Systems Thinking in Residential Design

About this course.

A home performs best when it is designed as one integrated system rather than a collection of separate parts, because those parts are not independent. The building fabric, the orientation, the glazing, the insulation, the airtightness, the ventilation, the heating and cooling, the hot water and any renewable energy all interact, so a decision made in one area changes what the others need to do. Designing them separately — or in sequence, each chosen by a different trade or consultant without reference to the rest — misses those interactions, and usually produces a home that is less comfortable and more expensive to run than the sum of its parts should allow. Systems thinking is simply the habit of keeping the whole picture in view while making each individual choice.

The clearest example of the interaction is the relationship between the building fabric and the heating and cooling system. If the fabric — the insulation, glazing, orientation and airtightness — is improved so the home loses and gains less heat, then the amount of heating and cooling the home needs falls. A smaller load means a smaller, cheaper heating and cooling system, which in turn costs less to buy, less to run and less to maintain. Conversely, if the fabric is poor, the mechanical system has to be larger and works harder for the life of the building to compensate. So a decision about insulation is also, indirectly, a decision about the size and cost of the air conditioner. Treating the two separately — specifying a standard system regardless of the fabric — throws away the saving that better fabric could have unlocked.