Comparing “apples to apples,” you will find that duct installation estimates permitted by the city and provided by licensed contractors will not vary a lot. The differences in estimates start to show when: Contractors are not licensed and perform the work illegally. This allows them to cut corners and use non-compliant materials that the permitting contractor can not. Projects are not permitted. Poorly designed and undersized air duct systems have a significantly shorter installation time and lower associated material costs. No warranty on installation. These poorly performing systems will cost the client far more in the long run due to premature failure, poor comfort and wasted energy from leaks and undersizing. Call us at (714) 332 – 6302 for more information.