Optimal office temperature: More productivity, fewer errors

According to the German Workplace Ordinance (ASR A3.5) and scientific studies, the ideal office temperature is clearly between 20 and 22 °C.

This area promotes concentration and well-being and has been proven to protect health. In summer, the temperature should not exceed 26°C.

This gives you an immediate overview of the most important benchmarks.

This guide also explains why these figures are crucial, what legal frameworks apply, and what practical measures employers and employees can take to create a healthy and productive working environment.

What is the optimal temperature in the office?

The optimal office temperature is not a coincidence, but clearly defined:

• Ideal temperature range for office work: 20–22 °C
• Legal minimum temperature: at least 20 °C
• Recommendation for summer: not above 26 °C

These values ​​are derived from scientific studies and the workplace regulation ASR A3.5, which is binding for Germany.

They form the standard by which employers and employees can orient themselves.

But in everyday life, that's often not enough. Different temperature sensitivities within a team quickly lead to "thermostat wars." This guide addresses precisely this issue: You'll learn why these guidelines are so important for concentration and health – and how you can implement them in practice.

Why is the indoor climate in the office more than just a matter of feeling?

The temperature in the office is far more than a matter of personal preference. It directly affects productivity, concentration, and health – and therefore also the profitability of a company.

An unfavorable indoor climate is not only unpleasant, but also a measurable cost factor: employees work slower, make more mistakes and, in the worst case, are more frequently absent due to illness.

In short: The office climate is a crucial success factor that no employer should underestimate.

The direct line to performance: Temperature, productivity & concentration

Our brain functions like a high-performance computer – and just like technology, it needs the right "operating temperature".

• Too cold: The body constantly uses energy to maintain its core temperature.
• Too warm: The body fights against overheating.

In both cases, valuable energy is diverted from mental tasks. The consequences: declining concentration, increasing fatigue, and a higher error rate.

That this is not just a theory is demonstrated by a much-cited study from Cornell University: When the office temperature was increased from a cool 20°C to a comfortable 25°C, the error rate of employees decreased by 44%, while typing speed increased by an impressive 150%.

The finding is clear: A thermally comfortable office climate measurably increases performance and ensures that the brain can fully concentrate on work.

Impacts on health and well-being

A poor indoor climate not only affects mood but also directly impacts health – with clearly measurable consequences for well-being and the number of sick days.

• In winter: Cold, dry air from heating systems draws moisture from the mucous membranes in the nose and throat. This weakens the natural protective barrier against viruses and bacteria – making it easier for infections and colds to take hold.
• In summer: Prolonged heat puts a strain on the cardiovascular system. Typical consequences include headaches, dizziness, and severe difficulty concentrating.

In extreme cases, experts even speak of "sick building syndrome": Non-specific symptoms such as fatigue, irritated eyes or constant exhaustion can be directly attributed to an unhealthy building climate.

The conclusion is clear: investments in optimal office temperature are also investments in the health of the team – and pay off in the long run in the form of fewer sick days.

Legal framework in Germany: What ASR A3.5 prescribes

When it comes to office temperature, you don't need endless discussions or the goodwill of your employer.

In Germany, there are clear rules: The Workplace Ordinance (ArbStättV) and the associated technical rule ASR A3.5 “Room temperature” define in a binding manner what constitutes a healthy and acceptable indoor climate.

Minimum temperatures in the office – clearly regulated

The ASR A3.5 standard stipulates that certain minimum temperatures must be maintained in workrooms, depending on the activity. For typical office work, a clear standard applies: at least 20 °C.

Here is an overview of the official guidelines:

👉 For everyday office life, this means: The thermostat must never fall below 20 °C. Only then can it be ensured that concentrated work is possible without health risks.

Heat protection in summer: Rights and obligations for employers

The most frequent question during hot summer months is: "Do office workers have a right to a day off due to heat?"

The clear answer is: No, there is no general right to that.

However, the workplace regulation ASR A3.5 obliges employers to effectively protect their employees from the health risks posed by heat. A three-stage model exists for this purpose, specifying clear measures:

Stage 1: From 26 °C room temperature

• Keep rooms below 26°C if possible.
• Preventive measures: sun protection (blinds), night ventilation or closing windows early.

Stage 2: From 30 °C room temperature

• The employer must take action.
• Examples: Provision of free drinks, relaxed dress code, fans, flexible working time models (e.g. earlier start time).

Stage 3: From 35 °C room temperature

• The room is considered unusable without special protective measures.
• Work is only permitted with special measures such as heat breaks, air showers or technical cooling systems.

👉 In practice, this means that employers are obliged to take concrete steps to protect the health of their employees in high temperatures – even if there is no right to a “heat day off”.

The "temperature war" in the office: Why we perceive heat and cold so differently

Are you freezing while your colleague is already sweating? Almost every team is familiar with this scenario. But there's more to it than just personal preference: Our perception of temperature is individual and scientifically explainable.

Men vs. women: Not a cliché, but biology

It's true – women get cold faster on average than men. There are two main reasons for this:

• Metabolic rate: Women often have a lower basal metabolic rate. Their "internal engine" runs slower and produces less heat.
• Body composition: Men, on average, have more muscle mass, which actively generates heat. Women have a higher percentage of body fat, which provides insulation but does not produce heat.

Fun fact: Many air conditioning standards worldwide are still based on a model from the 1960s – designed for an average 40-year-old man (70 kg). No wonder, then, that many offices are systematically set too cold for women.

