Inspected the ductwork and detected no significant leakage; howbeit the ductwork is not in great condition, and is leaking in some capacity throughout. There is indeed a detectable odor coming from the vents that smells eerily similar to that of the crawlspace. Ideally moving forward the ductwork should be replaced, as itâ€™s condition is not comparable to the newly installed equipment outside. Additionally, it is advised to have the crawlspace sealed by a professional. This improvement will serve to benefit the home in many more ways than one, and should not be over looked. It is advised to consult a crawlspace specialist, and moving forward be in touch in regard to the replacement of the ductwork.