To better understand the effect of indoor environmental conditions on primary and secondary student performance, measurements over six school days were logged in each of 220 classrooms at schools in the midwestern region of the United States. Results from statistical analyses demonstrate the effects of classroom conditions on student achievement scores. Specifically, structural equation modeling has been used to determine the effects of classroom speech levels, non-speech levels, and room reverberation conditions on math and reading achievement, while controlling for student demographics. Information regarding heating, ventilation and air conditioning (HVAC) system types was also gathered in each classroom. The focus of this paper is to report on the correlation between HVAC system type and the measured speech or non-speech levels in classrooms during the school day. Additionally the correlations between measured acoustic and indoor air quality parameters over time are presented, with specific regard to how HVAC system type might affect the correlations.