Infiltration and heat transmission, Tjyvdrag och transmission.

Notes dangers of incomplete theoretical models distorting technical progress. Cites as example determination of U-value in estimating energy losses through building envelope. Concentrates on considerable energy loss caused by air infiltration, in addition to heat transmission. A step towards a better understanding of total energy flow through building envelope is a method of calculating air leakage. Describes calculation results for a house which show that air tightness is an important property of the building envelope which cannot be neglected.