ICRT finds simple solutions to indoor air quality


ARI and Engineering Communications

Building Testing Technology in Use
Building Testing Technology in Use

Researchers in the Illinois Applied Research Institute ‘s Indoor Climate Research & Training (ICRT) division have completed a field study to better understand the indoor air quality (IAQ) impacts of having an attached garage and how to best minimize the consequences.

ICRT is a leader in IAQ research, regularly studying the relationships between IAQ, energy efficiency, environmental pollution and human health in the context of residential buildings. The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) selected ICRT as the lead for a more than $200,000 sponsored research project to study the magnitude and mechanisms of contaminant transport from attached garages into homes.

 “Attached garages are sources of significant air contaminants, such as carbon monoxide, which can be a major indoor air quality concern,” said Paul Francisco, Senior Coordinator of ICRT and principle investigator for the project. “These contaminants can get into the living space via bypasses at the garage-house interface through an intermediate space such as an attic or by mechanical systems such as forced-air furnace ductwork.  This project allowed us to evaluate the effectiveness of different approaches to keep the contaminants out of the living space, which should help avoid related health problems in homes.”

In collaboration with partners at the Center for Energy and Environment and The Energy Conservatory, ICRT designed and executed a field research study of five homes in central Illinois with differing characteristics and attached garage configurations. Progressive temporary and permanent interventions were applied to the buildings including air-sealing, passive ventilation and mechanical ventilation. The changes in building performance from these interventions were quantified using building diagnostic equipment to measure the inter-zonal building connectivity and the tracer gas to track the movement of garage air.

“The findings suggest that there are some simple solutions that can have a large impact on garage-house connectivity, such as air sealing crawlspace access hatches located in the garage,” Zach Merrin, ICRT Research Engineer and project manager of the study said. “Situations where a forced-air HVAC system is located in the garage present a more difficult challenge, and require moderate flow mechanical ventilation of the garage to overcome pressures induced by leaks in the HVAC system.” 

The study concluded that a continuously operating exhaust fan with a capacity of ~100 CFM per car bay should be sufficient in most situations where there are not excessive bypasses between the garage and the living space. These findings may influence future standards, codes and policies that deal with residential ventilation rates and requirements.

The research was presented and well received at the 2016 ASHRAE IAQ conference in Alexandria, VA, and to the Ventilation and Acceptable Indoor Air Quality in Residential Buildings Standing Standards Project Committee during the 2017 ASHRAE winter conference in Las Vegas. The work was also featured in the article "An evaluation of strategies to reduce transport of pollutants from garages to homes" in the journal Science and Technology for the Built Environment.

In addition to the academic and policy impacts of this research, the project had a much more tangible local impact in the form of no-cost improvements for participating households. The most serious issue discovered and corrected during the project was an HVAC return plenum in a home’s crawlspace that had been destroyed by moisture from a failed dryer exhaust. This caused the HVAC system to bring musty crawlspace air and lint-filled dryer exhaust into the living space. 

The homeowners, who were acutely aware of the effects but unaware of the root cause of the issue, were using whole house air fresheners (a practice that ICRT does not recommend) in an attempt to conceal the odor. After alerting the homeowner to the source of the issue and how to fix it, a local contractor rectified the situation, and the research sampling was able to resume.