Today, utility computing and Computing on Demand (CoD) could be parallelized to Grid computing because the latter is the best available technology to enable computing power as a massively available utility. In the present paper, iWatt, a naïve linear measurement for CoD services is introduced. The innovative feature of iWatt is considered to be the fact that facilitates both a consumption assignment to a Grid-ready service and a producing capability to CoD infrastructure in an analogous way to electric power device-network interaction.