains: employers must provide a reasonable indoor temperature, and more broadly a reasonable working environment, assessed like any other workplace risk. Reasonable is judged against the work being done, the people doing it, and what can sensibly be controlled, which is why the law resists single numbers, and why the HSE frames the issue as thermal comfort, a product of temperature, humidity, air movement, clothing and the physical demands of the task, not a thermostat reading alone.

Framed that way, the twice-yearly argument dissolves into a familiar discipline: identify where and when your workplace runs too cold or too hot, assess who is affected and how badly, and control it. Temperature is a risk to manage, not a threshold to litigate, and the businesses that grasp this stop having the argument every January and July.

What managing it actually looks like

On the cold end: functioning, maintained heating; draught control where doors and loading areas leak winter into workspaces; local heating for the cold spots a walk-through finds; sensible relaxation of dress expectations; and warm-up breaks and suitable clothing where work is genuinely cold by nature. On the hot end: ventilation and air movement before air conditioning is assumed impossible; shading on glazed elevations that turn offices into greenhouses; relaxed dress codes and flexible hours in hot spells; cold water freely available; and extra care for the people heat hits hardest, including pregnant workers and those with health conditions.

And on both ends, the same system underneath: temperature complaints treated as reports rather than moans, the recurring problems assessed and fixed rather than survived annually, and the arrangements written down where a health and safety audit can find them. A business that logs "too cold" complaints every winter in the same corner and does nothing has, in that log, written the first exhibit against itself.

The international wrinkle

The UK's no-numbers approach is one philosophy; other countries chose differently, and some jurisdictions do set specific workplace temperature figures or heat-stress rules, with several introducing new heat rules as summers intensify. For businesses with people in several countries, that means the honest answer to "what temperature applies here?" genuinely varies by jurisdiction, which is exactly the patchwork international health and safety consultants manage, holding one world-class standard for thermal comfort while meeting each country's specific rules, aligned with frameworks such as ISO 45001.

And at any scale beyond one building, the discipline is systemic: which sites run hot, which run cold, what was assessed, what was fixed and what remains, visible in one place rather than buried in each site's grumbles. That is where consultants and software carry it together, with qualified health and safety consultants making the reasonableness judgements and the platform keeping every site's picture current.

The two questions, answered for good

So, for the winter meeting: there is a benchmark of 16 degrees (13 for heavy physical work), it is guidance defining "reasonable" rather than an automatic stop-work line, and an employer ignoring it is failing the real duty, not a technicality. And for the summer meeting: no maximum exists, and that fact rescues no employer, because the duty to provide a reasonable environment never took the day off. Both answers point the same way: assess it, control it, evidence it, which is simply health and safety doing to temperature what it does to every other risk.

Where Arinite fits

Arinite has spent 15+ years replacing seasonal arguments with working arrangements. We support 1,500+ businesses across 50+ countries and have helped protect 100,000+ employees, with a 95% client retention rate. As global health and safety consultants, we help businesses assess and manage thermal comfort alongside every other workplace risk, consistently across every site and country.

If your workplace has the same temperature argument twice a year, that recurrence is the finding. Our free gap analysis reviews your arrangements and tells you plainly where you stand. Book your free gap analysis and retire the thermostat debate for good.