What is the most recently added requirement for residential duct systems?

The most recently added requirement for residential duct systems is duct sealant. This requirement is crucial because effective sealing of ductwork helps to minimize air leaks, which can significantly improve the efficiency of HVAC systems. Air leaks can lead to unconditioned air entering or heated/cooled air escaping, causing systems to work harder, thus increasing energy consumption and costs.

The use of duct sealant not only enhances energy efficiency but also contributes to improved indoor air quality by reducing the potential for dust and pollutants to enter the duct system through gaps and cracks. Proper sealing also helps maintain consistent temperature and humidity levels throughout the home, contributing to overall comfort.

While insulation, fire-proofing, and sound attenuation are all important aspects of duct system design and installation, they are more established requirements and not the most recent addition. Insulation helps in reducing thermal losses, fire-proofing ensures safety standards, and sound attenuation focuses on minimizing noise transmission. Duct sealant stands out as a relatively newer focus in the pursuit of increasing efficiency and effectiveness in residential HVAC systems.