Other factors that influence our perception of temperature

But gender isn't the only factor. Other factors also determine whether we feel comfortable or chilly at 21°C:

• Clothing: A sweater can often make a difference of several degrees.
• Age: As we age, our metabolism slows down, our blood circulation deteriorates – and our sensitivity to cold increases.
• Physical condition: Fitness, weight and daily form (stress, fatigue) influence thermoregulation.
• Habituation: Someone who is used to warm rooms at home perceives a 21-degree office as cooler than someone who is adapted to lower temperatures.

👉 Understanding these differences is key to a harmonious work environment. It's not about who is "right," but about recognizing that everyone's body reacts differently – and that compromises are therefore unavoidable.

Practical solutions for an optimal office climate

Knowledge alone changes nothing – what matters is its implementation in everyday life. Fortunately, there are many practical ways to improve the office atmosphere.

Both employees and employers can actively contribute to transforming the "temperature war" into a healthy coexistence.

Tips for employees: How to improve your well-being

Even without adjusting the thermostat, you can influence your personal microclimate:

If it's too cold:

• Use the layered look: Wear several thin layers (T-shirt, shirt/blouse, cardigan) to be able to react flexibly.
• Warm from the inside out: Hot drinks or a warm soup during your lunch break will help immediately.
• Activate circulation: Stand up regularly, move around briefly or stretch – this promotes blood flow.
• Discreet helpers: A scarf, small blanket or fingerless gloves provide warmth without disturbing colleagues.

If it's too hot:

• Choose light clothing: cotton or linen are breathable and comfortable.
• Targeted cooling: Drink plenty of water; run cold water over your wrists.
• Use a mini fan: A quiet table fan creates a personalized microclimate.
• Proper ventilation: Ventilate by opening windows for 5-10 minutes instead of leaving them permanently tilted – effective and energy-saving.

Communication: The key to office harmony

Often, an open conversation is more effective than any action. Instead of accusations ("Who turned down the heating again?!"), a phrase like this works:

➡️ “I often get very cold in the afternoon, how about you?”

This way, common rules can be found – such as fixed ventilation times – that are acceptable to everyone.

Guide for employers and office managers

A good indoor climate is not a "nice-to-have", but an investment in the health, motivation and productivity of the entire team.

Employers and office managers can make a crucial contribution to avoiding conflicts and increasing satisfaction through clear rules and targeted measures.

Establish a clear temperature policy

• Define a standard value (e.g. 21.5 °C) that is based on legal requirements.
• Communicate this value transparently as a fair compromise for all employees.

Creating flexible solutions

• If the building architecture allows, establish temperature zones (e.g., places closer to or further away from window fronts or air conditioning units).
• Offer flexible seating options so that employees sensitive to cold and heat can find suitable seats.

More than just temperature: Holistic indoor climate

• Humidity: 40–60% is ideal. Hygrometers provide accurate readings; plants or humidifiers help to avoid dry air.
• CO₂ levels: In poorly ventilated rooms, the concentration drops rapidly. CO₂ measuring devices ("traffic light" indicators) clearly show when ventilation is necessary.

Promote open communication

• Take complaints seriously – they are not a luxury problem, but a legitimate factor in performance.
• Conduct regular mini-surveys about the indoor climate. This signals appreciation and shows that solutions are being actively sought.

👉 Conclusion for employers: Those who manage the office climate professionally not only create a healthier working environment, but also a team that is more motivated, productive and loyal.

And what about working from home?

The same applies at home: 20-22°C is ideal for focused work. The difference compared to the office?

You pay the heating costs yourself – but you also don't have to argue with anyone about the thermostat.

The biggest problem with working from home : Many people work at 17-18°C to save money. We know the consequences from the Cornell study: more errors, slower work. Those who skimp on heating pay the price in terms of performance.

Three simple rules for working from home:

• Heat at least your workspace to 20°C – the rest of the apartment can remain cooler.
• Cold feet? A small heated mat under your desk (20-40€) works wonders.
• Tilting windows is expensive – it's better to ventilate by opening windows fully for short periods, like in an office, 3 times a day.

Good to know: The home office allowance (€6 per day) also covers a portion of the heating costs.

With 100 days of working from home per year, that's a tax advantage of €600 – enough to cover the extra heating for the home office.

FAQ

What is the ideal humidity level in an office?

The optimal humidity level in the workplace is between 40% and 60%. Within this range, mucous membranes remain protected, the risk of infections decreases, and dust and allergens are significantly reduced.

Is there a right to a day off work due to heat?

No – there is no general right to a day off due to heat.
➡️ However: Above 30°C, the employer must implement protective measures (e.g., drinks, fans, flexible working hours). Above 35°C, an office without additional protective measures is considered unacceptable.

Am I allowed to use my own space heater at work?

In most companies, this is strictly forbidden. The reasons are fire safety and the risk of overloading the power grid.

👉 Before connecting a fan heater or other devices, always ask the facility management or your supervisor beforehand.

How do you ventilate properly in winter without cooling the room down?

The clear recommendation is: ventilate by opening windows fully for short periods instead of tilting them open.

• Turn down the radiator briefly.
• Open the window completely for 5-10 minutes.
• Then close the door and continue heating normally.

This allows stale air to be quickly exchanged without cooling down furniture and walls – efficient and energy-saving.

Conclusion

The optimal office temperature is not a minor matter, but a key factor for productivity, health and work ethic.

The scientifically established target range is 20 to 22 °C; in summer, the room temperature should not exceed 26 °C. The ASR A3.5 standard provides a clear legal framework for this, protecting both employees and giving employers legal certainty.

But numbers alone don't solve all conflicts. The human element remains crucial: differing physiological needs, mutual understanding, and open communication are the true key to a pleasant office environment.

👉 Ultimately, a good indoor climate is always a good working climate – and both benefit companies and employees alike.