BUILDING ENERGY - Fall 2017 - 43

FIGURE 3: SEASONAL PERFORMANCE. WINTER
HEATING: MAXIMUM SOLAR ABSORPTION THROUGH
INCREASED SURFACE. SUMMER COOLING: INCREASED
REFLECTION, MINIMAL ABSORPTION THROUGH
SELF-SHADING EFFECT AND VENTING.
GRAPHIC BY NELSON ARCHITECH GMBH.

back-vented glass draws excessive heat out of the
system much faster, causing the absorber to warm
up less than in winter months (Figure 3).
To accomplish this, SAF's core technology
comprises: (1) the solid wood heat buffer/absorber,
which sits against a conventionally insulated wall;
(2) a back-vented solar glass fa ade applied over
the wood absorber to protect the wood from the
elements while amplifying the thermal buffering
effect, which primarily takes place on the western,
southern and eastern facing fa ades but also, in
a lesser fashion, on the northern fa ade. It is a
system that can be applied on the entire building
fa ade making it an equal substitute to any other
cladding system, with the major added value of
energy performance.
Furthermore, SAF® achieves greater passive
solar radiation results with fewer resources than
the standard Passive House method, in which
insulation of a wall to an R-value of R-60 requires
about 40 cm of insulation (fiberglass or mineral
wool). This thickens the wall, which deepens the
window reveals, decreases the living space, expends
more resources and increases insulation costs.
SAF, however, can reduce a Passive House wall
thickness of 40-50 cm by about half. Finally, SAF®
is aesthetically pleasing and provides a new tool for
architects seeking to give their buildings uniquely
warm, modern appearances.
CASE STUDIES
The Hofberg development consists of single and
multi-family residences with SAF® technology in
Wil, Switzerland (Figure 4). It was designed and built
by G. Fent, the system inventor. The first (Hofberg 1)
in a series of eight buildings was built in 2004, while
the most recent (Hofberg 8) was finished in 2016
and features the latest evolution of the system,
including integrated PV cells and a mechanically
controlled ventilation of the air gap. Each building
has a compact building volume; high performance
airtight building envelope (triple glazing windows
and SAF®); a geothermal heat pump; a mechanical
ventilation system with heat recuperation; and a
rooftop- or fa ade-integrated PV system.
In Switzerland, new construction must meet strict
energy codes, thus each building has to be modelled

FIGURE 4: HOFBERG DEVELOPMENT IN WIL, ST. GALLEN, SWITZERLAND.
ARCHITECTURE BY FENT SOLARE ARCHITEKTUR.
PHOTO CREDIT: LUCIDO SOLAR AG.

FIGURE 5: NET POSITIVE ENERGY PROJECT, "HOFBERG 6/7" IN WIL, CANTON OF ST.
GALLEN, SWITZERLAND. RECIPIENT OF THE 2012 LORD NORMAN FOSTER SOLAR
AWARD. BUILDING IS MINERGIE-P® CERTIFIED (SG-074-P) AND PRODUCES ROUGHLY
180 PERCENT OF ITS TOTAL ENERGY DEMAND.
ARCHITECTURE BY FENT SOLARE ARCHITEKTUR.
PHOTO CREDIT: LUCIDO SOLAR AG.

BUILDING

YEAR

ENERGY SAVINGS
EXCL PV

NET ENERGY
PRODUCTION
COVERAGE

ADD COST

HOFBERG 1

2004

79%*

84%**

10%

HOFBERG 2/3

2006

78%*

88%**

8%

HOFBERG 4/5

2008

83%*

97%**

9%

HOFBERG 6/7

2012

~80%*

181%***

~10-12%

HOFBERG 8

2016

~80%*

128%***

~8-10%

FIGURE 6: * COMPARED TO A SWISS STANDARD BASELINE BUILDING;
** COMPARED TO A BASELINE ENERGY DEMAND INCL. PV;
*** COVERAGE OF ENERGY DEMAND (100 PERCENT MEANS NET ZERO
ENERGY, ABOVE 100 PERCENT WOULD BE NET POSITIVE ENERGY)

for its overall energy consumption. SAF® can help
reduce the heating energy demand by up to 80%
compared to a standard building. The added cost
for SAF® and other energy efficiency measures are
about 10%, an investment that pays off in many
ways, such as higher comfort, long-term value,
better mortgage interest rates, increased living
space and, of course, all the energy savings.
All of the buildings are at least Minergie®
(Swiss energy label similar to the better known
German Passive House standard) certified or
better, several have received the Swiss Solar Award
CONTINUED ON PAGE 45

