The relationship between indoor air quality (IAQ) and the K-12 student experience has been a topic of study for decades. Researchers have found that creating a comfortable, well-lit, and sufficiently ventilated classroom is critical to learning. Not only can a quality environment have a measurable impact on student health, attendance and performance, it can also give educators a competitive advantage in the recruiting and retaining of teachers. As a result, many K-12 districts across the country have taken steps to improve indoor air quality by upgrading the HVAC units within their buildings. Yet, new research suggests these schools may not be getting what they paid for.