FAQ:
Frequently Asked Questions
on energy efficiency and building
science
This is a short list of the most frequently asked questions
at Southface. Many questions can be answered by perusing the
fact
sheet and publications section of this site. You can call
Southface and pose an energy efficiency or building science
to staff
and they will make every attempt to provide a good, non-biased
answer: 404/872-3549 ext.0
Crawlspace moisture
Q: I sometimes get standing water on the dirt floor of my
crawlspace, and I’m starting to worry about mold appearing.
What is the best way to deal with water getting into a crawlspace?
A: There
are a number of steps to take to eliminate the water getting
into your crawlspace. Because moisture is the cause
of mold, the first step is to make sure that rainwater is being
directed as far away from the house as possible. The soil next
to the foundation should have at least a 5 percent grade sloping
away from the house, and gutters should release water approximately
8 to 10 feet away from the house. Also, make sure that the
gutters and downspouts are not disconnected or leaky, because
this can lead to puddles forming next to the foundation, which
can then leak into the crawlspace. The next step is to put
down a continuous, sealed layer of 6-mil polyethylene plastic
sheeting on the floor of the crawlspace. It is important to
seal the plastic to the wall and any seams in the plastic to
insure that moisture rising from the soil is prevented from
entering the crawlspace. More information is available at the
following websites:
Crawlspace Moisture and Mold www.energy.wsu.edu/
; Crawlspace Moisture Control www.dom.com
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Vapor barrier installation
Q: What kind of material is best to use for a vapor barrier – kraft
paper, housewrap or polyethylene?
A: In Georgia’s climate, which can be hot and humid outside
for most of the year, it is a bad idea to use polyethylene
plastic as a vapor barrier. In many situations, since polyethylene
is such an effective vapor barrier, it often acts to prevent
wet areas from properly drying. Housewrap is meant to be an
air barrier and has very little effectiveness as a water vapor
barrier. Therefore, when required by code in Georgia to use
a vapor barrier, it is probably best to use kraft paper, or
a material with a similar perm rating of approximately 0.5 – 1
that allows for periodic drying if wetness occurs. And remember
to face it on the outer side of insulation in the wall cavity.
You can find a list of perm ratings of common building materials
at:
www.energy.state.or.us
or Wall
Insulation factsheet by Southface
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to top Green architect/engineer list
Q: We are building a new office for our company and are interested
in energy efficiency options. Do you have a list of architects
and engineers who specialize in environmentally friendly, or “green” projects?
A: Southface does not
currently have a list of architects and engineers who specialize
in green building. One resource
is at www.greenbuilder.com/directory.
Another option would be to inquire with architects that you
are talking with
if they have any experience with the USGBC Leadership in Energy
and Environmental Design (LEED) certification for commercial
buildings. Or if doing a local residential green-building program,
consult with www.usgbc.org. Definitely be sure to ask about
the professionals’ past projects that have emphasized sustainability
and green building practices. There is also a regional listing
created by the Western North Carolina Green Building Council.
The 2002-2003 version is available for downloading at www.wncgbc.org/directory.htm but
the 2004-2005 version has not been published yet in PDF format.
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Pressure-treated lumber alternatives*
Q: I am concerned about my daughter’s school using treated
lumber for the construction of playground equipment. What are
the health issues with treated lumber and what are the alternatives?
A: Wood referred to as “treated” lumber has typically been
pressure impregnated with Chromated Copper Arsenate, or CCA.
The primary health concerns related to CCA-treated lumber have
to do with arsenate, which is derived from arsenic and has
been linked to increased rates of liver, kidney and other cancers
as well as immune system and cardiovascular illnesses. The
EPA announced recently that CCA-treated lumber will not be
available for residential use (effective December 2003). Fortunately,
there are already a number of alternatives on the market, including
ACQ- and CBA-treated wood, borate-treated wood, naturally resistant
hardwood and recycled plastic lumber. It is always best to
get sustainably harvested varieties. For more information on
alternatives to CCA-treated lumber, please visit The Alliance
for a Healthy Tomorrow at www.healthytomorrow.org.
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to top Can’t a house be too tight? *
Q: If you air seal all the openings in a house, doesn’t that
allow radon, dust, and carbon dioxide to build up to dangerous
levels inside the house? I’ve always been told that a house
needs to “breathe.”
A: It is true that a house
needs to exchange outdoor air at fairly regular intervals.
However, in most homes, many of the
holes and leaks that might bring in outside air actually draw
that air in through basements, wall cavities, crawlspaces and
attics. These are areas that can have extreme temperatures,
humidity, insulation dust, insects, mold and other particles
that nobody would want in the air that they breathe. The reason
for building an airtight “building envelope” that contains
all the livable space in the house is to make sure that all
of the air that is brought in is controlled. Air that is brought
in through controlled channels is able to be filtered, dehumidified,
and adjusted to the proper temperature, all of which saves
energy and results in a healthier, more comfortable home. For
more information, please visit the following pages:
Airsealing
Factsheet by Southface; Healthy House Institute’s Tight
Houses article www.hhinst.com .
