Windows In Buildings - Brief Article

Architectural Review, The, June, 2001 by Michael Wigginton

By N. Abodahad, J. Kubie, Tariq Muneer. Oxford: Architectural Press. 2000. [pound]50

This is a genuinely useful review of the performance of windows, which pulls no punches in relation to physics and mathematics.

The book deals with performance in five main chapters, preceded by an introduction and 17 pages on the Microsoft Excel computer program (a copy of which is provided with the book), and concluding with sunlight and daylight data. The chapters on thermal transmission and solar heat, taken together, deal properly with what is often oversimplified, and correctly make the case for the effective U-value as an appropriate thermal performance indicator (in which solar gain can be used to compensate for conductive loss). Diagrams such as that describing the intricacies of heat loss through the edge of a double-glazing unit, with its five separate material components, are exemplary.

The following chapter on daylighting, too, contains a fairly full coverage of the usual material, albeit with little mention of colour.

The chapter on acoustics is the shortest and the weakest. It is surprising that conventional ways of providing sound attenuation by cavities is not referred to: subsequent editions of the book could usefully expand the treatment of this aspect of window design.

The final main chapter, on life cycle impact, is very welcome.

All in all, this is a useful and valuable book. It varies from the mathematically bewildering (to most architects, I suspect) to the blindingly obvious (the daylight and view aspects of a Venetian blind, for example). The bibliography and references are thorough and full, as one would expect from such authors, and the extensive reference to their own work is surely more a result of their own scholarship than self-regarding. It is disappointing that the authors do not extend their treatment into giving guidance and recommendations for design (which they perhaps might have felt was beyond their self-set brief), and their reference to new technologies is scant, and sometimes wrong (for example in relation to silica aerogel and electrochromism). However, they have elected to produce a thorough, uncompromising, if dry, review of performance, which will serve most designers well, particularly those with the ability and patience to grapple with the physics. As such it is particularly commendable to postgraduate an d research students.