Using the rules of thermophysics, aerodynamics and mathematics, it was analysed how the constructional and technological factors of the building influence the parameters of effective insulating rate and ventilation. It was composed the formula for calculating the effective coefficient of the heat transmission of the external barrier. This formula integrally evaluates the heat balance of the building, incondensable water vapour condition, constructional and technological factors. Using the composed formula, it was established that after increasing the amount of animal total heat flow to the ground area unit from 90 to 150 W/m(2), it would be rational to reduce the coefficient of the heat transmission from 5.0 to 2.3 W/(m(2) K). After reducing the coefficient of the heat transmission, the indoor air temperature during the cold period increases about 7degreesC. It was composed the formula for calculating the parameters of cowshed ventilation system according to outside air temperature. According to calculations, when the outside air temperature is dropping from 20 to -20 degreesC, it would be rational to reduce 85% of the vent area. (C) 2004 Elsevier B.V. All rights reserved.