Close

1st April 2015

Insulation: Windows

Insulating Dormer Windows

Dormers come in a large variety of shapes, sizes and materials and can be a difficult area to insulate, but if insulation is left out or is poorly detailed then the energy efficiency of the whole roof can be compromised. Here, information on the principles, risks, materials and methods for insulating dormer windows is provided.

Retro-fitting insulation to any existing building is not straightforward, even if it is of relatively recent construction. Considerable ingenuity and attention to detail is required to ensure that the insulation is installed effectively at every awkward junction and gap. Solutions will normally need to be individually designed for each situation and professional advice will often be required. The upgrading of dormer windows should wherever possible be undertaken in conjunction with general roof upgrading work.

 


Slim-Profile Double-Glazing

Improving the thermal performance of building envelopes is an important measure to make buildings energy efficient. Windows are often the building component which performs worst thermally, compared to the rest of the envelope. This is particularly the case for single-glazed windows. However, such windows are often located in historic buildings. The outright replacement in such buildings is, thereby, generally considered inappropriate, for conservation reasons. Nevertheless, there are various options to improve the thermal performance of such windows. Slim-profile double-glazing has generally a poorer thermal performance than conventional double-glazing, but performs thermally significantly better than single-glazing. Furthermore, such solutions can be fitted, due to their slimness, in most existing window sashes, thereby allowing for the retention of the existing window casements and/or sashes. This is an important conservation aspect, as the installation of double-glazing in historic buildings may be more acceptable in situations where it can be incorporated within the original joinery or within new joinery which matches the original.