Field and laboratory tests have been performed to analyse the response of showcases to environmental factors. The following properties have been tested. Thermal damping. Greenhouse effect and IR absorption of the materials most commonly used for panes. Impact of different types of light sources. Humidity buffering capacity and rate. Inside/outside exchanges and leakage. Penetration and deposition of airborne particles. Advantages and disadvantages of airtight and non-airtight showcases in view of protection against dust, corrosive self-outgassing of VOC and microbiological infection and growth. A proposal is made to indicate all of the case characteristics, and their response to the ambient, with appropriate indexes, which represent the level of quality in view of the specific problems of the user. A quantitative evaluation of each index quality level is also discussed.