Design Principle #3: Insulation

Before I got side-tracked by our postal and electrical adventures in Neverland (From off te grid to off te radar), I was working my way through our 7 design principles for this project starting with solar gain and thermal mass. As June and I explain in our short video, Introduction to Passive Solar Design, it is essential that insulation work in conjunction with sun-facing (toward the equator whichever hemisphere you’re in) glazing and adequate mass inside the building envelope.

Not rates envelope, building envelope!

If you are familiar with the greenhouse effect you may see a parallel here. Ultraviolet light comes streaming through our windows in the same way it enters Earth’s atmosphere. When it strikes the ground surface of the planet – or the mass inside our home – some of that UV light is transformed in infrared light, i.e. HEAT. We all know that heat rises, and in the case of the Earth it is the carbon dioxide, water vapor, methane and other greenhouse gases that ‘hold’ the heat in and make the planet habitable. Good on ya, CO2!

But the problem we all face now is that too much CO2 and other greenhouse gases are essentially over-insulating this planet and causing a laundry list of potential less-than-desirable consequences. That’s why the proactive and responsible governments of the world are in Cancun, Mexico sorting it all out for us. Good on ya, politicians!

While the results of that meeting are likely to be nothing more than hot air, it is precisely hot air that I am hoping to hold within our home. I wish insulating the attic was as easy as filling it with carbon dioxide. Unfortunately, we have to settle for Pink Batts.

There are pros and cons to each choice of insulation depending on whose advice you seek, and I’ll try to write about that in the future. But today’s lesson is ‘location, location, location.’ Getting the most savings for your insulation investment (being eco-thrifty) is about identifying the low-hanging fruit and picking it first. In the case of insulation, it just so happens that the low-hanging fruit is up high and the high-hanging fruit is down low. In other words, insulate your attic first, your walls second, and your floor last. In this case physics and economics work hand-in-hand.

Relative heat loss through roof, walls and floor of an uninsulated home.

For our do-up down-under, we are insulating the entire attic, all external walls where Gib board has been removed, and under the floor in the northern 2/3 of the house? Why only the northern 2/3? Find out in a future post.

Peace, Estwing

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