Affordable Passive Solar Homes

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Floor plan for and FmHA passive solar home.
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Passive solar homes and meet FmHA design guidelines include wide eves for shade and south facing windows.
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The bricks behind these windows collect heat during the day and radiate it back into the house when the thermal shades are drawn.
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An FmHA-approved passive solar home.
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Central heat storage wall.
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The north side of this passive solar home has a minimum of windows to limit heat loss.
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Cabinetmaker Al Marek shows what can be done with a little barn wood and time.
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The "trombette wall" serves as both a storage area and heat storage medium. 
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A wood stove provides backup heating.

It’s not too often that we here at MOTHER EARTH NEWS get a chance to
compliment our federal government. So, when such
an opportunity does arise, you can bet that we’ll play it
fair and square and let folks know where some of their tax
dollars are being put to good use.

Now since this article deals with passive solar homes,
you might expect that our kudos will be directed toward an
energy -related branch of our republic’s
management. But, unusual as it may seem, in this case the
credit has to go to the Farmers Home Administration, a
division of the United States Department of Agriculture.

Mom, a Home, and a Piece of the Solar Pie

The FmHA is, you see, the “credit” arm of the USDA. It
provides low-interest housing loans to qualified
people for the construction of some 110,000 homes and
apartments annually in rural locales. (Such areas, for
eligibility purposes, are defined as either open country or
towns with populations of less than 20,000.)

As a decentralized agency with 1,884 county offices
throughout the nation, the FmHA is able to relate–at
a grassroots level–to people who need to borrow
affordable money not only for shelter, but also to
provide new employment, start businesses, or help purchase
or operate farms. However, far from being yet another big
government “giveaway” plan, the Farmers Home program relies almost totally on insured loans. Such loans are made and
serviced by federal personnel but use private capital
obtained through the sale of notes. The 100% mortgage funds
are available–at interest rates as low as one
percent–to families with annual adjusted incomes of
no more than $15,600. The difference between the
borrower’s and lender’s premium is the “tab” that comes out
of the federal till.

Making home ownership possible for those who can’t
afford high-interest housing, the FmHA people
believe, will bolster the rural economy by encouraging
responsible people to settle and work in such areas.
Furthermore, the resulting construction can provide jobs
for local builders, contractors, and tradespeople which might otherwise be difficult to find.

Of course, the FmHA isn’t just a money-lending agency. It
has, in fact, a comprehensive program that embraces
everything from actual structure design to public relations and is involved in bringing its services to the
attention of businesspeople, planning groups, and local and
state officials, as well as to possible recipients.

Until recently, Farmers Home Administration architects were
concerned with structural soundness, practicality, ease of
construction, and low cost, but not necessarily with energy
conservation. Now, however, thanks to the efforts of some
progressive folks at the state level, simple passive solar
techniques are being incorporated into the agency’s basic
home designs without spoiling the integrity of the
structures, thus making sun-powered dwellings
available at prices that have already proved to be equal
to–or at most only 5% more than–those of similar-sized conventionally-heated homes!

The man behind this “solarization” is Robert Andron, one of
the FmHA architects assigned to the North Carolina area.
Several years ago, as head of his own design firm, Bob
worked up a number of plans in which solar energy played a
major role. (He actually started using the sun in his
layouts long before the notion was popular, and attributes
some of his concepts–and a lot of his
inspiration–to the pages of MOTHER EARTH NEWS!) So when he
signed on with the federal team, Bob saw no reason to put a
good idea to rest.

Mr. Andron knew, in short, that he could take a typical
two- or three-bedroom suburban tract house, and–using
low-tech solar hardware–turn the structure into a
practical sun-heated dwelling.

The “Volkswagen” of Solar Homes

The houses being financed under the FmHA “small home”
program range in size from about 900 square feet of heated
area to slightly over 1,000 … although such additions
as carports, outside storage areas, and porches can add to
the structures’ overall size. To hold building costs down,
great care is taken to keep the plans as conventional as
possible so as not to confuse contractors and suppliers
with unfamiliar techniques or materials (which they might
construe as “custom”–that is, expensive–work).

