Consumption of utilities (LN2, electricity and compressed air) over the usable life of a HALT\HASS system is typically many times the initial purchase cost of the equipment. For this reason, utilities cost are a key factor in determining the Total Cost of Ownership of a HALT\HASS system, and should be carefully compared prior to purchasing a HALT\HASS System. However, comparing utility consumption and costs are not easy. Different makers of systems use different methods of specifying utility consumption; some firms reportedly don’t even accurately measure consumption but rather provide simple estimates without substantiating data. The purpose of this document is to define a method for accurately and consistently measuring utility consumption of HALT\HASS chamber systems.