What is the Maximum Legal Working Temperature in a UK Office?

When the summer heatwave hits and the office thermometer creeps past 28°C, the same rumour always spreads among the staff: "If it hits 30 degrees, they legally have to send us home."

If you are an employer, an office manager, or an HR director, you are probably scrambling to figure out if this is true and what your actual legal liabilities are.

Here is the definitive answer on UK workplace temperature laws.

The Myth of the Maximum Limit

Despite what your employees might tell you, there is absolutely no maximum legal working temperature in the UK.

According to the Health and Safety Executive (HSE), there is a recommended legal minimum (16°C for an office environment, or 13°C for physical work), but there is no legal ceiling.

Whether the office is 25°C or 35°C, there is no specific temperature trigger in UK law that forces a business to close its doors and send staff home on full pay.

The "Reasonable" Loophole

However, you are not entirely off the hook. While there is no strict maximum number, the Workplace (Health, Safety and Welfare) Regulations 1992 state that employers have a legal duty to provide a "reasonable" temperature in the workplace.

Heat is officially classed as a workplace hazard. If your staff are complaining about the heat, you are legally obligated to carry out a thermal risk assessment. You cannot just tell them to drink water and get back to work.

If an employee faints or suffers heat stress because you failed to take practical steps to manage the temperature, you are entirely liable for a health and safety breach.

What Employers Must Do

To comply with the law and protect yourself from HSE complaints, you must demonstrate that you are taking active steps to manage the heat hazard.

This includes:

• Relaxing the dress code: Stripping back requirements for ties and heavy suit jackets.

• Providing cold water: Ensuring staff have unrestricted access to hydration.

• Managing airflow and temperature: The HSE explicitly lists providing fans and local cooling equipment as a required practical step to mitigate heat risks.

The Hidden Cost of the Heat

Even if you are not legally forced to send them home, allowing your office to bake is financially disastrous.

When office temperatures cross 26°C, cognitive function drops dramatically. Errors increase, lethargy sets in, and productivity plummets. You are essentially paying your staff their full hourly wage to sit at their desks, sweat, and complain to each other about how hot it is.

If you want your business to actually function during a heatwave, you need to mechanically break the heat.

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