This paper examines the impact on domestic background air infiltration of replacing ‘old windows’ with modern double-glazed and draught sealed windows, both with and without controllable ventilation (e.g. trickle ventilators). Methods of estimating the change in infiltration rate produced by such a window replacement are reviewed. A simple model has been developed which, using laboratory measurements of window air permeability, predicts the reduction in infiltration that can be expected when a given number of windows are replaced in a dwelling.
Experimental U-values based on measured heat flows through the walls of some houses have been found to be significantly higher than predicted by conventional calculation procedures. The work was carried out in ordinary occupied houses, and included measurements on party, internal and external walls. There are a number of possible reasons for the differences including thermal bridging, high thermal conductivities and excessive air movement in the wall cavities and behind plasterboard dry lining.
The Canadian Commission on Building and Fire Codes, senior committee in a national consensus structure dedicated to the writing of model codes under the auspices of the National Research Council of Canada, is preparing a new Canadian energy efficiency code for new buildings, to replace the Measures for Energy Conservation in New Buildings, published in 1978 and 1983.
Draughts due to air inlets are one of the problems to be solved for improving the global performance of mechanical ventilation systems. The CSTB full scale test cell "EREDIS" has been used to quantify draughts risks due to air inlets by measuring air temperatures and velocities with known boundaries of wall temperatures and fresh air. The results allow to improve the design of these inlets and to give advices for a better use in residential buildings. Works are now going on for comparing the experimental results to the ones calculated with a CFD code.
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