–Which Are the Benefits of Air Conditioning for Students?

Children and teenagers, as well as senior students and teachers, around the world spend an average of 7 hours a day at school for over 180 days per year, according to a survey conducted by the National Center on Education and the Economy. Schools and universities are like second homes to many students, especially in South Korea where 220 days of school is the norm.

Naturally, their wellbeing and comfort in these facilities should be regarded with the same thoroughness as that of employees in the workplace.

Specialized institutions such as the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) and the Environmental Protection Agency (EPA) each offer guidelines (to which we will be referring below) to create optimal indoor air quality (IAQ) conditions in these spaces. However, in the case of USA, different districts or states have their own instructions for schools, which can differ from expert recommendations, resulting in standards that don’t always meet what’s recommended. This varies the world over. A World Health Organization (WHO) survey requested member countries in Europe to fill in a questionnaire on policies regarding school environment; only 45% of responding countries had IAQ standard practices for schools. In the US, according to the EPA, around 50% of schools do not have an IAQ management plan.

There is still much ground to be covered in terms of heating, ventilation and air conditioning (HVAC) regulations in schools and universities. For this reason, in this article, we aim to shed some light onto how the environment can impact students’ learning and performance, and how they can benefit from optimal air quality, with a Johnson Controls-Hitachi Air Conditioning case study, too. 

Indoor Air Quality in Schools

When measuring or monitoring indoor air quality, there are some key indicators to look for. The most common of these indicators is the presence of air pollutants and volatile organic compounds (VOCs). Some of these pollutants are chemicals released from cleaning agents, pesticides and paints, such as formaldehyde and benzene. Others can be naturally present in the air, but are toxic in higher concentrations, such as carbon dioxide (CO2). High CO2 concentrations are especially prevalent in high occupancy rooms, which is usually the case of classrooms. Other pollutants include mold and mildew spores, which thrive in humid environments, such as restrooms and changing rooms.

The higher the presence of pollutants, the poorer the quality of indoor air. EPA points out that 20% of schools in the US have reported unsatisfactory IAQ in 1999. The effects of these compounds on children’s health are magnified due to their developing immune systems. Some of those pollutants are also triggers for students with respiratory issues, such as asthma and allergies, increasing the rate of absenteeism from school. Common symptoms caused by poor IAQ include headaches, coughing and sneezing, and fatigue. Find out more about IAQ and its implications on children’s education in our article.

Ventilation in Educational Facilities

To improve indoor air quality, introducing fresh air indoors is crucial. This can be done through natural ventilation or mechanical ventilation. Ventilation can be measured through the air exchange rate (AER). The more air exchanges are performed per hour, the lower the concentration of indoor air pollutants will be. Excess moisture in buildings is also expelled through ventilation. The WHO survey mentioned above also found that most schools had stuffy classrooms due to poor ventilation, especially during winter, as a result of lack of proper heating. Additionally, a study assessing IAQ and ventilation in Michigan schools found that ventilation was inadequate in many of the schools, as only 27% of the classrooms achieved the ASHRAE standard of 3 air exchanges per hour.

A school’s ventilation strategy should take into account outdoor factors as well, such as weather, temperature, pollen count and pollution. This way, school environments can benefit from a combination of both natural and mechanical ventilation; resorting to mechanical ventilation when outdoor air quality is poor.

Certain areas, such as school cafeterias, art rooms or restrooms ideally need specialized exhaust ventilation systems. An effective exhaust ventilation eliminates pollutants from the room by vacuuming it and pushing it outdoors through vents. In schools, humidity, fumes from cooking, painting materials, and detergents can accumulate, making exhaust fans a necessity.

However, school buildings tend to have particular challenges that pose obstacles for an optimized HVAC system. Many times, public educational facilities are built with more affordable construction materials to lower expenses, or they are older buildings. In these cases, the options for effective HVAC system installation are reduced, as ducted systems may not be practicable in all building types, or space to install equipment may be limited.

What temperature is best for the classroom?

Determining the ideal temperature for a classroom is not straightforward, and it naturally differs by country and climate. The health effects of poor IAQ are quite notable, but what is equally concerning and less known is that the climate also impacts students’ academic performance. School absenteeism is a prevalent issue, which in turn affects pupils’ progress and their academic results. Chronic respiratory illnesses (such as asthma) are directly related to lack of attendance due to poor IAQ, but inadequate infrastructure and environment can also be a common cause.

- Thermal comfort. The concept of thermal comfort refers to the thermal sensation being just right, not too cold, not too warm. According to ASHRAE, classrooms should have a minimum temperature of 22ºC (72ºF) in winter and a 24ºC (75ºF) temperature in summer, with relative humidity of 40%-60%.

