HVAC Effects On Classroom Performance

Energy savings, comfort and indoor air quality – these are the measurables by which we determine the success or failure of any commercial HVAC system. And while all three of these indicators are critical concerns for property owners and facility managers, they are particularly important when the occupants are young children attending school.

Over the past decade or so, various studies have been conducted in hopes of quantifying and highlighting the link between proper HVAC functioning in school buildings and the success of attending students. A review of some of the most recent findings may be surprising to some – definitely of importance to anyone enagaging in school building commissioning, engineering or retrofit projects.

In May 2013, researchers at Lawrence Berkley National Laboratory issued a report that looked at the role ventilation plays on student absenteeism. The study collected data from 28 elementary schools (162 classrooms) in three climate zones within California, over two school years. Carbon dioxide (CO2) sensors in classrooms were used to collect real-time environmental data, and the participating school districts provided student absence and demographic data.

After collecting and analyzing the data, the researchers concluded that higher ventilation rates (VRs) in classrooms were associated consistently with decreased illness absence. Keeping VRs below recommended levels in classrooms saves energy and money but, as the researchers point out, has a much larger cost from increased health problems and illness absence among students. The study also found that increasing VRs above the recommended minimum levels, even up to 15 L/sec-person or higher, may further substantially decrease illness absence.

As the study points out, “these findings suggest a potentially large opportunity to improve attendance and health of elementary school students in California through provision of the increased outdoor air ventilation in classrooms.”

It’s of interest to note that surveys of ventilation rates in existing schools typically fail to meet ASHRAE standards with as many as 88% of U.S. public elementary school classrooms exhibiting ventilation rates less than specified in codes. Concentration of CO2 in these buildings has often substantially exceeded 1,000 ppm, implying ventilation rates less than 7.4 L/sec-person.

Air Conditioning Factor

Proper air conditioning is also a factor when it comes to student achievement. Studies show that after a classroom reaches around 77 degrees or above, student concentration and cognitive abilities decline sustainably. And while proper air-conditioning is pervasive in office buildings throughout the U.S., it is much less common in classrooms where local temperatures can easily shoot up into the 90s and beyond.

In another report, “Greening America’s Schools: Costs and Benefits,” researchers reviewed 30 “green schools” and found that building performance upgrades cost on average 2% more to incorporate, but provide a return on investment of around $70 per ft2 – or nearly 20X. These savings appear in a variety of forms from lower energy and water costs, improved teacher retention and lowered health costs among others.

An excerpt from the study highlights the indoor air quality issues addressed through green building…

“According to the U.S. General Accounting Office, 14 million students (over a quarter of all students) attend schools considered below standard or dangerous, and almost two thirds of schools have building features such as air conditioning that are in need of extensive repair or replacement. This statistic does not include schools with less obvious but important health-related problems such as inadequate ventilation. A recently published document by the American Federation of Teachers notes that the General Accounting Office found that the air is unfit to breathe in nearly 15,000 schools.”

The costs of poor indoor environmental and air quality in schools, including higher absenteeism and increased respiratory ailments, have generally been “hidden” in sick days, lower teacher and staff productivity, lower student motivation, slower learning, lower test scores, increased medical costs and lowered lifelong achievement and earnings.

An analysis of two school districts in Illinois found that student attendance rose by 5% after incorporating cost-effective indoor air quality improvements.
A study in Chicago and Washington, DC schools found that better school facilities can add 3 to 4 percentage points to a school’s standardized test scores, even after controlling for demographic factors.
A recent study of the cost and benefits of green schools for Washington State estimated a 15% reduction in absenteeism and a 5% increase in student test scores.
And these are just a few examples sited in the report.

Energy savings, comfort and indoor air quality – these are the measurables we use to evaluate HVAC system design and performance. But they are broad terms used for real world differences, such as the extra budget needed to hire additional teachers, improved test scores and reduced health-related absenteeism.

Now, armed with the data from a growing number of quantitative studies, building engineers, commissioning agents and other contractors are partnering with school districts looking for real improvements. Meeting building code is just the beginning. Aiming for real improvements in HVAC systems and other building performance criteria, these experts are proving that it makes sense to do it right.

Written By,
Building Solutions