SOLID WOOD
In 1981 the National Institute of Standards and Technology
constructed six test buildings in Gaithersburg, Maryland and tested
them for energy efficiency. Much to their surprise, Building 5, with
walls made of solid wood, was the most energy efficient. This was
attributed to "thermal inertia," a phenomenon where the solid wood
walls stored energy during the day, and released it during the night.
Actually the energy efficiency of solid wood is well known in the
Scandinavian countries where it is the prevalent method of building.
(Its long life is well known too. When interviewed during the 1994
Winter Olympics, a Lillehammer couple casually remarked that their
solid wood home had been built in 1406!)
THERMAL INERTIA
There is no logical reason to use a drop of fuel, or a watt of
energy, to heat or cool any home or building attached to the Earth.
Just below the surface, within reach of the average basement, is an
infinite reservoir of heat that never drops below 50 degrees F. The
night-day cycle is more than ample to raise that temperature into the
comfort zone, with a simple shift in Time. The use of daytime heat at night, and nighttime cool by day, is made possible by Thermal Inertia, and the engineered Lag-in-Time is a property of the thickness and Specific Heat of the solid wood walls.
HEAT PUMP HOUSE
The task of extracting useful heat from the geothermal reserve or
outside air is usually relegated to the electric Heat Pump. They have
been tacked onto homes by the millions - encouraged, even financed, by
the electric utilities. You have seen them - noisy, power-hungry,
CFC-filled, life-support machines - hanging off the side of an
obviously troubled building.
Our solution, in the Enertia® Building System, is to make the house itself
a heat pump, using the natural energy of rising solar-heated air to
extract and enhance the pool of geothermal energy just beneath the
building's floor. Simple, foolproof, no CFC's, no electric bill (see "Heat Pump House," Popular Science, June 1992, p.42).
THE ENVELOPE
Just how does a house, or office, or any ground-based structure
get turned into a natural energy machine? The secret is an air path, or
"Envelope" just inside the structure's solid wood skin. It is a heat
path on a sunny Winter day, a continuously recharging convection loop.
A heat source, and extra insulation for a cold Winter night. A
miniature biosphere, oxygenated by Sunspace plants. A fresh air-to-air
exchanger with walls that breathe. A buffer zone to noise, wind, and
outside pollution.
It is a ventilation path on the hot Summer day and on the
cooler Summer night, when it is open to the atmosphere. It is the
dehumidification system when its permeable outer wall is hit by the
sun. And always, an access channel to otherwise unreachable parts of
the house when it comes time to update, add new wires, cables, pipes,
or technology.
"FLOATING"
The Enertia® House works because the walls have the ability to
gain, hold, and release heat. They do double-duty as structure and
storage. Their thermal mass and thermal lag leads to "Floating," where
stored daytime energy cancels out night-time need. Floating can last
for days, keeping the house comfortable during periods of little or no
sun. Massive houses experience seasonal "Float" as well, and can coast
a month or longer when lightweight houses need artificial heating or
cooling. Enertia® Houses float right through heat waves and arctic
blasts that would endanger occupants of other buildings. ("Floating," Abstract: A Field study of the Effect of Wall Mass on the Heating and Cooling loads of Residential Buildings, Doug Burch, et. al. National Institute of Standards and Technology, 1982)
DELTA T
All architects and engineers work with the Heat Loss Equation.
Heat loss equals the temperature difference (Delta T) divided by
resistance (the familiar R factor). All modern attempts at energy
efficiency have focused on the "R" factor - i.e. more and more
insulation into a thicker wall. But reducing Delta T has the same effect - why not look at that? While insulation is necessary to increase "R" factor, Delta T can be reduced by natural means.
The Envelope presents an entirely different Delta T to the living space
than it would see if the house were single walled. Because of it, the
living space never "sees" conditions colder than the geothermal
temperature under the house! As the sunshine raises the Envelope
temperature in the closed Wintertime loop, Delta T goes to Zero, and "R
Value" is meaningless. At this point the Enertia® house is in
equilibrium and Heat Loss = 0.
RADIANT HEATING
The ultimate in heating and cooling, radiant walls and floors
are inherent in the Enertia® Building System. When your feet are warm,
you feel warm all over. It is efficient, dust free, even heat - more
healthy and invigorating because the air you breathe is cooler. On the
coldest Winter day, the Envelope keeps the North wall warm and you can
lean up against it. Try that in a conventional house.
RADIANT COOLING
The same thermal mass that acts as a heat source in winter
becomes a heat sink in summer, again enabling an energy-shift- in-time.
The envelope is opened to the outside for summer cooling - basement
windows for intake, rooftop windows for exhaust. Natural ventilation
carries off internal heat captured by the massive walls during the day.
The permeable walls allow humidity to migrate towards the outer surface
where it is evaporated by the sun. Because of the envelope, the house
is wrapped by the cool in-ground climate. (The House that Needs No Fuel, Architectural Designs, August, 1988, p.6)
A SYSTEM FOR BUILDING
Finally, we like our houses and offices in all shapes, forms,
finishes, colors, and styles. This is why Enertia® is more than houses
- it is a building System. While we have a catalog of
standard, proven plans - fully half our production is custom - working
from owner sketches and architects' plans. We feel that you should get
what you want in a house that you will live and work in and never want
to leave.
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