How Can Schools Mitigate Overheating in a Warming Climate?

Overheating in classrooms is becoming increasingly problematic for schools in the UK with climate change.

This is why the Department of Education (DfE) issued guidance last summer after some schools have had to close because of rising temperatures.

Overheating causes a myriad of problems for both students and teachers who find it hard to concentrate when the mercury rises beyond 26C, the maximum classroom temperature recommended by the National Education Union (NEU).

Both physical and mental health is affected especially for younger children and children with SEND who may not be able to express how they are feeling.

Better insulated schools trap heat

Much of the problem of overheating lies with the way schools are designed.

Research by the Met Office with University of London on data of 20,000 schools in the UK revealed that those built after 1960 onwards were more likely to overheat than older buildings because they are better insulated

Design features like double glazed windows which don’t open very far because of safety requirements, mean there is nowhere for solar glare to escape, especially if classrooms are south and west facing.

However, there are measures schools can follow so children’s learning is uninterrupted.

Adapt spaces and the school day

Use other spaces for temporary classrooms that aren’t south or west facing to avoid overheating.

If the heatwave is expected to last for a while, start and finish the school day earlier as well as introducing earlier play times.

Relax dress codes

The DfE advises strict dress codes need to be relaxed for children and teachers during heatwaves.

Ditch blazers, jackets and ties and allow everyone to wear loose, light-coloured clothing to help keep cool.

Keep windows open and closed at appropriate times

Open windows at night and early mornings to let cool air in though this may not be possible if it goes against insurance conditions.

Early morning is also a good time keep doors and windows open to allow cross ventilation.

But when the air outside becomes warmer than inside, you need to close windows or else the classroom will heat up even more.

Turn lights off

It’s surprising how much heat lights and electrical appliances – especially those being unused or on standby mode – can generate so it’s a good idea to turn these off.

The biggest heat generators are desktop computers and printers so make sure they are switched off at the plug.

Mechanical cooling

Fans are good at keeping us cool but as soon as the thermometer hits 35C, they will blow hot air around and could increase dehydration causing heat related illness and exacerbating health problems.

Although air conditioning is effective in treating the consequences of overheating, it’s not a sustainable option for schools moving to Net Zero in 2030 which are expected to slash their carbon emissions.

As well as being highly polluting, air con is a huge energy guzzler and is therefore a very expensive option for schools struggling with ever increasing energy bills.

Close windows and curtains and blinds

The DfE and UK Health Security Agency advises schools should shade windows wherever possible and you should close curtains and blinds as soon as the sun hits the windows.

Lighter coloured curtains and internal blinds with heat reflecting finishes will stop the sun shining into the room but they won’t stop the solar glare passing through the windows and heating the room.

External shading is the best solution

External shading such as blinds and shutters have been used in schools in Europe for many years as a long-term solution to overheating.

They are the most effective and sustainable way of stopping the problem of overheating in the first place which is why the Government’s Climate Change Committee has called for their greater use.

They work by blocking the sunlight before it reaches a window, ensuring the room remains 40 per cent cooler than without any shade.

Let there be light while remaining cool

External blinds still allow light into the room so you won’t need to use artificial light and you can still see outside thanks to their special weave.

They can be controlled remotely too and fitted with sensors to automatically lower at a set temperature ensuring classrooms remain at an optimum temperature for learning.

Experts at shading

Kensington Blinds have more than 40 years of experience in providing sustainable and bespoke shading solutions.

If you would like to find out more about how external blinds work and talk about your needs, please contact us.