According to the Green Building Advisor, “the truth is
that there seems to be a fair amount of agreement that it’s a house that is
built better than code but that does not necessarily meet the requirements of
Passivhaus, net zero, LEED, or other particulary stringent building standard.” Here are some discussion group notes as to
best practices for the Pretty Good House Movement from Michael Maines at the
Green Building Advisor.com ….
·
Support the local economy. That means
building with local labor, with locally available and/or produced materials, as
much as possible.
·
Be commissioned following construction, and
be monitored on an ongoing basis. If you don’t know, and to me it’s a strange
use of the word, commissioning means testing how the house performs after it’s
built. There was some discussion about how effective an energy-use “dashboard”
can be. (“What gets measured gets improved.”)
·
Have operating costs that are minimal or
reasonable.
·
Have 10-20-40-60 insulation. Hopefully these
numbers are obvious: they represent a “pretty good” level of insulation in a
cold climate for sub-slab, foundation walls, framed walls, and roof or ceiling,
respectively.
·
Measure 1000-1500-1750-1875. These number are
probably not as obvious; they represent an allotment of square feet of living
space for 1, 2, 3, and 4+ inhabitants, respectively. It could be less — the
national average is much more — but as a group we thought this was… pretty
good.
What is in, what is out?
The discussion group came up with a list of what is in
versus what is out of a pretty good house. What's in:
·
Superinsulation.
·
4 inches of rigid foam under the basement
slab.
·
A service core for plumbing and wiring (à la
Tedd Benson’s Bensonwood concept, also a feature of A Pattern Language
(Alexandar, et. al.): keep services out of exterior walls, grouped for easy
upgrades in the future.
·
Energy modeling (performed during the design
process).
·
Adaptability/durability/recyclability. For
more on this topic, see Alex Wilson’s blog, “Ensure Durability and Reuse
Existing Buildings.”
·
An air leakage rate of no more than 2 ach50.
Not exactly Passivhaus, but… pretty good.
·
Good design. I was surprised it took so long
for someone to mention this. A good house has to look good and feel good, not
just function well.
·
An owners’ manual. I know that Michael
Chandler has written about this. You get an owners’ manual with your car, DVD
player, and electric toothbrush. Shouldn’t the biggest, most expensive, most
complicated thing you own have an owners’ manual too?
·
Universal Design. Our population is getting
older, and people are realizing that having a disability does not mean one's
lifestyle needs to be limited. For the most part, Universal Design is smart
design.
·
Comfort. Recently I was at Chris Corson’s
Passivhaus project on a cold day. There were no drafts, no cold spots in front
of windows, and only a single Mr. Slim heat pump for the whole house. It was
comfortable. I’ve been in $20 million dollar houses that were not comfortable
(and probably insulated with fiberglass batts).
·
Keep it simple
·
What's out:
·
Toxic/unhealthy materials.
·
Too much embodied energy. Spray foam is a
great insulator, but it comes at a cost. Vinylsiding is cheap and (somewhat)
effective, but it comes at a cost. Bamboo flooring comes at a (transportation)
cost, and having installed quite a bit of it, I don’t think it’s all that
great….
·
Diminished returns. The idea of the Pretty
Good House is to find the sweet spot between expenditures and gains. When is
enough insulation enough?
·
Complexity of structure. With modern living
space “needs” and small lots come oversize houses. One way to reduce the apparent
scale of the house is to chop up the roof with dormers, pepper the walls with
bumpouts, and otherwise create places for ice dams, air leaks and extra
construction labor and materials.
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