Twelve factors are identified which may be used to describe control criteria for enclosed laboratory animals. The impact of this control can then be evaluated in terms of health and well-being of the animals and laboratory personnel, energy consumption and economics. A review of commonly cited standards and guidelines indicates that they are not explicit regarding required criteria for both the microenvironments and the macroenvironments. However, some data exist which would allow improvement of these standards and which could provide cost effective and energy efficient operations. To expedite these revisions, methods of promulgating voluntary standards are suggested.