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to top Energy code questions
Q: Where can I get a copy of the new Georgia Energy Code,
how does it work, and how do I know if I am complying?
A: There are several new components of the Georgia 2003 Energy
Code. The most important for residential buildings are the
International Energy Conservation Code (IECC) 2000 Edition
and the Georgia State Amendments. The Department of Community Affairs
website: www.dca.state.ga.us.
It is also possible to download a copy of the Georgia State
Amendments from this website, as well as REScheck and COMcheck
software, which are methods of building compliance. For commercial
buildings, the Georgia Energy Code refers the ASHRAE 90.1 2001
edition Energy Code for Commercial and High-Rise Residential
Buildings. The Energy Code basically works by making sure that
a building, including its components (insulation, walls, windows,
etc.) meet a certain level of energy efficiency. There are
three methods used for compliance: the single-step prescriptive
package, the REScheck and COMcheck software and the systems
analysis method involving energy use simulation and comparison
to a “standard” building.
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to top Basement insulation
Q: What are the requirements for insulating a basement in
Georgia? I am finishing my basement and want to follow the
current Energy Code.
A: There are a number of ways to meet energy code requirements
for basements. The prescriptive method, which is the easiest,
requires a minimum of R-7 insulation for basement walls. If
the basement is used as a living space and inside the ‘building
envelope’, the insulation must be on the walls. If the basement
is unfinished and not used as a living space, it may be either
on the walls or on the ceiling of the basement (under the first
floor). There are a number of methods, such as increasing insulation
elsewhere in the home, which can increase or decrease the amount
of insulation in the basement. However, you may not drop below
R-5, regardless of these other changes.
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to top Pros and cons of different insulation types Q: What are some of the pros and cons of different insulation
types? Are there any that are considered generally better in
all aspects?
A: There are many different types of insulation, from the
common fiberglass batts to recycled cotton to spray-in foam,
and each has its own advantages and disadvantages. The actual
insulating value is measured in thermal resistance, or its
R-value. The higher the R-value per inch, the better it insulates.
However, how well your home is sealed from air leaks and how
tightly the insulation fits in the walls or ceilings can also
affect temperature and comfort. Health and environmental effects
can also vary between different types. You can find a quick
explanation of the different types of insulation at Home Insulation
Choices: www.weatherization.org
There is a great article that covers the differences between
insulation types from health, environmental, and insulating
viewpoints from Environmental Building News:
www.buildinggreen.com
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to top Sizing Heating, Ventilation & Air Conditioning systems (HVAC
equipment)
Q: How do I know that the HVAC company I’m using is selling
me the right size equipment? Is there a way to tell if it’s
oversized by how long it runs?
A: Standard guidelines for sizing equipment for today’s homes
often result in a mismatch. Insist that equipment be sized
according to the Air Conditioning Contractors Association of
America (ACCA) Manual J, or similar procedures. Sizing equipment
by simple rules-of-thumb methods (for tons of air conditioning
per square foot of living area) isn’t acceptable. A house’s
orientation, shade, window area, insulation and air leakage
can dramatically affect heating and cooling needs. Sizing the
equipment for your home using Manual J is important and is
often provided as a free service by utilities or contractors.
You can contact Southface at www.southface.org to have a Manual
J calculation done or to find contractors who provide this
service, go to www.acca.org. There is also a do-it-yourself
calculation at www.mrhvac.com/manualjshort.htm.
Proper sizing is particularly important for air conditioning
in the Southeast. Units that are too large cycle on and off
quickly and don’t run long enough to wick moisture from the
air. The result can be cool but clammy air and high humidity
levels inside the house. This can affect indoor air quality
lead to unhealthy living conditions.
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to top Mold cleaning*
Q: I know that mold can be hazardous to human health, so how
can I remove mold or clean an area that has been taken over
by mold?
A: Mold indeed is a health hazard and
can be remediated by a contractor or can usually be a do-it-yourself
project if the
area is less than 10 square feet. However, if there has been
substantial water damage and/or mold growth covers more than
10 square feet, consult the U.S. EPA guide: Mold Remediation
in Schools and Commercial Buildings. Although focused on
schools and commercial buildings, this document is applicable
to other
building types. It is available on the Internet at: www.epa.gov/iaq/molds/mold_remediation.html.
Some mold cleanup tips: fix plumbing leaks and other water
problems as quickly as possible; scrub mold off hard surfaces
with a detergent/water mixture and dry completely, clean/dry
moldy surfaces before painting. Porous materials, such as ceiling
tiles and carpet, may have to be thrown away if they become
moldy, due to the mold growing into the empty spaces and crevices
in the material. Above all, take precautions while cleaning
up by wearing a protective gear including a respirator, gloves
and eye goggles.
