Lazy overglazing is causing expensive problems Glaze for daylight, privacy and views

11 April 2022 by Jason Quinn

What is it with glass? Buildings in Australia and New Zealand tend to be over-glazed. Is it because huge windows look good in the renders and are a quick go-to for lazy architects? 

Glazing is best used to frame views. Think of windows as picture frames, not an alternative material for a wall. Glazing needs to be designed with three things in mind: letting daylight in, providing privacy where desirable and allowing for the optimal amount of heating.

Floor-to-ceiling windows are useless for increasing views—unless your client makes a point of lying on the floor beside the window to look outside. Anything glass below waist height is wasted from a view point of view (except if you are designing for a short-legged dog).

A recent Initial Design report we completed indicated a significant overheating problem. It was resolved by reducing glazing by 11 square metres (glazing which costs about $2K/m2). So the client saved more than $20K from that initial consultation. 

The other solution to overheating is to design in external shading. (External is key here, because curtains don’t help much. By the time they block light, the heat is already inside the thermal envelope.) Some clients are happy with this compromise, but it’s another cost and not everyone wants to sit in the dim in the middle of a summer’s day.

If architects design a floor plan with the interiors in mind, they can accurately calculate the optimum placement of windows for view by thinking about where people will sit, stand and walk and what lies outside that is good to look at. Combine that with an excellent understanding of the arcs of summer and winter sun and how to use eaves to bring as much sunlight into the house during the cold months and exclude it over summer.

Comments 1

  1. Thanks for another article. Generally good info about sensible use of glass but I tend to disagree with your opinion that glass to floor level ‘is useless’. In many situations it provides a welcome and calming connection to the outdoors. And yes, sometimes lying in the winter sun on the floor by the window can be great for the soul (and no I am not a dog ;-).
    Glass to floor (in my opinion) can make for a more comfortable home.

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