Buildings by their nature almost always strive to provide a stable and comfortable environment for human occupation. Whilst there will be some variations in expectation – a swimming pool is not an office – we will generally work to keep buildings warmer than the external temperature in winter, and cooler in summer.
Heating a building in the winter, using active systems, is energy intensive and rightly the target of much environmental design effort. It takes a lot of energy to keep an interior at +20C when the exterior is -10C. We recognise this is particularly the case with buildings such as houses and apartments, where occupancy is low and consequently the internal heat gains are low (compared to an office for instance). Free passive gains can be made by considered use of glazing and shadings, which are selected to give maximum benefit in the winter months. Ultimately it will be fundamental though to ensure the opaque envelope of the building works to a high level, retaining warmth within the building rather than releasing it wastefully to the exterior. The envelope will normally be where the structural systems, such as framing or load bearing walls, come together with the skin of the building. This makes our understanding of how construction systems work together crucial , to ensure high standards of airtightness and effective and continuous insulation.
“Very often money is wasted installing thick insulation in walls and roofs without ensuring the detailing will make the insulation effective. Badly fitted rigid foam boards are a classic example, where thermal bypass is often a real problem. Rather than relying on thermal imaging at the end, it is better to specify a realistic and buildable system.”