A standard home inspection rarely evaluates duct condition, ventilation, or insulation in depth — yet they drive comfort, energy bills, and air quality. For buyers, a quick assessment flags hidden costs; for sellers, it's worth disclosing known issues up front.
Before you buy: what to inspect
Ducts & ventilation
- Duct cleanliness and any disconnected runs
- Asbestos-wrapped ductwork, common in older Southern California homes
- Adequate return air and balanced airflow room to room
- Bath and kitchen ventilation that actually vents outside
Insulation & moisture
- Attic insulation depth, even coverage, and air sealing
- Signs of moisture, mold, or past water intrusion
- Rodent contamination or degraded insulation
- Whether attic ductwork is sealed and insulated
Before you sell: California point-of-sale items
California requires certain items to be addressed when a home changes hands. Confirm the specifics with your agent and local jurisdiction.
What sellers should prepare
- Disclose known mold, moisture, or past water-intrusion issues
- Note any asbestos-related materials identified in the home
- Address obvious ventilation or duct problems before listing
Concerned about the air in a home you're buying or selling?
Frequently asked questions
Does a home inspection check the ductwork and air quality?
Only superficially. A standard inspection won't assess duct sealing, return air, or insulation against spec — the things that actually shape comfort and air quality. A focused look fills that gap.
Why does old ductwork matter when buying?
Leaky, undersized, or asbestos-wrapped ducts undercut even a brand-new HVAC system and can be costly to remediate. Knowing their condition helps you plan and negotiate.
Can poor insulation really affect my bills?
Significantly. Gaps, compression, and missing air sealing let conditioned air escape, so the system works harder. It's worth knowing before you buy.
Reviewed by John Stevenson Plumbing, Heating & Air. Based on how we assess ducts, ventilation, and insulation alongside HVAC work in older and newer Southern California homes. Disclosure obligations vary — confirm specifics with your agent and a qualified specialist for mold or asbestos. Last updated 2026-06-25.