Arrived on site to troubleshoot a musty odor from the system. When we arrived the client who scheduled the call was at work and unavailable by phone. We met the grandmother at the home who was watching the kid and she didn’t have a ton of background of information on where the smell was coming from or which areas in the house was affected. We told her that we would go through each system thoroughly in attempts to identify the causes for the smell and we completed a comprehensive evaluation of the main floor and upstairs unit. The systems were installed in 2024 and have no mechanical failures. The drains are flushed, filters are changed and the system are heating and cooling within all manufactured specifications. The duct work is original to the home, plenums have dust and debris and there are no indoor air quality enhancements to help mitigate dust, odors, pathogens and VOCs. The return grills are very dusty and some duct cleaning, indoor air quality improvements would help considerab