Tuesday, December 3, 2013

Huge energy savings possible with passive houses

A rarely known fact – and one I love to repeat – is that our wonderful modern society uses energy in terribly inefficient ways.  Few of us know how much energy is wasted when you flip on a light switch, but the answer is delightfully instructive, and shocking.  Powering a light bulb from the power grid is only 1% efficient.  A staggering 99% percent of the energy is lost (to heat, specifically), lost at each step along the way: first at the power plant, then in transmission to your home, and then within the light bulb itself as it operates.  Think about it this way: 99% of the pollution emitted from the power plant causes harm to someone (or something, or someplace) without anything to show for it.

If you can tackle poor efficiency, which happens to span all aspects of energy usage, you stand to gain tremendously; doing more with less and, in the process, causing less damage to your surroundings.  The chart below shows the predicted energy usage of the Potwine passive house, compared to that of the typical home in Massachusetts.  The savings are enormous – over an 8 fold decrease in energy usage overall, much of it simply from increasing efficiency and smarter design.  The lion's share comes from reducing the heating load of the house and adding passive solar gain, but switching to LED lights and more efficient appliances also makes an impact.

We'll see if these predictions actually hold true.  If they do, then we've realized a practical, economical, and sacrifice-free way of reducing household energy consumption in the US.