was no different from any other. At times they
were over whelmed with choices — floor plan
layout preferences, exterior finish options,
color schemes, tile samples, lighting fixtures
and on and on and on.
But one fundamental choice was surprisingly easy to make — they decided to
build their new home to the rigorous Passive House energy standard. Early in the
design process, I introduced them to the
idea of the Passive House Certification,
which is a voluntary energy consumption
standard administered by the Passive House
Institute US and the Passive House Institute
in Germany.
Unlike traditional passive solar buildings,
a Passive House has very strict measurable
air-tightness criteria, as well as rigorous calculable energy consumption requirements
for annual heat demand, annual cooling
demand, heating and cooling loads and
total annual energy demand. The architect
or designer must develop a climate-specific
design using the energy modeling software in
the Passive House Planning Package (PHPP)
to fine-tune building components in order to
make the design affordable to build.
To address their concern, I used the PHPP
computer energy model to optimize insulation levels in the walls, under the slab and
in the roof. I also chose a simplified building form, employed optimal value engineering framing techniques and used standard
methods and materials to keep costs down.
The result was that the house achieved the
Passive House standard and cost only about
$9 per square foot more than business-as-usual code construction. Given this modest
cost increase, and the fact that upgrading the
energy efficiency of the home in the future
would be impractical, expensive and disruptive, the owners agreed that Passive House
was a sensible investment.
making a (Passive) House a Home
In addition to extremely low energy use,
the core goals of Passive House design are
thermal comfort and excellent indoor air
quality. By eliminating thermal bridges and
But energy efficiency doesn’t make a
house a home, and the owners had a clear
vision for how their new abode could accommodate and enhance their lifestyle. Topping
their wish list were a generous space on the
ground floor for entertaining; indoor and
outdoor dining; an open plan with lots of
diffuse natural daylight; a simple and logical
flow of spaces; views of the beautiful Wasatch
mountains; and a clean, uncluttered aesthetic. As the design materialized, it became
clear that the choice to build a Passive House
dovetailed nicely with the owners’ practical
and intangible requirements.
nicolemorGentHAu.com
A mature silver maple shades the east side of
the Breezeway House in the summer and a
2.2-kilowatt rooftop photovoltaic system provides clean, renewable electricity all year.
using airtight construction techniques, a Passive House maintains uniform interior surface temperatures even when outdoor temperatures are extreme. A dedicated energy
recovery ventilation system ensures clean,
healthy indoor air.
At first, however, these requirements
did not seem to synchronize with the site.
Although certainly not the tiniest of urban
lots, the .19-acre, slightly sloping parcel
forced us to adapt the vision to some challenging existing conditions. Orienting the
long axis of the house east toward the street
wasn’t an option, because that would practically guarantee excessive summertime
overheating and sever the sense of connectedness and movement between the green
public space in front and the private garden
in the back. In addition, the mature silver
maple tree on the north side of the front yard
pushed the driveway to the south, but also
became a perfect way to shade the east side
of the house from the hot morning sun in
the summer.
The owners questioned how much it
would increase costs to achieve these goals.
The initial schematic design for the structure — dubbed the “Breezeway House” —
had a roofed passageway, open at the front
and back, connecting the low-profile flat-roof
Copyright © 2012 by the American Solar Energy Society Inc. All rights reserved.
owners: Joe Turner and Rebecca Guymon
Architect: Dave Brach, AIA, CPHC,
Brach Design Architecture, brachdesign.com
Contractor: Mark Fisher, Fisher Custom Building Inc.
Size: 2,800 square feet (260 square meters) of “
treated floor area” (a Passive House term analogous to
“finished floor area”), 3,200 square feet (297 square
meters) measured from the exterior
Construction cost: $450,000
date completed: November 2009
insulation
Basement floor, R- 41
Basement wall, R- 35
Wall, R- 43
Roof/ceiling, R-70
glazing details
Window glass area in square feet (square meters)
North, 43 ( 4)
East, 54 ( 5)
South, 151 ( 14)
West, 54 ( 5)
Average window total unit heat transfer
coefficient (U-value), U-0.18 (R- 5. 6)
Solar heat gain coefficient (SHGC)
0.51 on south side
0.31 on others
Solar electric System
2.2-k W photovoltaic system
10 REC Solar Inc. 220-watt modules
Performance
National Renewable Energy Laboratory’s PV Watts
calculator estimates that a 2.2-k W system in Salt Lake
City will produce about 3,000 k Wh AC annually.
The Passive House energy-modeling tool predicts a
total energy consumption (heat demand, cooling
demand, hot water demand, miscellaneous household electricity) of 105 k Wh per square meter
( 9.76 k Wh per square foot) per year, or 27,090 k Wh
per year source energy and 10,030 k Wh
( 27,090/2.7) site energy.
Solar Hot water System
Two TiSun solar thermal flatplate collectors,
77 square feet ( 7 square meters)
120-gallon (454-liter) TiSun solar hot water tank
Heating System
An electric resistance element in the solar storage
tank provides space heat to supplement the passive
solar design and the solar hot water system. The
foyer floor includes backup hydronic radiant heat
for periods of extreme cold.
Cooling System
OAsys two-stage 40 SEER evaporative cooler,
ducted separately from the ventilation system
energy recovery ventilator
UltimateAir RecoupAerator 200DX
Breezeway House
Project details
