Final Case Study Report [.pdf, 324 KB] March 2005
As new homes become more and more air-tight, providing fresh air through controlled ventilation systems is increasingly important. Partnering with a nonprofit developer (Claretian Associates), a nonprofit builder (South Chicago Workforce), and the Illinois Department of Commerce and Community Affairs (DCCA), PATH is monitoring and assessing the performance of three different ventilation systems in new affordable housing units in South Chicago.
New Homes of South Chicago III is one of the latest developments of Claretian Associates, a nonprofit community development corporation in South Chicago. The builder, South Chicago Workforce, is a nonprofit group dedicated to providing affordable homes with quality, energy-efficient construction, low utility bills, and access to public transportation. The motivation is that improved energy efficiency makes homes more affordable, especially for low- and moderate-income people. New Homes III will consist of 25 energy efficient homes featuring:
- Structural Insulated Panels (SIPs) with wall R-values of 24.7
- Condensing, sealed-combustion furnaces
- 1.2-kW photovoltaic systems (on 12 units)
- Low-e glazing
- Many recycled content materials
- Low-VOC paint and finishes
- Recycled content carpet and carpet pad with minimal outgassing
- Finger-jointed lumber and molding for interior walls and finishes
- ENERGY STAR qualified appliances
- Compact fluorescent lighting
- Controlled mechanical ventilation systems
The Illinois Department of Commerce and Economic Opportunity (DCEO) is funding some of these green features. The additional cost of all green features is approximately $4,000 per home. DCEO is also funding ENERGY STAR testing and evaluation of the homes in partnership with Domus Plus. PATH is partnering with Domus Plus to expand the scope of the testing and monitoring. On behalf of PATH, Steven Winter Associates, Inc. (SWA), is evaluating three separate ventilations systems and their impact on indoor air quality, comfort, and energy consumption. Working through the Department of Energy's Building America program SWA is also assisting the developer to incorporate solar energy systems.
1. The standard ventilation in the New Homes is the Air Cycler system. This system includes a duct running from the return plenum to the outdoors, so that when the air handler runs, fresh air is drawn in through the duct, mixed with return air, conditioned, and distributed through the duct system. To prevent excess unconditioned air from entering the home, the Air Cycler controller will operate a damper in the outside duct that will close if the outdoor air volume requirement has been met. Similarly, during periods of low load, the controller will turn on the air handler fan periodically to guarantee fresh air requirements are met.
2. A manufacturer of Heat Recovery Ventilation equipment (HRV) has offered a system at reduced cost for evaluation in New Homes III. The HRV system both draws air in and exhausts air out of the home, and in the process transfers a significant amount of energy from one air stream to the other. The system offers potential for greater energy savings but at a higher initial cost.
3. The third and most simple system is exhaust only ventilation. Two high-performance bathroom exhaust fans were installed on timer controls. While this system may not distribute air as evenly and effectively as other systems and it does not have any heat recovery, its cost is much lower and the energy it requires to operate is lower than the other systems.
See the project profile for construction photos and status.
Content updated on 11/20/2006