As a result, the bottom line for these
homes–excluding such things as land and septic
system, and depending upon locale–ranges from $29,000
to about $35,000 for a contractor-built package. Owners who choose to construct their own homes can reduce the price substantially. (Fortunately, the
FmHA program allows applicants a great deal of flexibility
in the design, construction, and decoration of their
abodes, and will even provide contacts and professional
consultation for any program participants who wish to
become intimately involved in the creation of their “castles.”)

The structures themselves depend on three standard
techniques to achieve at least partial energy independence:

[1] They’re oriented ten degrees east of due south to
reduce insolation from the west on sultry summer afternoons
while still taking full advantage of the light and heat
available in the winter. Protective roof overhangs are also
included in the designs, to prevent the rays of the high
“dog days” sun from directly entering the homes.

[2] The insulation goes beyond the requirements of normal
state and local codes to hold both artificial and natural
heat in the dwelling. The walls of the homes are equipped
to an equivalent of R-19, and the ceilings protected to an
R-30 level (the foundation walls or slabs also have rigid
styrofoam lining). Equally important, all the south-facing
windows are furnished with thermal curtains: frame-fitted
roll-up quilts that prevent heat collected during the day
from escaping out the windows at night.

[3] Each house is equipped with low, broad “Trombette”
walls … which are actually brick thermal storage masses
placed four inches behind large, double-glazed windows or
sliding glass doors on the south side of the structure.
Unlike “conventional” Trombe walls (which, because of their
size, are often both imposing and light-restrictive), the
pint-size partitions do a more-than-adequate job of storing
daytime warmth–and releasing it for up to six hours
in the evening–while still allowing natural light to
enter above the walls … and can even function as
attractive planters or shelf units. By the same token, if
for any reason a resident chooses to shut out daylight, the
thermal shades can be partially drawn to the level of
the brick bulkheads’ upper surfaces without
sacrificing the heat storage capabilities of the system.

Beyond those basics, care was taken to make the home
designs both flexible and attractive. For example, the
North Carolina plans provide for main entry from the north,
south, or east to allow construction in virtually any
subdivision. Material, trim, and color options
are left completely to the builder or buyer. The backup
thermal system is currently zone-controlled electric
baseboard heat, but those homeowners with adequate supplies
of timber can use wood stoves too, if they wish. Extra
summertime cooling is taken care of by a ceiling-mounted
“whole house” attic fan that “sweeps” the structure from
the floor upward.

Ask the Man or Woman Who Owns One

Because the first FmHA passive solar homes were completed
only last year, comprehensive performance figures are not
yet available on a statewide level. But, if the experience
of the owners is any indication of the success of the
design, it looks as if the Farmers Home folks have a real
winner. MOTHER EARTH NEWS’ editors spoke with several one-year
residents of the solar dwellings and heard nothing but good
from every one of them.

As an example, Al Marek–a cabinetmaker in Milton,
North Carolina–and his family didn’t use even two
cords of wood to heat their home during this past cold
season, and two other families in the city of Wilson enjoy
noticeably lower utility bills than do their neighbors in
all-electric conventional houses. In fact, calculations
based on the original plans indicate that a full two-thirds
of the structures’ energy needs can be provided by the sun. Some North Carolina owners report even greater

Plans Are Available

Folks who are interested in the Farmers Home
Administration’s loan program should get in touch with
their FmHA county supervisor for more information. (He or
she will usually be located in the federal office at the
county seat … the address and telephone number can be
found in your Yellow Pages under “Government
Offices–U.S.” among the listings for “Agriculture,
Department of”. If you can’t find a representative in your
area, try the agency’s state office in the capital city.)

Even people who aren’t eligible for the program, and yet
are curious about the houses themselves, can
obtain–for $5.00–plans for the latest (FmHA-2)
passive solar home. Good news should be shared, and the
Farmers Home Administration is more than willing to do just

Need Help? Call 1-800-234-3368