NESEA.ORG * 43


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BUILDING ENERGY - Fall 2017

Table of Contents for the Digital Edition of BUILDING ENERGY - Fall 2017

From the Executive Director: A strategic plan for emerging professionals.
From the Board Chair: Taking flight into new territory.
What is Strategic Electrification? Simply Put, It’s an Energy Transformation: A core pathway to deep carbon reduction.
Better Steam Heat: Generating steam system upgrades in New York City.
Going All the Way:What it will really take to achieve net zero energy in Burlington, VT.
Are You Forging the Weakest Link?: A deeper dive into how the quest for resilience alters the design process.
Air Quality in Your Bedroom: Nighttime Carbon Dioxide Levels in the Bedrooms of 22 Vermont Homes: Can occupants of leaky houses breathe easy in their sleep?
Inclusive Diversity Key to Sustainability: Opinion: Sustainability planning must embrace diversity.
BuildingEnergy Bottom Lines: An interview with Jonathan Orpin.
High Performance Walls: Discover an alternative to traditional insulation methods that can reach superior insulation performance with thinner walls.
SAF®– A Solar Faade to Stay?: A technical overview of the newest attachment systems in the low-energy construction market.
NESEA Green Pages: This premier resource for sustainability professionals in the Northeast and beyond is just a few pages away. To have your business listed in next year’s Green Pages and become a NESEA business member today, visit nesea.org/join.
Index to Advertisers
BUILDING ENERGY - Fall 2017 - Intro
BUILDING ENERGY - Fall 2017 - cover1
BUILDING ENERGY - Fall 2017 - cover2
BUILDING ENERGY - Fall 2017 - 3
BUILDING ENERGY - Fall 2017 - 4
BUILDING ENERGY - Fall 2017 - 5
BUILDING ENERGY - Fall 2017 - From the Executive Director: A strategic plan for emerging professionals.
BUILDING ENERGY - Fall 2017 - 7
BUILDING ENERGY - Fall 2017 - From the Board Chair: Taking flight into new territory.
BUILDING ENERGY - Fall 2017 - 9
BUILDING ENERGY - Fall 2017 - What is Strategic Electrification? Simply Put, It’s an Energy Transformation: A core pathway to deep carbon reduction.
BUILDING ENERGY - Fall 2017 - 11
BUILDING ENERGY - Fall 2017 - 12
BUILDING ENERGY - Fall 2017 - 13
BUILDING ENERGY - Fall 2017 - 14
BUILDING ENERGY - Fall 2017 - 15
BUILDING ENERGY - Fall 2017 - Better Steam Heat: Generating steam system upgrades in New York City.
BUILDING ENERGY - Fall 2017 - 17
BUILDING ENERGY - Fall 2017 - 18
BUILDING ENERGY - Fall 2017 - 19
BUILDING ENERGY - Fall 2017 - INSERT1
BUILDING ENERGY - Fall 2017 - INSERT2
BUILDING ENERGY - Fall 2017 - Going All the Way:What it will really take to achieve net zero energy in Burlington, VT.
BUILDING ENERGY - Fall 2017 - 21
BUILDING ENERGY - Fall 2017 - 22
BUILDING ENERGY - Fall 2017 - 23
BUILDING ENERGY - Fall 2017 - Are You Forging the Weakest Link?: A deeper dive into how the quest for resilience alters the design process.
BUILDING ENERGY - Fall 2017 - 25
BUILDING ENERGY - Fall 2017 - 26
BUILDING ENERGY - Fall 2017 - 27
BUILDING ENERGY - Fall 2017 - 28
BUILDING ENERGY - Fall 2017 - 29
BUILDING ENERGY - Fall 2017 - Air Quality in Your Bedroom: Nighttime Carbon Dioxide Levels in the Bedrooms of 22 Vermont Homes: Can occupants of leaky houses breathe easy in their sleep?
BUILDING ENERGY - Fall 2017 - 31
BUILDING ENERGY - Fall 2017 - 32
BUILDING ENERGY - Fall 2017 - 33
BUILDING ENERGY - Fall 2017 - Inclusive Diversity Key to Sustainability: Opinion: Sustainability planning must embrace diversity.
BUILDING ENERGY - Fall 2017 - 35
BUILDING ENERGY - Fall 2017 - BuildingEnergy Bottom Lines: An interview with Jonathan Orpin.
BUILDING ENERGY - Fall 2017 - 37
BUILDING ENERGY - Fall 2017 - High Performance Walls: Discover an alternative to traditional insulation methods that can reach superior insulation performance with thinner walls.
BUILDING ENERGY - Fall 2017 - 39
BUILDING ENERGY - Fall 2017 - 40
BUILDING ENERGY - Fall 2017 - 41
BUILDING ENERGY - Fall 2017 - SAF®– A Solar Faade to Stay?: A technical overview of the newest attachment systems in the low-energy construction market.
BUILDING ENERGY - Fall 2017 - 43
BUILDING ENERGY - Fall 2017 - 44
BUILDING ENERGY - Fall 2017 - 45
BUILDING ENERGY - Fall 2017 - 46
BUILDING ENERGY - Fall 2017 - 47
BUILDING ENERGY - Fall 2017 - NESEA Green Pages: This premier resource for sustainability professionals in the Northeast and beyond is just a few pages away. To have your business listed in next year’s Green Pages and become a NESEA business member today, visit nesea.org/join.
BUILDING ENERGY - Fall 2017 - 49
BUILDING ENERGY - Fall 2017 - 50
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BUILDING ENERGY - Fall 2017 - INSERT4
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BUILDING ENERGY - Fall 2017 - 75
BUILDING ENERGY - Fall 2017 - 76
BUILDING ENERGY - Fall 2017 - Index to Advertisers
BUILDING ENERGY - Fall 2017 - 78
BUILDING ENERGY - Fall 2017 - cover3
BUILDING ENERGY - Fall 2017 - cover4
BUILDING ENERGY - Fall 2017 - outsert1
BUILDING ENERGY - Fall 2017 - outsert2
BUILDING ENERGY - Fall 2017 - outsert3
BUILDING ENERGY - Fall 2017 - outsert4
BUILDING ENERGY - Fall 2017 - outsert5
BUILDING ENERGY - Fall 2017 - outsert6
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