There are new provisions for energy efficiency coming into effect this December in the BC Building Code. They place an emphasis on air tightness and insulation. There will be an increase in minimal insulation values in attics, basements and walls. As well new code (section 9.36) will require a higher value of air tightness compared to present values.
This focus on energy efficiency adds to the relevance of ‘House as a System’ ideas and concepts. Efficiency measures that, in the past, weren’t cost effective or would take too long to realize a return on investment are now making more and more fiscal sense. So, yes, these concepts add to the initial cost of building new or substantially renovating your house. However, not only are increased efficiencies realized, but comfort and health benefits increase. Couple that with rising energy costs and you may be back in black sooner than you think.
“If you are going to build a house tight then you must have the ability to control and condition the air inside…”
The House as a System system consists of four major components which all must work as a whole. They are:
- building envelope- that which separates the external environment from the internal one
- the mechanic system- the heating cooling and venting of a house
- the exterior environment-climate, seasonal changes, house exposure, orientation and location all have an effect
- the occupants-a big variable on the inside. Basically, we boil things when cooking, bring wet things inside with us, have plants, dogs, cats or iguanas, have 30 friends over (then don’t), use steam showers, baths, hot tubs and indoor pools. They all generate water vapor.
These components have their own variables that can push and pull on the system. It must be able to adapt to these variations brought on by weather, indoor and outdoor temperature, humidity and pressure. I find that the area deserving of the most scrutiny is the envelope. Once the basic design of the envelope is determined, including: locations of air and vapor barriers, types of windows doors and skylights, as well as amount and type of insulation, then the heating type and size can be determined. This is done with the help of computer programs that model how they will function in any given envelope; too big is inefficient and too small is insufficient. Once the type of heating system is chosen it is fairly simple to size it correctly. The complexity lies in the endless details of the building envelope. Not only must they function flawlessly for hopefully hundreds of years (unlike the leaky-condos we all remember from the 80’s) but they must also be aesthetically pleasing as well. Smart AND beautiful, just like my wife (who is typing this and wants everyone to know it was not she who added that sentence…). And not one of these details can fail. In our upcoming Adera Project we are going to build the tightest house we have ever built, and we are going to focus our blogging on that project as an example and reference it in real time. We shall eventually be looking at:
- foundations-below grade exterior walls and floor
- above grade exterior walls
- windows and doors
- roofs and attics
- air, vapor, water and thermal barriers
Learn more about Green Construction — Join us at 10:00am the last Saturday of every month starting July 26th for a FREE home-tour on an active green-certified building site at 1607 West 57th Avenue, Vancouver. You’ll get an informal look at some of the latest concepts, methods and materials used in sustainable, healthy house design in Vancouver and a better understanding of how to build green. See you there!