There's no legal minimum or maximum temperature
Schools should follow government guidance on workplace temperatures, which requires a 'reasonable' indoor temperature. For classrooms (i.e. places where people aren't doing physical work) the guidance says this is a minimum of 16ºC.
There's no guidance on maximum temperature, but your emergency or critical incident plan must cover 'severe weather' – for example, heatwaves.
You're legally required to keep classrooms at a 'reasonable' temperature
This is set out in the Workplace (Health, Safety and Welfare) Regulations 1992 (section 7).
You're also required to:
- Provide sufficient thermometers so that employees know what the temperature is
- Make sure your heating and cooling systems are safe and won't cause injury
The Health and Safety at Work etc. Act 1974 requires employers to ensure the health, safety and welfare of their staff and others. Classrooms and other school spaces that are too hot or too cold may put the health of teachers and pupils at risk.