HVAC Per Pound method and Per Piece Ductwork Estimating Process

There are several methods for calculating ductwork labor the most common of which are the per pond method and the per piece method. The per pound method calculates the cost of ductwork labor and materials per pound of ductwork based on a mixture of duct gauge sizes, straight duct and fitting types for typical ventilation systems. This method requires that an experienced individual calculates the typical mixture and type of ductwork for low medium and high pressure systems for a given system based on previous projects of a given type.  Variations occur if any of the typical factors for a given system fluctuate as it will cause the per pound cost of labor and materials to fluctuate up or down and can result in labor and material cost variations. Adjustment factors can be attributed to allow for variations.

The per piece method of estimating will capture the actual cost of labor and material expended for the specific type of ductwork and size of ductwork used in a system based on each unit comprising the ventilation system as it is based on unit components. The per piece method offers the most direct correlation between unit measurement and actual material and labor cost. It will compensate for a mixture of straight duct, fitting types, duct sizes and gauges as it looks at each unit component. The per piece method is based of unit cost requires an understanding of the variety of duct pieces involved in the system. It deals with quantities and understandable sizes and labor entities. The per piece method of estimating is based on the actual labor and material required to fabricate and install a certain duct type and size range by an average sheet metal mechanic taking into consideration production operations. The method is based on time studies for fabrication and installation of ductwork broken down into component operations in the production process. While this method is more detailed and requires unit fabrication and installation time studies it will result in greater estimating accuracy. We will cover the process for calculating labor cost by unit component per piece estimating in a separate post.

Topics: Estimating Labor Cost