Blog
What Is the Maximum Temperature for a Classroom in the UK?
What is the real cost of school overheating? Explore how classroom temperatures affect learning and how temperature data can help schools prioritise action.
- October 2026
- 5 mins
There is no legally defined maximum classroom temperature in England. Schools must manage health and safety risks, but workplace law does not set a specific upper temperature limit. Department for Education guidance sets standards for ventilation and thermal comfort in school building design, including criteria for assessing overheating.
So, what temperature is too hot for a classroom? Twinview uses 24°C as a screening threshold to identify rooms that may need closer investigation. Evidence suggests that higher temperatures can affect concentration and cognitive performance, making classroom heat an important consideration for schools.
Twinview sensor data shows why the issue matters. Across 105 teaching spaces in three UK schools, a third of classroom days included some time above 24°C.
Is there a legal maximum temperature for classrooms?
No. In England, there is no specific legal maximum temperature for classrooms. However, several regulations and guidance documents address workplace conditions, school premises and thermal comfort.
The distinction is important. Building design guidance helps ensure that new school buildings meet appropriate standards for thermal comfort and overheating. It does not establish a single temperature at which every occupied classroom becomes legally unacceptable.
Schools must still consider the conditions pupils and staff are experiencing and take appropriate action when heat creates a risk.
What temperature is too hot to learn?
There is no single temperature at which every classroom becomes too hot for learning. However, research indicates that higher indoor temperatures can affect cognitive performance, including concentration and the ability to complete demanding tasks.
The HSE notes that uncomfortable thermal conditions can cause concentration to decline and increase the risk of errors. Research examining cognitive performance under warmer conditions has also found reductions in performance on some tasks as temperatures rise. The precise effects vary with the conditions, the task and the people involved.
This matters in schools, where pupils need to concentrate for sustained periods and teachers need to maintain a suitable learning environment.
Why does Twinview use 24°C?
Twinview uses 24°C as a screening threshold, rather than a legal limit or an official definition of classroom overheating.
The threshold provides a consistent way to identify rooms that may warrant closer investigation. It allows schools and estates teams to see how often temperatures rise above this level, which rooms are affected and how conditions change throughout the day.
It is important to distinguish this screening measure from a formal overheating assessment. Building Bulletin 101 uses more detailed criteria to assess overheating in school design, taking account of factors such as temperature exceedance and the relationship between indoor and outdoor conditions.
Air temperature alone also does not determine thermal comfort. Humidity, air movement, radiant heat, clothing and activity levels can all influence how hot a room feels.
For schools, the practical question is not simply whether a classroom crosses a particular threshold. It is whether the available evidence indicates that conditions need attention, and what can be done to improve them.
How often do UK classrooms go above 24°C?
Twinview's Too Hot to Learn? report examines temperature data collected by Twinview sensors across 105 teaching spaces in three anonymised UK schools.
The analysis covered 32,449 hours of sensor data across 51 common teaching days between 20 April and 13 July 2026. It examined temperatures during the school day, excluding weekends, the May bank holiday, half-term and known school closures.
The findings show how frequently monitored spaces exceeded the 24°C screening threshold.
The proportion of rooms above 24°C at 3pm was approximately 4.6 times the proportion at 9:15am.
This highlights an important pattern: temperatures can build as the school day progresses. A classroom that feels comfortable at the start of the day may be considerably warmer by the afternoon.
For school leaders, estates teams and facilities managers, this makes continuous temperature monitoring valuable. Rather than relying on occasional checks or general impressions, schools can use recorded data to identify which spaces experience higher temperatures and when those conditions occur.
The findings relate to the three schools included in Twinview's study. They should not be interpreted as a national estimate of classroom overheating across all UK schools.
What should schools do when classrooms get too hot?
Schools can take immediate steps to manage hot weather while using longer-term evidence to identify where building improvements may be needed.
