Combating odor-causing mold and mildew to raise HVAC efficiency.

Contaminated air handling systems can spread odor-causing mold and mildew and hinder system efficiency. Extensive testing has shown Antimicrobial Copper can help.

Heating Ventilating and Air Conditioning (HVAC) system components operate in warm, dark, humid environments that are ideal breeding grounds for mold and mildew that cause odors and can inhibit system efficiency. Laboratory testing¹> on odor-causing mold and mildew has shown that copper materials can inhibit the growth of these organisms. After 24 hours of exposure to copper surfaces, total die off was observed in several common mold species. Aluminum had no effect on any of the fungi. These findings show the advantage over aluminum surfaces because of copper's inherent ability to inhibit the growth of odor-causing mold.

To support the laboratory data, a pilot-scale system was constructed at the University of South Carolina, funded by the Department of Defense (DoD) under the Telemedicine and Advanced Technology Research Center (TATRC). This program seeks to validate the concept of improved HVAC system performance through copper component use in these systems. The experimental setup will compare copper heat exchangers, drip pans and other components to their aluminum counterparts. Additionally, copper and aluminum coupons inserted in between heat exchanger fins will be removed periodically to observe biofilm growth. Data collection began in December 2009.

To observe the performance of copper air handling components in actual use conditions, a large scale test is underway in occupied military barracks at Ft. Jackson, South Carolina. Incoming data is evaluating the ability of copper heat exchangers to improve system performance throughout full heating and cooling cycles. For comparison, aluminum heat exchangers were installed in an adjacent barracks building. Additionally, energy consumption data is being collected to evaluate the relative efficiencies of the copper and aluminum systems. Copper heat exchangers are believed to be more efficient due to better heat transfer properties and corrosion resistance. Testing will provide long-term data in actual use conditions.

The US Environmental Protection Agency granted a "Treated Article Exemption" registration for copper alloys in HVAC applications in September of 2010.  This registration allows copper HVAC components to make product protection claims by suppressing the growth of bacteria and molds that reduce system efficiency and cause product deterioration or foul odors.  These claims are supported by EPA registration 82012-7.

[1] Weaver et al