A new simulator of the human head and animal bodies mimics moisture transpiration from eyes and skin and heat emission. The present invention used to demonstrate and quantify anti-fogging performance of goggles and apparel. Thin water permeable membranes are mounted onto a container containing a thermostatically controlled, heated and stirred reservoir of water as a simulation of the moisture source of the human eyes and skin. A light source and optical mesh patterns help illuminate water condensation on the inner lens of the goggles. The simulator results in a reliable and convenient demonstration and testing system for moisture condensation in goggle lenses, and heat and moisture apparel.