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Issue
#6 |
Welcome to the ENVELOPE issue of the Affordable Energy News, an information source to help you make homes more affordable through energy efficiency. Aimed at the affordable housing market within Southern California Edison's service territory, this newsletter seeks to provide up-to-date information on energy efficiency topics such as funding sources, technologies, training, and case studies. | |
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In this issue... The
First
Steps in Energy Efficiency: Orientation and Sunshades Sealing
the Building Envelope: Reducing Infiltration and Drafts Selecting
the
Right Glazing: Windows, Doors and Skylights
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The
The Enterprise
Foundation is a national nonprofit and the leading provider of capital
and expertise for affordable housing and community development.
The foundation offers a number of financial products, including
acquisition and predevelopment lending, asset management and compliance,
low-income housing tax credits, grants and permanent financing. A
number of informational resources are available through the Enterprise
Foundation website, such as resource and funding databases, newsletters,
and tutorials. Through the Green
Communities Program, the Enterprise Foundation offers planning and
construction grants to help cover expenses associated with planning and
implementing green components of affordable housing developments.
Planning Grants help housing developers engage in a serious discussion
of green design possibilities. For instance, Please visit www.enterprisecommunity.org
to discover all that the Enterprise Foundation has to offer. For
more information on Green Grants for planning and implementing green
components of affordable housing developments, visit www.greencommunitiesonline.org/about-essentials-grants.asp. Remember
that SCE’s California New Homes Program can help meet the energy
efficiency element of your green building goals. The program
offers cash incentives and design assistance to help offset the cost of
a high performance building. For more information visit www.sce.com/builder.
Energy
Efficient Design from Project Beginning: Building Orientation Every building site comes with a unique
set of climate conditions. Two dominating influences on a site are the
sun and the wind. The building design elements that interact with them
are building shape and orientation. The opportunity to create a building
design that takes full advantage of this relationship only occurs once
in a project—at the earliest stage of the design process. Each building surface will respond
differently to climatic conditions depending on which direction it is
facing, and what materials it is made of. In Don’t skip the
important first step of designing the project to address the site and
climate conditions. For information on building orientation and
shading, please visit www.consumerenergycenter.org/home/construction/solardesign/orientation.html
Sealing
the Building Envelope: Reducing Infiltration and Drafts Infiltration is the
unintentional exchange of conditioned air with unconditioned air through
cracks and leaks in the building envelope. Sealing these cracks and
other leakage sources prevents this loss of energy, and also helps
prevent moisture infiltration, making living spaces draft free and
greatly improving comfort. Many insulation
materials do a poor job of resisting air flow, so must be contained by
an air barrier. An air barrier can be any material that restricts air
flow without any holes, cracks or gaps, and must be in full and
continuous contact with the insulation. Typically, the air barrier will
be the drywall on the inside of the exterior wall or the underside of
the ceiling joists, or the floor sheathing. Continuous insulation
sheathing can also act as an air barrier. Other important
measures for a well-sealed building include weather-stripping around
doors and windows, caulking around holes cut for pipes and electrical
wiring, and covering fireplace openings with glass or metal doors.
These measures will both reduce the load on mechanical heating and
cooling systems and prevent uncomfortable drafts. For more
information on achieving a well-sealed building envelope, please visit
the Building Envelopes Program at Oak Ridge National Laboratory (ORNL)
website www.ornl.gov/sci/roofs+walls/.
Heat flows through the
building materials and air between zones of differing temperatures, such
as outside to inside or between livable spaces and the garage. Insulation, when
installed correctly, minimizes heat flow through walls, ceilings, and
floors, keeping a home comfortable and reducing the need for heating and
cooling. Forms
of Insulation The most common forms
of insulation in residential construction are blanket insulation and
blown-in insulation. These are made up of either fiberglass (sand
and recycled glass) or cellulose (shredded or ground up newspaper).
Blanket insulation comes in the form of batts made up of mineral fibers.
They are available in widths suited to standard spacings of wall studs
and attic or floor joists. Continuous rolls can be hand-cut and
trimmed to fit. Blown-in insulation is made up of loose fibers or
pellets that are blown into building cavities or attics. These
fibers may also be sprayed in with an adhesive to reduce settling.
Additional types of insulation include foam board insulation and
reflective systems. Foam board is manufactured by blowing molten
liquid or pellets into air spaces and is installed as continuous layer,
rather than between framing, thus eliminating thermal bridging.
