HVAC retrofit for healthy schools

The Environmental Protection Agency has evaluated the impacts of HVAC systems and building dynamics on radon concentrations in 26 schools across the United States. Diagnostic data indicated that radon was not the only indoor air pollutant in these schools. As a result, an essential step in the School Evaluation Program is determination of the feasibility of using HVAC technology for radon remediation in addition to general indoor air improvement. In 1990, the EPA sponsored the HVAC retrofit of two schools in Maine. This paper presents the information gained by these case studies. First, the extensive pre-retrofit diagnostics and characterizations of the two schools are reviewed. Then follows a discussion of why and how the HVAC systems, including unit ventilators, central air-handling units, and heat recovery ventilation, were retrofitted. Finally, an appraisal of the post-retrofit radon and CO2 levels is made, along with presentation of related data such as retrofit costs and energy and comfort impacts