Overall design

These are architectural and constructive measures that naturally provide a better indoor environment quality without or with much less energy use.

Examples are:

• Improving winter thermal comfort with thermal insulation, passive solar gains, thermal inertia, and controlled natural ventilation
• Improving summer thermal comfort with thermal insulation, solar protections, thermal inertia, and appropriate natural ventilation
• Ensuring indoor air quality by using low-emitting materials and controlled natural ventilation
• Providing controlled daylighting
• Protecting from outdoor noise with acoustical insulation, adjusting the reverberation time for a comfortable indoor acoustics

Passive means are often cheap, use very few or no energy, and are much less susceptible to break down than active means. However, they often depend on meteorological conditions and therefore cannot always fulfil the objectives. They should be adapted to the location and therefore need creativity and additional studies from the architect, and a design error may have dramatic consequences.

These allow reaching the objectives by mechanical actions, using energy for complementing the passive ways or even for compensating low building performance.

Examples are:

• Heating boilers and radiators for winter comfort
• Artificial cooling by air conditioning or radiant panels for summer comfort
• Mechanical ventilation
• Artificial lighting
• Actively diffusing background music or noise to cover the ambient noise.

Active ways, when appropriately designed, built and maintained, are perfectly adapted to the needs. The architect does not have to take much care of them, since these are designed and applied by specialised engineers according to known technology. Flexible and relatively independent on meteorological conditions, they allow correcting architectural errors. However, the required technology is often expensive, uses much energy and may break down. Furthermore active means require a higher maintenance input. The fact that they allow correcting architectural ‘errors’ can also be considered as a disadvantage.

Passive ways are preferred, but cannot always fulfil the comfort objectives. Therefore, the appropriate strategy is to use them as much as reasonably possible and to compensate for their insufficiencies with active systems, which will then be smaller. This strategy often allows more freedom in choosing the type and location of active system