Take a look at any housing site where multiple dwellings are being constructed and it’s likely that a majority of the properties include features such as bay windows and dormer windows. Such traditional features remain a common part of modern house design.
While there’s nothing inherently wrong with that, they introduce complexity into designs where retaining simplicity would be easier to both detail and construct.
Energy efficiency and occupant comfort are achieved in part through installing the right amount of insulation – and installing it well.
Making sure of the continuity of insulation and airtightness layers is necessary to eliminate weak spots where heat loss and air leakage would otherwise occur. It stands to reason, then, that the easier it is to install those layers, the better the end result is likely to be.
Ideally, that means keeping design simple, minimising complicated details and changes of geometry. The finished build is more likely to achieve the performance expected of it, and the homeowner enjoys more comfort and lower energy bills.
Installing rooflights and roof windows is a means of providing light to the internal space without compromising simplicity. As a single unit, they offer a reliable declared performance, easier installation, and relatively straightforward detailing in terms of getting the best out of the building envelope.
Dormer windows, by contrast, are inherently complicated. They require more improvisation and far more attention to detail during installation. Their relatively thin structural build-up makes it hard to install the necessary thickness of insulation to achieve low U-values to match the rest of the building.
Undoubtedly, dormer windows can open up additional space in a loft or attic room. A well installed roof window, on the hand, can make that space more comfortable – and provide more natural light at the same time.