Project #46643: Heating / HVAC

Due to issues with crawlspace air air quality. Our Heating/HVAC system has become compromised. Vents are in floors and ducting is located in crawlspace. Not sure if it needs cleaned or repaired. While running system for heat in winter or AC in Summer, crawlspace air can definitely be smelled in living area. We've been battling respiratory issues since we moved in. We just want a safe and healthy home. My husband and I are fully capable to contribute labor to the project and if possible, set up a low monthly pay over time agreement.