When facing extreme temperatures, such as heatwaves and cold spells, schools not equipped with proper HVAC systems have to stop activities and close classrooms. Increasingly hot summer days make it uncomfortable and stifling for students to attend classes in spaces without air conditioning, or attending on freezing days in winter without heating, leading to fewer students attending.

- Temperature and behavior. As data shows an increase of crimes on hot summer days, studies have started to notice a pattern that relates heat to irritability and short-temperedness. Students in hot classrooms may be more likely to show irritable behavior or negatively influence teachers’ perception of student behavior. Extreme temperatures are also related to lack of motivation, making it harder to focus on tasks as the body struggles to adapt to the temperature.

- Effects on academic results. The lack of thermal comfort directly affects learning, as indicated by the findings of a Harvard University study. Hotter countries tend to score lower on academic excellence tests, and through a standardized test in high schools without air conditioning the study’s findings go further. The results show that for every 1ºF (0.56ºC) increase in temperature, it lowers the student’s score equivalent to 1% of a year's worth of learning. According to another study conducted in Finnish schools, pupils who felt more comfortable scored 4% better than their peers.

Similarly, IAQ and ventilation also have shown some relation with academic results. In a study of 100 elementary schools in the US, with higher ventilation rates, students scored better and had more accurate picture memory and word recognition.

Energy Saving Recommendations

With limited resources and tight budgets, educational facilities can greatly benefit from an HVAC strategy that targets energy efficiency and reduces energy waste. Here are some recommendations for more energy efficient and greener HVAC systems in schools:

- Natural ventilation when possible. Encouraging natural ventilation through windows and doors helps to reduce humidity, VOCs, allergens and other pollutants from the facilities without any energy consumption. However, at times, it may not be safe to naturally ventilate, this is the case of allergy seasons or high pollution days, when outdoor air quality is worse than IAQ. Or during extreme weather days, when it is too hot or too cold to open the windows. For these cases, a hybrid ventilation system is the most effective, as it allows one to rely on mechanical ventilation only when needed.

- Fans. Installing child-proof fans in classrooms can increase the sense of cooling and comfort without lowering the temperature. A good example of efficient and classroom safe fans are ceiling fans, which can achieve a more even temperature around the classroom by dissipating hot air as it rises.

- Insulation. Maintaining thermal comfort and preventing moisture leakage can reduce further issues with temperature loss and humidity. Weatherproofing the building with insulation materials, and checking sealing around windows and doors can reduce energy consumption used for cooling in summer and heating in winter, as there is very little thermal loss.

- Selecting energy efficient AC systems. Taking the infrastructure into account to find the optimal solution for each case can save up on energy. Some systems offer better technology to increase efficiency and reduce consumption, such as heat recovery systems that reuse exhaust heat to provide heating.

What type of air conditioner to install in schools?

Though each school has its particular needs, the Hitachi Variable Refrigerant Flow (VRF) range offers ideal solutions for educational facilities. Variable refrigerant flow systems automatically adjust the amount of refrigerant flowing to each indoor unit, resulting in better temperature control. These systems offer cooling and heating to multiple spaces, with multiple indoor units connected to only one outdoor unit. Versatile and efficient, VRF systems allow for the installation of different types of indoor units, such as wall-mounted, cassette, ducted… The user-friendly controls and customization improve experience and efficiency from space to space.

Heat Recovery in the Hitachi VRF range allows simultaneous heating and cooling of different spaces, and is even more energy efficient as it transfers exhaust heat from cooling one room to provide heating to another room. Find out how Hitachi VRF Heat Transfer works and its advantages in different spaces in our article.

The Benefits of Air Conditioning in Education

As you have seen, there is clear evidence as to why schools, colleges, universities and other education facilities should take advantage of air conditioning for better student comfort and performance and put a HVAC strategy in place.

A prime example of this is also one of our case studies, that of North Kellyville Public School in Australia. The school qualified to be part of the initiative of the Cooler Classrooms Program being run by the NSW Department of Education to improve the learning environments of schools where average max temperatures in January reached 30°C and above. A Hitachi VRF system consisting of 24 Set Free Σ (Sigma) VRF units was designed to adapt to the school’s facilities, to provide comfort as well as Hitachi’s high energy efficiency and controllability. Despite the obstacles, such as the need to remove the existing suspended ceiling, North Kellyville K-6 students are able to enjoy learning during the Australian summer comfortably.

Find out more about the Hitachi VRF range and the benefits of a fully flexible system here.