A thermo-absorption model for calculation of the heat transfer is proposed and experimentally validated for a laser directed energy deposition process. The bulk absorption (ß) may be defined as the ratio of the total power absorbed by the substrate (Pabs) to the laser power presented to the substrate (Pi). When combined with a value for exposure time, these terms may describe the energy absorbed and energy presented, respectively. The laser energy presented to the substrate may be accurately measured with a beam calorimeter, while the energy absorbed by the substrate can be obtained through process calorimetry measurements. Alloys Ti-6A1-4V and Inconel 625 were both evaluated using the process, and the tests were conducted at laser powers ranging from 1 kW to 2 kW. Experimental results determined the bulk absorption coefficient for the process with and without powder flow during laser deposition.