A method of measuring pressure includes the steps of (1) providing a vacuum cabinet with a storage compartment and an insulating space, and three temperature sensors; (2) sensing a first temperature level of an interior wall of the storage compartment; (3) sensing an ambient temperature level within the storage compartment; (4) sensing a second temperature level of an exterior wall of the storage compartment; (5) calculating an overall heat transfer coefficient (Q) using the ambient temperature level, the first temperature level, and a convective heat transfer coefficient for the interior wall of the storage compartment; (6) calculating a temperature differential between the second and first temperature levels; (7) determining a conductivity level (K) using the temperature differential, the overall heat transfer coefficient (Q) and a thickness of the insulating space; and (8) determining a pressure level (P) within the insulating space using the conductivity level (K).