1. Measure classroom temperatures
Use temperature monitoring to understand which rooms become warm, how frequently thresholds are exceeded and when conditions are most challenging.
Continuous readings provide a more complete picture than one-off measurements, which may miss periods of higher temperatures later in the day.
2. Manage sunlight and ventilation
Use blinds or other appropriate shading to reduce solar heat gains. Where possible, ventilate rooms when outdoor conditions are cooler than indoors, while maintaining adequate fresh air and following relevant ventilation guidance.
The right approach will depend on the building, its ventilation system and the conditions outside.
3. Adapt lessons and timetables
Where practical, consider moving activities to cooler rooms or adjusting the timing of more physically demanding lessons. Schools may also need to consider room temperatures when planning examinations and other activities requiring sustained concentration.
4. Protect pupils and staff
Make drinking water readily available, encourage appropriate hydration and consider the needs of people who may be more vulnerable to heat. Schools should also follow relevant hot weather and Heat-Health Alert guidance.
5. Use evidence to prioritise estate improvements
Repeated temperature readings can help identify buildings and rooms that may benefit from improvements such as external shading, better ventilation or other appropriate measures.
For estates teams managing multiple buildings, this evidence can help prioritise investigations and direct limited budgets towards areas where action is most needed.
These measures should be considered alongside the Department for Education's guidance for managing hot weather in schools and the school's own health and safety procedures.
Frequently asked questions
Can a school close because it is too hot?
There is no fixed temperature at which a school must automatically close. School leaders should assess the conditions, consider the risks to pupils and staff, and take appropriate action. Depending on the circumstances, this may include adapting activities, changing room use or considering whether the school can remain safely open.
Is there a minimum classroom temperature?
There is no single minimum temperature that applies universally to every classroom. The HSE's workplace guidance states that indoor workplaces should normally be at least 16°C, or 13°C where work involves rigorous physical effort. These are workplace guidelines, not a complete definition of suitable classroom conditions.
Can teachers stop working if a classroom is too hot?
There is no universal temperature at which staff automatically have the right to stop working. Concerns about excessive heat should be raised with school management so that conditions and health and safety risks can be assessed and appropriate measures taken.
Does 24°C mean a classroom is overheating?
Not necessarily. Twinview uses 24°C as a screening threshold to identify rooms that may need closer investigation. Formal overheating assessments use more detailed criteria, and air temperature alone does not determine thermal comfort or heat stress.
Can high classroom temperatures affect concentration?
Yes. Evidence suggests that higher temperatures and uncomfortable thermal conditions can affect concentration and performance on some cognitive tasks. However, the effects vary according to the individual, the activity and other environmental conditions. There is no single temperature at which every pupil's concentration will be affected in the same way.
How hot do UK classrooms get in summer?
In Twinview's 2026 study, 33.7% of classroom days across the monitored teaching spaces included some time above 24°C, while 18.5% included two hours or more above that threshold. These findings describe the three participating schools, not all UK classrooms.
About the data
The findings in this article come from Twinview's Too Hot to Learn? report, which examines temperature data collected by Twinview sensors across 105 teaching spaces in three anonymised UK schools.
The analysis covered 32,449 hours of sensor data over 51 common teaching days between 20 April and 13 July 2026. Weekends, the May bank holiday, half-term and known school closures were excluded. The analysis focused on temperatures during the school day, between 9:05am and 3:10pm.
The 24°C threshold is used as a screening measure to identify potential areas of concern. It is not a statutory temperature limit or the formal definition of overheating under school building design guidance.
The results provide insight into the conditions experienced in the participating schools and demonstrate how temperature monitoring can help identify patterns that may otherwise go unnoticed.
Explore the full findings
How often do classrooms exceed 24°C, and what can schools do about overheating as the climate changes?
Download Twinview's Too Hot to Learn? report to explore the findings in more detail, understand the wider research and discover a phased approach to addressing classroom overheating.
Ready to see Twinview in action?
Book a personalised demo to explore how we can help your organisation.