Reflective systems use high reflectance, low emittance foil with a
variety of backings, such as paper, plastic, polyethylene bubbles, or
cardboard. The energy performance
of insulation is indicated by the R-value, a measure of a material’s
resistance to heat transfer. Quality
of Installation In addition to the
rated R-values of insulation products, factors such as the percentage of
the wall taken up by framing members, and the quality of the
installation, must be accounted for to calculate the effective R-value
of a wall, floor or roof assembly as a whole. Studies of building
energy performance often show a significant gap between the specified
level of insulation and the actual performance of wall, roof, or floor
assembly. Many of these shortfalls are related to improper installation
techniques. Thermal performance decreases when insulation: w
Is not in contact with the air
barrier, allowing air to flow past the insulation. w
Have voids or gaps, leaving
portions of the construction assembly without insulation. w
Is compressed, reducing the
thickness of the insulation. The 2005 Building
Energy Standards address these common insulation problems with the
Quality of Insulation Installation (QII) HERS measure for wood framed
assemblies. A standard R-value calculation method is used for the
effective R-value used in Title 24 compliance. If the insulation on a
building is not to be inspected by a HERS rater, the standard value is
reduced by 13%. If inspected by a HERS rater following the procedures of
the QII HERS measure, then a Title 24 compliance credit is available,
which restores the effective R-value to the standard calculation value. The Thermal Bypass
Checklist ( For more information on
insulation products and installation practices, please refer to the
following list of resources.
Selecting
the Right Glazing: Windows, Doors and Skylights Historically, windows
have been the weak link in the thermal envelope. Single pane windows,
which are commonly found in multi-family apartment buildings at least 25
years old, are more like a hole in the wall than a thermal barrier and
they can lose heat ten to twenty times faster than a well insulated
wall. The introduction of dual-glazed windows is a great improvement,
with the insulating value almost doubling. There is a lot
more to improving window performance than just adding more glass. The
type of materials used for the frame, sash, and spacer will also affect
window performance, as will the type of gas between layers of glazing
and types of coatings on the glazing layers. The National
Fenestration Ratings Council (NFRC) provides an independent evaluation
of whole window performance based on three basic window properties:
The U-factor and SHGC
are the essential values that are input into Title 24 compliance
software and will have significantly different effects, depending on
whether the building is in a heating or a cooling climate. Window selection is not
as simple as selecting a window with the “best”, i.e. lowest,
performance values. Each climate zone will have its own characteristic
mix of heating and cooling days throughout the year, and within a given
climate each building design is unique. The best option will vary
accordingly and depend on loads and efficiency of systems. Sometimes
choosing the “best” window may result in cooling energy savings, but
increased heating energy, thus negating the net gain from such
high-efficiency windows. Only computer
simulation, either with a specialized window program like RESFEN
or Window5, or on a whole house basis with Title 24 or other building
simulation programs, can provide climate specific guidance as to the
most cost-effective choice of window performance. The best computer
simulations take into account the specific thermal properties of the
windows, their exact surface area and orientation, the specific climate
zone they occur in, and the dimensions and position of shading devices.
Ask the energy consultant performing the Title 24 project calculations
to assist in this analysis. For an approximate
guide, the Efficiency Windows Collaborative has performed computer runs
on nine For information on SCE's multi-family affordable housing incentive programs, please see programs and contact information below: New Construction: For information
on SCE's California New Homes Program, please visit www.h-m-g.com/multi-family/CANHP
or contact Colin Jessop at 760-436-7005 or Rehabilitation of Existing Buildings:
For information on SCG/SCE's Designed for Comfort Program, please visit www.DesignedforComfort.com
or contact Elizabeth McCollum at 760-436-7001 or Affordable Housing Design Assistance
and Charrettes: For more information on SCE's Affordable Housing
Energy Efficiency Alliance, please visit www.h-m-g.com/multi-family/aheea
or contact Julieann Summerford at 760-436-7002 or
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This program is funded by California utility ratepayers and administered by Southern California Edison Company under the auspices of the California Public Utilities Commission, through a contract awarded to Heschong Mahone Group. California customers who choose to participate in this program are not obligated to purchase any additional services offered by the contractor. The trademarks used herein are the property of their respective owners. SCE reserves the right to modify or discontinue this program at its discretion or by order of the CPUC. Este programa es financiado por los usuarios de las compañías de servicios públicos de California y es administrado por Southern California Edison Company bajo los auspicios de la Comisión de Servicios Públicos de California mediante un contrato con Heschong Mahone Group. Los contribuyentes de California que decidan participar en este programa no están obligados a comprar ningún servicio adicional ofrecido por el contratista. Las marcas registradas usadas aquí son propiedad de sus dueños respectivos. SCE se reserva el derecho a modificar o interrumpir este programa a su criterio o a pedido de la CPUC. If this newsletter was
forwarded to you, and you wish to subscribe click here to send email. Heschong Mahone Group, Inc. 144 West D Street, Suite 24, Encinitas, CA 92024 |
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