2 · Systems Thinking

The mechanical approach treats a building as an assembly of components: a structure, a mechanical system, an electrical system, a plumbing system. Each component is optimised for its own function, and the components meet at interfaces.

This approach is familiar, teachable and produces predictable results. It is also deeply limiting, because it cannot capture the synergies that arise when systems work together as a whole.

The systems approach treats the building as a node in a larger web of flows — energy, water, nutrients, information. Components are optimised not in isolation but in relation to each other and to the surrounding environment. The goal is not maximum performance of each part but optimal performance of the whole, over time.

Here is the chain that one decision sets off.

A decision about building orientation affects heating load, which affects the sizing of thermal mass, which affects the amount of solar glazing needed, which affects daylighting and visual comfort — and also the cooling load in summer, which affects the ventilation strategy, which affects where the openings go, which affects the structure.

And here is the other kind of chain. The water you harvest from your roof becomes the water that washes you, which becomes the water that grows plants in a treatment planter, which becomes the water that flushes a toilet, which becomes the water that feeds a garden, which becomes food that feeds you.

Systems thinking means designing energy, water, waste, food and structure as one system rather than five.

It requires holding more variables in mind at once, and resisting the temptation to optimise any single system at the expense of the whole.

It consistently produces better outcomes: lower costs, greater resilience, richer living environments, and genuine ecological benefit.

The cost saving deserves particular attention, because it is the least intuitive result. A building that needs almost no heating needs almost no heating system. The money saved on the furnace, the ductwork, the gas line and forty years of fuel is not a small offset against the thermal mass — very often it exceeds it. Passive design is frequently cheaper in total than the conventional alternative, and it is always cheaper to run. That is a systems result. You cannot see it by pricing the wall.

Once you can see it, you see it everywhere: a house with beautiful south glazing and no thermal mass, so it overheats by noon and is cold by midnight. A superbly insulated building with a ventilation system that runs constantly to compensate. A rainwater system sized without reference to the roof. Each component is correct. The building does not work.

This is the most useful single habit this course can give you: when something in a building is not working, look at the relationship, not the component.