Planning principles for airtightness

In planning a building, the air seal strategy needs to be developed early on. Some aspects of this in keywords are:

Select the simplest possible shape for the heat transferring envelope of the building, with little variation in material.
Define the position of the windproof and airtight layer, with unheated areas such as the basement clearly separated.
Minimize the length of junctions, make surfaces as homogeneous as possible.
Choose simple structures, avoid penetrations.
Reduce penetrations for building services; if appropriate, plan a service layer.
Define materials and installing techniques that seal areas and joints.
Precise planning of details and coordination with tradesmen are vital.

Rule of thumb: The more joints between different building elements, the more potential leaks in the airtight layer!