Project 2.4 - Envelope and IAQ Interactions

Objective

• To evaluate energy efficiency measures that can be implemented in housing for low-income households without exceeding indoor air quality (IAQ) standards.
  
• Measure carbon dioxide (CO2) and carbon monoxide (CO) concentrations in test homes that have whole house fans, evaporative coolers, ducts within conditioned space and an attic hot water pre-heater. Compare these measurements to those from control houses.
  

Prior Research

• Carbon dioxide concentrations can be used for understanding indoor air quality and ventilation. Energy Systems Laboratory (ESL) in Texas has been continuously monitoring indoor environmental conditions in a HfH house in Bryan, Texas for 18 months. Preliminary results indicate that although comfort conditions are being maintained, CO2 levels are routinely exceeding 1,000 ppm (parts per million by volume). Thus, there is a need to balance energy efficiency against indoor air quality impacts.
• The American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) recommends a ventilation rate of 0.35 air changes per hour (ACH) for new homes, and some new homes are built to even tighter specifications. Others suggest that particular care should be given in such homes to prevent the build-up of indoor air pollutants to high levels.
  

Task List

• Literature Review
  
• Evaluate Strategies to Reduce IAQ Impacts
  
• Prepare Monitoring Plan
  
• Apply IAQ Strategies to Nine Homes
  
• Monitor IAQ
  
• Analyze Data
  

Projected Outcomes

• Measure impacts various methods of envelope construction or system control have on indoor air quality as measured by the concentrations of carbon dioxide, carbon monoxide, and (in some cases) mold. IAQ measurements will quantify the improvements other elements that increased ventilation rates have on indoor air quality. Ventilation rates needed to maintain adequate CO2 levels and still be energy efficient may suggest the use of ventilation heat recovery. Yet the current technology is too costly for low-income homes.
  
• Technical goal is to achieve energy savings of 70 kWh per house per year.

Please visit the Project News and Public Documents page to view updates for this task, and current research activities.

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