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Wary of Waning Power Supplies, Eco-Minded Architects Build a Better Box
Source: Copyright 2008, Washington Post
Date: April 5, 2008
Byline: Katherine Salant
Original URL
Dennis Meadows has long argued that the world's resources are limited and its
environment stressed.
In the 1972 bestseller "Limits to Growth," he was part of a team that concluded
that the world would exceed its resource base in the first half of the 21st
century. In subsequent updates, they have said that the world's growing
population has already outstripped its resources and that we are now
collectively consuming our planetary seed corn.
Meadows is beginning plans for a major renovation of his house in New Hampshire.
High on his list is the need for a backup power source.
This is not a priority for most people planning a new house or a major
renovation. Despite having endured power losses caused by weather or man-made
grid glitches, most people regard outages as random and uncommon.
Meadows, though, said he thinks power losses will occur more frequently as the
sources of the fossil fuels that power our grid become less reliable.
Within 10 to 20 years, he predicted, prices for electricity and home heating
could be four times what they are today because of fuel scarcity. Or you could
flip the switch and nothing would happen because the local utility's fuel source
is in a foreign country that has become an unreliable supplier.
Other reasons for the scarcity could be of our own doing. Although our thirst
for electricity grows undiminished, many states no longer allow new construction
of coal-generating plants.
Renewable energy sources including solar and wind will eventually be important
producers of our electricity, but the transition will not be seamless, Meadows
said.
So what kind of backup system is appropriate?
Although high-tech gizmos can be enticing, homeowners should first seek to
reduce energy loads. That way there's less to replace during a power loss, said
David Foley, a Maine-based architect who is working with Meadows.
In Maine and New Hampshire, where the winter temperatures can reach 15 degrees
below zero, the best way to cut heating energy is to "build a better box" with
materials that are readily available, Foley said. Homeowners in his area can cut
their heating requirements in a new house by at least 50 percent by doubling the
amount of insulation that would normally be used, installing windows with three
panes and conscientiously plugging air leaks.
The only observable difference is the exterior walls, which can be as thick as
12 inches.
In a renovation, these modifications can often be retrofitted. Either way, the
house will be so airtight that mechanical ventilation must be added. However,
heating equipment can be much smaller.
Even more insulation can reduce heating requirements to the point that the heat
given off by the building's occupants, appliances and lighting, plus the passive
solar heat streaming in through south-facing windows, is sufficient for the
entire house. This approach, called the passive house, was pioneered in Germany
in 1990. About 9,000 such buildings have been built in Europe.
The first passive house in the United States was built in Urbana, Ill., in 2003
by Katrin Klingenberg, an architect and a professor at the University of
Illinois. She said she can heat her 1,200-square-foot house with 10 100-watt
light bulbs.
To accomplish this in Urbana, where the temperature can fall below zero during
the winter and rise above 100 during the summer, her walls are 16 inches thick,
the insulation in her attic is 16 inches thick, the windows have three panes,
and the underside of her concrete floor slab is insulated to a depth of 14
inches. (There is no basement.) Her house is 90 percent more energy-efficient
than a conventionally built house in Urbana.
In Florida, which has a relatively benign climate, a passive house would be far
easier to build, said Danny Parker, a senior research building scientist at the
Florida Solar Energy Center in Cocoa.
In Florida, unlike in the Midwest and the Northeast, you save energy with a
building that keeps the heat outside. The change in wall thickness from adding
insulation would be barely noticeable -- it's about 1 1/2 inch. White roof tiles
and white siding would reflect heat from the house.
Other modifications include dual-paned windows with an energy-efficient coating,
a three-foot overhang to shade the walls below, added tightness to prevent hot,
humid air from leaking in, and carefully sealed air-conditioning ducts that are
within the cooled space. These steps would reduce energy needs by 72 percent
compared with a conventional house. Tile floors would reduce cooling needs even
further.
This strategy is so effective that a house that incorporates them would be
cooler without air conditioning than a conventionally built house with the air
conditioning running, Parker said.
Once you've reduced the energy loads, what about the backup system?
The most cost-effective choice is a gas or propane generator, even though it
uses fossil fuels, all three building experts said. Foley, the Maine architect,
sizes one to provide enough power for "comfortable camping" -- heat, well pump,
ventilation, refrigerator and a few lights.
To get this level of power using alternative energy -- a sun-powered
photovoltaic system and batteries that provide power at night -- is
prohibitively costly unless the house is quite small, he said.
In Florida, a photovoltaic system and batteries would be more feasible because
"comfortable camping" there requires less energy than it does in Maine, Parker
said.
For Additional Information:
(may become dated as article ages)
For more information on the Passive House, see http://www.e-colab.org and
http://www.passivehouse.us.
5/4/2008
- Wary of Waning Power Supplies, Eco-Minded Architects Build a Better Box,
Washington Post
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