Probabilistic model of heat loss through the building envelope.

A model for the application of probabilistic methods is the estimation of heat loss caused by convection and heat conduction through the material is developed. Temperature difference (delta T) between inside and outside of a building, air change rate (ACH) and coefficient of thermal transmittance (U-value) of the building structure are treated as random variables. The mean value and standard deviation of heat loss are estimated for different parameters of distribution for temperature difference, air change rate and thermal transmittance. The interaction between the above three quantities is described for different cases of tight and leaky envelopes by assuming certain degree of correlation between the random variables.