| Like many of the concepts in Green Building, Life Cycle analysis is
conceptually simple, but difficult when it comes down to details. As
the name indicates, the idea is to look at the impact of a decision over
the amount of time that it will exist for. For environmental impact, it
means considering not just the impact of creating the material, but the
impact it has during its lifetime and then the impact it has when it is
disposed of. There is also a life cycle analysis looking at costs:
in addition to the purchase price, we must add the costs of operation and
maintenance.
Life cycle analysis for environmental impact is a difficult task
because you don't really know up front how long a material will
last. In addition, with new manufacturing techniques coming out,
corporations have been slowing lowering their environmental impact.
In the meantime, debates about the relative impact of various choices will
rage on and designers and consumers will be left using their instinct and
personal preference to make the best choice possible. Since the
greatest impact decision one makes is how much space to build, one is
better off spending time doing a good job there while avoiding the really
bad materials than trying to determine the difference between two
acceptable materials.
Cost is always a major decision maker for almost everyone, and
typically is determined only by the up front cost. In many cases
this is a big mistake in the long run, especially if you will live in the
house for a long time (and sometime even when you won't). Admittedly
everyone has a budget, and if a a loan is involved in purchase of the
building or remodel, the bank will enforce a budget. In this case
also, building small is the biggest impact one can have. Although
the cost per square foot often goes up with smaller buildings, its because
the owners have money left over to put in more quality materials.
As an example, consider low cost sheet flooring at about $4/sq ft
versus hardwood or tile at $10 to $12/sq ft. Depending on your
pattern of usage, the more expensive products, costing about 3 times more
can last 5 times longer while also increasing the resale value of your
home.
Another example is to compare a standard washing machine with a low
water use model. The standard machine at $380 uses about $217/yr in
energy for a ten year cost of $2550 while a low water use one is about
twice as expensive at $700, but uses only $111/yr in energy, for a ten
year total $1810, or a saving of $740. (These number were taken from the
energy guide stickers on machines and were chosen in an attempt at a fair
comparison: they aren't extreme numbers. Every year new machines are
introduced and prices and energy use changes so remember that actual
mileage will vary!). Note also that the new efficient machine often
use less detergent and are gentler on your clothes resulting in added
benefits.
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