Schools where the temperature doesn't drop even with the AC on full blast. The cause? Classrooms without 'insulation' in the ceiling!?
Hello, this is Tasuki.
2023 has been the hottest year on record, with temperatures like 37.1°C recorded in Niigata Prefecture on September 17, 2023. It has been a year of lingering summer heat, and with the super El Niño phenomenon, it is even being called the era of 'global boiling'.
It is still so hot this year that we cannot let go of our hats and parasols...
Children have started the new school term, but there is a certain factor involved in why temperatures are too high in schools right now.
This time, I would like to think about a heat-related problem that is currently troubling schools.
I will also introduce an experiment that shows how much of a temperature difference there is just by having 'insulation'.
Many heartbreaking voices are coming from schools saying that the 'air conditioning is not working' because the lingering summer heat is too severe.There were even schools where the classroom temperature remained near 30°C despite having the air conditioning set to a low temperature.This was because the 'insulation' performance of the classrooms without countermeasures was low, causing the severe summer heat to be transmitted directly into the classrooms.
Citizen volunteers across Japan, feeling a strong sense of crisis, are gradually carrying out 'insulation' renovation work in school classrooms to improve the effectiveness of air conditioning, but the limitations are becoming apparent.
How effective is 'insulation' in the first place? An experiment to solve that question was held in late August 2023 during a workshop at Saitama City Omiya Elementary School.
In an experiment where glass wool, a type of 'insulation material', was placed on a 150°C hot plate, the children participating in the workshop brought their hands close to the hot plate. Then, voices of surprise were raised, saying, 'It's not hot at all!'
When there is 'insulation', the heat from the outside temperature is less likely to be transmitted. By installing 'insulation' in the walls and ceilings of classrooms, it is difficult for the outdoor heat to enter the room in summer, allowing you to maintain coolness. In winter, you can maintain the warmth of the room.
The workshop was organized by the NPO [Environmental Network Saitama]. The principal of another elementary school in Saitama City also participated in the workshop at Saitama City Omiya Elementary School. He stated, 'I participated in the workshop because I wanted to lower the classroom temperature for the children, even if just by 1°C or 2°C.'
What he was watching intently during the workshop was the process of making light-shielding panels by hand using materials that can be cheaply obtained at home centers. He said that there are no plans for 'insulation' renovation work at the elementary school building where he is assigned, and added, 'In any case, the air conditioning in the classrooms doesn't work. I feel sorry for the children who are enduring the heat...'
According to Associate Professor Masayuki Mae of the University of Tokyo, who is an expert on building 'insulation', the classrooms where the heat is particularly severe are those on the top floor, where the heat from the roof is transmitted directly.
In a classroom measured on a midsummer day, even with the air conditioning on at a low setting, the room temperature barely dropped from over 30°C, and even after some time had passed and the cold air blowing from the air conditioner had dropped to about 10°C, the room temperature ultimately did not fall below 28°C.
On extremely hot days, the lack of 'insulation' causes the temperature of the school classroom ceiling to exceed 40°C, creating a harsh environment where the heat feels like it is beating down directly on your head.
As a result of removing the walls and ceiling panels of the top-floor classrooms to insert 'insulation' and installing panels on the windows to reflect sunlight, the room temperature in the classrooms dropped by 5–6°C compared to before the 'insulation' was installed.
'Insulation' In a questionnaire survey of children after the renovation work was completed, comments were received such as, 'It's cool and I can concentrate on class,' and 'Before, the classroom was stuffy and hot, but after the renovation work to insert 'insulation', the classroom feels 'crisply' cool.'
If the classroom temperature becomes less affected by outdoor heat and cold due to 'insulation' renovation work, it will lead to savings in heating and cooling costs. Associate Professor Mae of the University of Tokyo, an expert on building 'insulation', strongly argued, 'By carrying out 'insulation' renovation work, classrooms can maintain comfort and electricity bills for air conditioning can also be reduced.'