SOLAR TODAY - January/February 2011

an adjacent apartment complex. With an 800-square-foot footprint, the
house is only 1,200 square feet of living area (111 square meters). Con-
ditioned space, however, is equivalent to that of a 2,000-square-foot
home, due to a short (4-foot) basement and an open double-height
space reaching to 20 feet ( 6 m). Fulfilling the original intention, this
house is basically a habitable wall
along the edge of the property. At
only 17 feet (about 5 m) wide (the
extra thickness the Passive House
standard requires enlarged Saft’s
original plans) and 52 feet long ( 5
by 16 m), the project was also an
investigation for future urban infill
projects. As well as being ultra-con-
temporary, the form matches closely
to the traditional camelback shotgun typology, a good fit for the regional
climatic systems.
The formal strategy maintains a simple, narrow footprint but is enliv-
ened through overlapping territorial volumes and alternating expan-
sive and compressed views. A simple shed roof allows northerly light
to illuminate the space inside while accommodating thin-film solar PV
his 3. 3 kW). Since Saft’s system has no battery storage, he is waiting
until the local utility company offers some refund mechanism for the
surplus he produces (right now it offers only a credit) before he expands
the system.
The showpiece of the home’s interior is a double-height volume with
an overlooking loft. This room com-
prises living, dining, circulation and
kitchen functions. One bedroom
and a bath are downstairs off the
main room. Two more bedrooms,
with another full bath, are upstairs.
The length of the home is oriented
approximately east-west to make the
most of the solar and wind possibili-
ties while minimizing the heat gain. Windows are grouped together to
maximize impact and carry through the contemporary aesthetic of the
home. Artificial light is required only in the evening, and then a mixture
of CFL and LED lights minimizes the energy draw. The windows are also
strategically located low on the south wall and high on the north wall to
Photovoltaic System
Production
Estimated Annual Output
first year: 5,354 k Wh
Estimated Annual Output
per day: 14.67 k Wh per day
Average solar hours/day:
4. 5 hrs
Mechanical Systems
UltimateAir’s 200DX ERV
RecoupAerator
AirGenerate’s A5 Air Tap
water heater
Daikin RXS18/FTX18
heat pump
Emerson Loft ceiling fan,
model CF765BQ
Energy Star appliances
throughout
CFLs and LEDs throughout
Insulation
Exterior walls: R- 28
Roof: R-55
Crawl space: R- 21
Slab: R- 16. 5
Doors: R- 8
Windows: R- 6 +

intensify both stack and cross ventilation.

The project broke ground in June 2009. The construction was largely
undertaken by one of Saft’s former students, Jaron Young, and his com-
pany, H.J. Construction in Lafayette. The contractors’ appreciation for
the experiment and their desire to pioneer this new market were essential
to making this an affordable prototype. One of the main difficulties, in
fact, in building a project like this is the financing. The appraisal that the
underwriting of a traditional construction loan requires rarely accounts
for the innovative efficiencies in a home like this because there are no
“comparables” against which a lender can judge how much a consumer
might pay for them. The result is that they simply are not factored in
and the home is undervalued. This financing gap, says Saft, is probably
the most significant impediment to a large-scale transformation of our
building stock.

creating an ultra-efficient Whole-house System

Louisiana’s extreme climate made the home’s environmental strategy
as important as the formal and spatial strategies. The home is super-
insulated and extremely well-sealed, preserving the conditioned air inside
and consequently requiring much less overall conditioning of air. Because
of the open plan, sealed building envelope and the high insulation values,
Saft was able to rely on a 1.5-ton ductless mini-split heat pump to heat
and cool the house; if it weren’t for the extreme humidity it could work
with less than 1 ton. To be successful with such a small setup, though,
required that the whole house be thought of as a system — and this is
really the heart of the Passive House strategy.
The heat pump is supplemented with UltimateAir’s RecoupAera-
tor energy recovery ventilator (ERV) with MERV12 filtration, which
operates on 110v power ( ultimateair.com). This ERV exchanges the
stale air of the entire house with fresh, filtered air every two hours at a
heat-recovery rate of up to 95 percent. The ERV dehumidifies as well as
cools incoming air before the mini-split further conditions it. The final
link in the mechanical system is an Air Tap air-to-water heat pump for
domestic hot water and supplemental air conditioning and dehumidifi-
cation ( airgenerate.com). This unit not only runs on a single 110 plug,
but it also allows Saft to disconnect the 220v service for the water heater
through much of the year. The systems in the house are all standard and
readily available, but it is their integration into a whole-house strategy
that makes the final product so efficient and unique.

The wall assembly manages most of the thermal issues. Passive House
guidelines recommend the use of advanced framing techniques and heavy

Consultants
Architect: Corey Saft, CSDesign, Lafayette, La.
Whirlwind Solar: Fred Reardon, Whirlwind Solar Energy Systems,
Houston
Solar Install: Balance of electrical system install by Jerry Meche,
A-Plus Services, Lafayette, La.
Builder: Jaron Young, HJ Construction, Lafayette, La.
Passive House: Katrin Klingenberg, Passive House Institute US |
PHIUS, Urbana, Ill.
LEED: Chip Henderson, Contects – Consultants & Architects, San
Antonio
Mechanical: Jerry Meche, A-Plus Services, Lafayette, La.
Plumbing: Mitch Meche, Mitch Meche Plumbing, Church Point, La.