The front entrance of the
Missouri Heights Residence is elegant yet understated in a way
that gives no hint that this is a high-tech, superbly designed
Credit: Pat Sudmeier
Missouri Heights Residence
The Missouri Heights Residence in Carbondale, Colorado, is the winner of
the CRES 2005 Renewable Energy in Buildings Award in the category of
The Missouri Heights Residence is a home with a very high solar fraction
of 85%, which means it obtains almost all of the energy it needs from
the sun. There are some homes in Colorado that obtain 100% of their
energy from the sun, but that usually costs extra for energy storage,
etc. The owners of this house work at home and sought to create an
environmentally friendly residence that could be constructed within
their budget. According to their calculations, they built this home at a
cost that was “very competitive” with that of conventional homes built
Because the solar and
energy storage features of this home are included in the
structural design of the building, it is possible to be in
this home and not know it is heated almost entirely by the
Credit: Pat Sudmeier
Use of Renewable Energy
There are a number of very innovative design features of this home,
including passive solar design and a greenhouse, which together comprise
the primary heat source. To make this work, concrete floors and two-foot
thick cast-earth walls create a thermal mass that stores heat energy
when the sun is shining for later use. Thermal mass tends to moderate
indoor temperature fluctuations year round and is a critical element of
solar design. The concrete floors have pipes installed in them for
radiant heating. When the sun is shining, a pump moves fluid through the
floors to distribute heat energy of the sun through the floors.
The owners report that the temperature swings 5 degrees Fahrenheit (F)
from warm weather to cold weather, which shows that the solar design and
thermal mass are working well together.
Backup heating is from a natural gas fired high-efficiency boiler, which
also provides backup heat for domestic hot water. Solar hot water panels
on the roof supply the majority of the energy for heating domestic
water. The walls are straw-bale construction with an R-48 high
The home takes advantage of natural ventilation and daylighting. There
is no air conditioning, and the owners report that summer indoor
temperatures were 73 F when outdoor temperatures were 90 F. General
lighting is with compact fluorescent fixtures.
For electricity supply, the owners installed a PV system rated at 1.8 kW
on the rooftop that connects with the local utility, Holy Cross Electric
Company, through a single meter (called net metering). The PV system
supplies about 40% of the total electricity consumed in the house. The
owners also purchase 100 kWh per month of electricity from Holy Cross
under the company’s green pricing program, Wind Energy Pioneers.
plants and trees surround the Missouri Heights Residence,
which allows the structure to blend beautifully into the
semi-arid mountain landscapes around Carbondale.
Credit: Pat Sudmeier
Low Environmental Impact
The designers took a number of steps to reduce the environmental impact
of construction. They chose low-maintenance building materials that were
obtained locally and compatible with natural surroundings. The house is
framed with FSC certified lumber. A whopping 99.8% of construction
materials were produced in the United States, most of this from nearby
Carbondale. There are lots of recycled materials, including metal for
roofing, reclaimed wood siding on the garage, and master shower tiles
made from recycled glass.
The owners paid special attention to landscaping and gardening. They
located the house on an old road cut nestled in a juniper and pinon
grove that protects the structure from winter winds. Ground disturbed
during construction was replanted in native grasses and wildflowers. A
rooftop garden increases ceiling insulation to R-57 and reduces water
runoff during rainstorms.
Winning Design Team
The design and construction team was led by Graybeal Architects, LLC, in
The other partners involved were:
- Resource Engineering Group, Inc.
- White Horse Consultants, Inc.
- David Nelson & Associates, LLC
- Wolf Brand Construction, Inc.