Reduction of window design risk in houses: Testing a simple calculation method

A previous paper by the author showed that the selection of inappropriate combinations of wall and window designs by the 'passive solar' designer could lead to a seasonal auxiliary energy penalty instead of the expected advantage. A simple method was proposed whereby a designer could calculate a 'critical house temperature difference' which would enable the average efficacy of different combinations of window and wll designs for different orientations to be evaluated over a heating season and so reduce the risk of incurring an energy penalty. The proposed method has now been tested using DEMON, a program derived from BREDEM 8, and shown to be effective for the cases used. This paper describes the testing of the proposed calculation method.