on an annual basis. We used local and non-toxic
materials, including beautiful clay plaster on
interior walls, whenever possible. Final interior
touches, an adobe tan stucco color coat and final
grading will be completed this summer.
Earth-Block Thermal Performance
Beats Adobe
Construction began in spring 2009, when
laborers used machines to form compressed-earth-block walls from soil excavated on site.
From the excavation site we created a pond.
Compressed earth blocks (CEBs) are similar
to adobe except they are machine-made instead of
sun-dried. CEBs come off the machine so precisely
formed that only a thin slurry of mud is used in the
joint, reducing the time it takes to put up the wall.
Many building sites in New Mexico have suitable
material for making blocks. In places where the
soil is good for a garden, it’s likely not good for
making a CEB (too much organic matter).
These blocks were used for the exterior walls
of the house and many of the interior walls as
well. With an interior mass wall, two sides are
exposed to the inside air, effectively doubling the
thermal performance over an insulated exterior
wall. The thermal conductivity of the CEB may
be higher than that of the less-dense adobe, but
is still much lower than stone or concrete; thus
more surface area of adobe is needed to absorb
the same amount of heat. An advantage of adobe
and CEB over concrete is that it transfers moisture as well as heat, important in our arid climate.
The sounds in the room also seem softer than
with concrete walls.
The CEBs and walls were made by Earth
Block Inc. ( earthblockinc.com) Founder Jim
Hallock has been building earth-block homes
for many years. He offers workshops and has
crews that come to your site to make blocks and
put up the walls. The cost in dollars is about the
same as other sustainable options, like insulated
concrete forms (ICFs), but ICFs contain the
a central feature of the home is the high-efficiency solar thermal system used for domestic water
and space heating. heated water is conveyed
through radiant tubes beneath the slab floor to
heat the space, and the mass floor stores the thermal energy.
JIM HALLOCK
laborers used machines to form compressed-earth-block walls from soil excavated on site.
these blocks were used for the exterior walls of
the house and many of the interior walls as well. a
pond was created from the excavation site.
with an interior mass wall, two sides are xposed to the inside air, effectively dou- bling the thermal performance over an insulated exterior wall.
concrete inside the insulation where it doesn’t
help with solar heat storage. Also ICFs use more
concrete (with high embodied energy) than a
typical hollow CEB wall.
Copyright © 2011 by the American Solar Energy Society Inc. All rights reserved.
Conservation Enables
Small Energy Systems
The 2-k W photovoltaic system is mounted
on a tracker. When net metering, the tracker
pays for itself, especially during the summer
as the sun rises and sets north of the east-west
axis. We designed the system to be expanded,
and someday it will also charge the family’s all-electric car.
A central feature of the home is the high-efficiency solar thermal system used for domestic
water and space heating. Heated water is conveyed through radiant tubes beneath the slab
Rob Stout ( solarrs@gmail.com) has been designing
solar homes since the 1970s. He has degrees in engineering and architecture. Stout teaches green building design at Santa Fe Community College, and his
current design work is at or very near net-zero-energy performance. For more information, see swsolar
design.com.
solartoday.org SOLAR TODA Y June 2011 41
floor to heat the space, and the mass floor stores
the thermal energy. (More about this below.)
The space- and water-heating systems use the
same solar collectors. The area of the panels, 190
square feet ( 18 square meters), represents about
7 percent of the home’s total floor area. That
would be considered less capacity than needed
in this cold climate, but with a high-performance
building shell and the high efficiency of this system, it generates plenty of energy to supply both
the heating and the hot water needs. This system
closely matches the amount of heat collected
with the seasonal heating needs, collecting more
in winter and less in summer.
In fact, the system is a concentrated solar thermal system I designed to effectively double the
amount of radiant energy falling on the home’s
solar thermal collectors during winter. The
