The super insulated house: How it's done and why.

Today, I have a special guest post.I have asked Gilles to explain the insulation of our house for those that are more interested in the technical details.  I am very impressed with the setup but could never do it justice. So here is Gilles' post:

Our house will be super insulated, R45+ for the walls, R85+ for the attic. More than twice the standard. I will accomplish these exceptional ratings with the double wall construction technique. Walls will have a profile of a sandwich: Standard 2" x 6" structural framing with fiberglass wool, 2" of foam, which also act as a thermal break. A 0.006 poly vapor barrier and a 2" x 4" interior structure filled with fiberglass wool and covered with regular panels of drywall. All plumbing and electricity will travel within that interior 2" x 4" structure therefore maintaining the vapor barrier intact to make sure the house is as airtight as it can be.

Obviously the main idea of a super insulated house is to save on energy cost. I like to say that I will be able to heat my house with my farts. It's barely a joke because in reality, the heat from human activity combined with the sun exposure will be enough to keep the place warm. The house is facing South and about 80% of the window surface is on the South wall. The rest of the windows are for cross ventilation. Needless to say such an airtight house has to be ventilated mechanically. To control the humidity level and to make sure that there is always a supply of fresh air. You know with the farts and all.

So the first question that comes to mind, is it worth it financially. In other words will the building cost offset the saving in energy bill. The short and quick answer is no. Not at today's electricity cost and not if you were to factor in the labor. Labor is somewhat intensive but not that complicated. The cost of materials is  relatively minor in the whole construction budget. But since I'm the one doing the labor, which I provide for free, it's a whole different calculation. Of course future energy cost is hard to factor in but common wisdom puts it at a premium. In short,  I would summarize the immediate benefit as one of comfort and as an investment in future options on energy. As far as resale value goes, forget about it. Nobody ask when they buy a home how it's insulated. They only have eyes for the granite counter tops and the stainless steel appliances.

Before I conclude this short presentation on the super insulation concept I would like to address a comment often heard that goes somewhat like this: Today's house are too well insulated, they can't breathe, blah, blah ,blah. Of course, such comments are from people that don't know what they are talking about. First of all, they confuse two different concepts, insulation and air tightness. While both techniques work together in the construction of a house, they are in practice two completely different things with different materials. They can both exist independently. Take a balloon for example, perfectly air tight but no insulation value. As well you could have a house with 4 feet thick walls but you could still feel the wind blowing while watching TV. In fact there are 3 aspects of a building envelope,  an exterior air barrier that keeps the cold air from penetrating the structure but lets the humidity escape, the insulation itself, and  a vapor barrier that prevent the moist warm air from escaping the house and creating condensation within the structure.The air barrier, usually a 0.006" polyethylene sealed with a special caulking at all seams and extremities. It has to be applied on the warm side on the structure. The dew point has to be on the outside of the vapor barrier. The efficiency of these 3 aspects is in the construction details. It's the work of a monk I tell you. That's where I'm at presently and it feels like I'm building a house within a house.

Thank you Gilles! Now we will all know how it is done!