By Stacy Hunt
Imagine a car that had an engine designed to go up to speeds of 120 miles per hour, but was equipped with tires that were designed to only go 60 miles per hour. Now imagine the disasters that might occur if the driver was a lead-foot who liked to cruise at 80 mph.
Eventually the incompatibilities would lead to disaster. Case closed.
Luckily most auto makers reduce such accidents using basic principles of systems engineering – a practice that takes a complex engineering process (in this case, manufacturing a car); focuses the process on the end goal of creating a product that is designed to perform effectively as a whole; and then breaks down each engineering and construction task to support that end performance goal.
It seems simple in theory, but in reality, systems engineering is rarely applied to the construction of homes. So the example of the ill-designed car actually holds true in reality with many homes –the cause of many significant building failures. Homes are simply not designed and built as whole products intended to perform as a whole system. Usually, rough plans are drawn up or purchased, and subcontractors are left to their own devices to come up with plans for each subsystem (i.e., HVAC, plumbing).
The lack of systems engineering is well-illustrated in the performance of HVAC systems. Say that very efficient, effective heating and cooling equipment is purchased and installed in the home. But the duct system is run willy-nilly throughout the home, using unsealed, very long and poorly located duct runs and ill-placed registers. The result is a home that's inefficient and uncomfortable — and often unhealthy for the occupants.
Systems engineering as applied to the design of homes assumes an end performance goal. For the sake of discussion, let's assume that there is a series of performance goals set for the home, such as those posed by the U.S. Green Building Council's LEED for Homes Program. Each system in the home is then "deconstructed" to meet the specific criteria of these end-performance goals, and put back together, taking into account the interactions of all of the systems upon the whole. Each system is optimized looking at the other systems in the home, so that they all play well together and create a home that's as efficient and effective as possible — as a whole product instead of a bunch of systems living together as strange bedfellows.
A good example is the U.S. Department of Housing and Urban Development's Partnership for Advancing Technology in Housing (PATH) Concept Home, built in 2007 in Omaha, Neb. The home has been engineered to achieve a number of performance goals – including LEED for Homes, EPA's Energy Star and Environments for Living. For example, the systems in the home have been designed to achieve a specific principle set out by the PATH Program: Integrated Functions, which focuses to combine systems to increase efficiency, reduce equipment needs and promote multi-functional designs.
An example of how integrated functions are employed in the PATH Concept Home is whole-house mechanical ventilation incorporated into the heating and cooling system. From the foundation to the finishes, the PATH Concept Home considers the interaction of each system with every other and ensures effective performance of the home as a whole house.
Systems engineering for cars makes sense; traveling on our roads is probably one of the most dangerous activities people undertake every day. The performance of their cars is critical in maintaining their safety. A home that is designed and built with a thoughtful systems-engineering approach also makes sense to ensure the safety, health, durability, comfort and energy efficiency of the biggest purchase your customers will ever make.
Stacy Hunt is a consultant and freelance writer who specializes in building science and green building. She is the former business manager of BuildIQ.
| 
){kind=logo}
