Most engineers call it "integrated design", but green systems installers like to use the word "holistic" because it rings of holistic therapy, holistic medicine and other natural alternatives that work just as well as their traditional counterparts. But what is it?

Holistic home design is the art and science of designing buildings as a whole. Rather than approaching construction as a set of unrelated steps, holistic design considers how the building will "exist" in the space available, with each of its component parts interacting and integrating with those around it.

Let's clarify this by an example. Traditional design walks through construction in a series of steps handled by different people; the only one who really sees the whole design is the architect. At an extremely crude level, the process goes something like this:

• Look at the houses in the area
• Make one that looks similar
• Include the right number of rooms
• Put windows in the walls
• Figure out where the pipes and electricity will run
• Work out where heaters won't be in the way
• Work out whether walkways will be obstructed and fix problems
• ...and so on

Of course, it's a lot more complicated than that – architects are extremely skillful and often remarkably talented individuals, and we have no intention of insulting their abilities! But traditional design is concerned with the functionality as humans see it, not as nature will affect it. It's all about light availability, attractive door placement, walkway sizes, obstructions, centerpieces and so on.

The end result is a home designed by an architect who hands off to a builder, who hands off to an HVAC contractor (for the heating, ventilation and air con systems). It's inefficient and relies on brute strength in the installed systems to overcome the inadequacies of the traditional, quick-fix design methodology.

Holistic design looks at the building as an entity existing in a natural space, so the process is more like this:

• Look at the houses in the area
• Make one that looks similar
• Include the right number of rooms
• Consider window placement for optimum lighting in the day
• Consider window placement for passive heating
• Consider window placement for views
• Consider thermal loss through larger windows
• Consider the thermal mass behind south-facing windows
• Consider the material used in walls which will be warmed by south-facing windows
• ...and so on

As you can see, integrated design looks at each individual element of the home's design and measures the benefits that can be gained against the effects that element will have on all the other parts of the overall home. The process is much more complicated and lengthy, requiring input from all sorts of professionals as well as the home owner to decide where compromises must be made.

But the end result is a home designed by an architect who worked hand-in-hand with the builder, the HVAC contractor and a variety of other specialists to come up with something better. It's efficient and relies on the intelligence built into the design to provide a home which is comfortable and pleasant to live in, year-round, with