Local architect Charles McLaren saw fit to weigh in on the energy performance of log homes last week.
He assures us that his opinions carry punch because his first degree was in physics. On the basis of this credential, he took me to task over my contention that building codes do not adequately anticipate the real energy performance of solid timber homes.
For what it is worth, my science degree (master of forestry science) taught me to be cautious about what we think we know. Forestry requires observation of nature. It reinforces awareness that there can be a big difference between predictions from theories, formulae, modeling, and laboratory testing – and what is observed in the real world.
The fact is that the energy provisions of building codes – when applied to solid timber buildings -are based on modeling and laboratory work. They project from laboratory experience and limited-case studies into the real world – they are not based on out-in-the-environment data.
A survey of the literature shows that the energy use of truly comparable structures – situated outdoors, with all variables other than wall construction held constant – has never been measured and compared.
Thus we have a disparity between what is predicted and what people experience. People who live in well-built log homes report that their homes are more comfortable and less costly than Mr. McLaren’s application of the Law of Thermodynamics would predict. Indeed, more comfortable than regular homes.
By conventional measures, my home with 10” timbers is equivalent to a 2×4 stud wall. This is nutty. But even though a thousand years of timber home dwellers know otherwise, the data to prove it are lacking. There is indeed something else beyond presumed R values (R1.4/inch of timber) going on with timber homes.
So kudos to the Yukon government for their fair-minded policy that exempts solid timber from an inadequately informed energy performance code. And kudos to the Southern Alberta Institute of Technology (SAIT) for undertaking a badly needed study that will at last provide valid comparative data.
Over a full year, SAIT will measure the constant energy consumption of a set of buildings that are sited in the same way and are identical in every respect except for type of wall construction. Several thicknesses of timber homes and several types of stud-wall homes will be tested and monitored. The comparative effectiveness of different energy modeling computer programs will be evaluated as well.
Mr. McLaren calls log buildings “energy hogs” and “unicorns,” but the data proving his opinion do not yet exist. Saying it’s so doesn’t make it so.
We are all entitled to our own opinion, but not to our own facts. The SAIT real-world study will give the facts we need to understand how timber homes compare to conventional homes.