Systems Thinking: IT and buildings
by: Paul Kando
Who would buy a car from an auto-parts store to assemble at home? Yet when building or upgrading a house, most people think in terms of assembling parts. Like conventional builders, we focus on the price of building materials and labor, trying to minimize both in the name of "saving money". At the building site we tend to follow some routine. We may insulate the walls with R-19 fiberglass batts and the attic with R-30, because "that's code", or because we have always done it that way. We may add a plastic sheet, a thicker wall with more insulation and call it a tight house. Energy auditing such a house the other day, we found attractive features, good workmanship, but also severe moisture problems, complete with mold, musty smell and water-stained ceilings.
A friend I will call Jake comes to mind. He plans to build a passive house, doing the work himself, with the help of friends. He thinks and talks superinsulation, avoiding thermal bridges, airtightness, ventilation, good windows and so on. He asks a lot of questions about quantities and techniques. But Jake leaves out the most important element: knowing how to put such things together into a system, rather than an assembly of parts. He resists paying a passive house consultant for this know-how - "to save money". Yet, even before he starts construction, Jake is already on his way to waste money. He dug holes for the support pilings of his floor deck 8 feet apart, even though the size joists he will need to accommodate the right amount of floor insulation would allow him to place those pilings on 12 feet, even 16 feet on center, cutting their cost by up to half.
Jake complains he can't retire paying the rents he is paying. Yet he overlooks the fact that every systemic misstep he makes building his house will make living in it more expensive. Like most folks, Jake focuses on first cost, waving aside the total monthly cost of occupancy - mortgage + heating + taxes + insurance. He focuses on the cash he has, forgetting he could come out ahead borrowing the difference between what he thinks he can afford to pay and what it takes to build the best-performing house that will more than pay back the loan from ongoing savings in occupancy costs.
Perhaps systems thinking is counter-intuitive. Our whole society tends to think like Jake. Perhaps we were so trained, as our economy, our government, our houses, our consumption patterns all suggest. We are patsies for advertising and propaganda that bank on us not knowing how to think... certainly not in terms of how parts function together as systems. This is a very expensive way of thinking.
People desperate to reduce their heating bills often ask, should they replace the oil burning furnace with a wood stove or a heat pump? How much insulation should they add to the attic, the basement? I can't advise them in good conscience without looking at their house in detail, even though I know how furnaces, wood or pellet stoves, heat pumps and other heating devices work. And we all know that insulation keeps a house warmer and fewer air leaks will lose less heat. In short, we know how the parts work. But do we also know how heat, air and moisture interact in a particular heated house and the science it takes to understand what we must do to control each? Every house performs as a unique system. Is yours a perfect collection of good parts, but a faulty system?
Thanks to information technology - a newcomer to building arts - we know how to build houses that use 90% less heating energy (i.e. waste that much less) than a typical conventionally built house. We also know how to upgrade existing houses to perform nearly as well. The key is not just better components, nor even better techniques, but better systemic planning. Passive house construction is based on thorough computer-aided development of someone's dream-design into a working system, complete assembly instructions. This thorough planning takes place in advance of any work at the building site. The plan is followed to the letter during construction, not just in terms of what is being done, but how well. To make sure, the house is air-tightness tested several times during the process.
In an existing house a thorough energy audit is the first step of improving the performance of the building as a system. Based on the audit, systemic plans can be made, similar to building a passive house from scratch. How well the improved building will perform depends on the thoroughness of these initial analytical and planning steps.
With instructions anyone can assemble parts, but to build a safe car that runs well and uses no more fuel than necessary, one must also know how the parts interact as a system. How well a system performs - your house, your appliances, even your body - depends on applying systems knowledge. Jake and his friends can probably assemble a house. But he would do well to hire someone with the knowledge of how to make it into a working system. The alternative could be the most expensive thing in his new home - an "energy-mortgage" that's never paid off.