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to top Attic fans vs. whole house fans
Q: What is the difference between attic fans and whole-house
fans? Are there advantages/disadvantages of each, and in what
circumstances are each recommended?
A: There is quite a difference involving attic fans and whole
house fans, in both form and function. Whole house fans are
much larger in size and are placed somewhere in a central location
of the house’s ceiling. These fans are an efficient way to
cool a home, moving a decent amount of air through the house
and up to the attic area. They can be run at all times during
warmer months, but are most efficient when outside temperatures
and humidity levels are not extreme enough to warrant using
an air conditioner. This is because a whole house fan can only
cool the interior of a house to the outside temperature and
cannot dehumidify the inside. Another possible drawback to
operating this fan is that they can also draw in outside dust
and pollen.
Attic (or roof) fans are usually much smaller in size and
are usually placed on the interior roofline of a house. These
fans are intended to circulate heated air from the attic space
to the outside, but can create negative pressures in a home.The
pressure can: remove conditioned air from the house through
ceiling leaks and bypasses; pull pollutants such as mold, radon
and sewer gases inside the house and lastly, the pressure can
back draft fireplaces, water heaters and fuel-burning appliances.
Roof fans are generally not recommended for most house designs.
Whole
house fan fact sheet from Southface.
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to top Attic insulation Q: What is the recommended R-value for attic insulation, and
is that the same as the value required by the updated Georgia
Energy Code that went into effect in 2003?
A: The recommended R-value for attic insulation for the majority
of the state of Georgia is R-30. The very north/northwest (mountainous)
part of Georgia has an R-38 attic insulation recommendation.
The new Georgia Energy Code only requires R-19 attic insulation
for newly constructed homes in the entire state, but again,
R-30 is recommended. More information on this can be found
on the Internet at www.dca.state.ga.us or www.energycodes.gov.
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to top Graywater codes and options
Q: Can I use my dishwashing water for my yard? How else can
I conserve water?
A: At the present time, graywater is legally a somewhat “gray” issue
in the state of Georgia. This practice involves recycling your
wastewater for landscape purposes. Wastewater from sinks, bathtubs/showers
and washing machines is relatively clean and can be captured
and filtered before use on landscapes. Check with city/state
ordinances and knowledgeable professionals or www.dca.state.ga.us before using gray water.
There are both inside and outside steps that can be done to
save on water and money. You can easily start inside your home
by fixing leaks, doing full loads of laundry, avoiding wasteful
habits and not using your toilet as a trash can. Other steps
include purchasing low-flow showerheads, low flow (1.6 gal.)
flush toilets, waterless urinals and by insulating your water
heater with an insulating jacket. Most of these water-saving
fixtures can be purchased at local hardware or building supply
stores.
On the outside of your house you can conserve water by well-planned
landscaping or xeriscaping, which is landscaping that requires
less irrigation, needs little maintenance and uses sensible
plant materials for the local environment. A couple useful
websites can be found at www.eren.doe.gov/erec/factsheets/landscape.html and www.ces.uga.edu/pubcd/B1073.htm. Rainwater harvesting can
be an outstanding water conserving effort. It’s as simple as
catching rainwater in a barrel via a gutter or a catchment
system with a cistern. Either way, you will catch water from
a spout/gutter/source directed away from the house and use
it on your landscaping where needed.
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to top Local solar businesses/installers
Q: I am interested in installing a solar/photovoltaic (PV)
system on my house. Do you recommend doing that? Do you have
a list
of architects and engineers who specialize in these sorts of
projects?
A: First and foremost, Southface recommends taking all measures
to create an energy efficient home. This is the best bang-for-the-buck.
Once all the efficiency upgrades have been implemented, if
money is still available, installing a solar/(PV) system is
a great way to supplement the energy source that currently
provides electricity to your home. For logical reasons, Southface
does not encourage homeowner to try and go “off the grid” and
provide all their own electricity, but some people do. In addition
to having your own power source back-up that allows you to
have electricity when major power plants may be affected, solar
can also save a homeowner money on power bills. There are other
benefits, which include easing huge environmental impacts associated
with traditional power plants and dependence on foreign oil.
The downfalls, however, include the initial high cost of the
investment, overall maintenance of the system and of course
those cloudy days, which aren’t fruitful for this kind of energy
production. More information can be found at the Department
of Energy website: www.eren.doe.gov. You can find lists of
numerous people and organizations that work with different
types of solar projects on the Southface website: Solar
resources fact sheet at Southface
or www.millionsolarroofs.com.
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to top Funding for solar Q: Are there any financial incentives for using solar systems
on a house or building?
A: As of December 2002, forty-four states currently offer
at least one incentive for solar power. With the exception
of
Maine bundled as a non-incentive state, it is the southeast
region (AL, GA, KY, SC, WV) that does not offer any type of
non-federal incentives for solar power. You can go to www.dsireusa.org to see the various incentive programs that are available in
the state where you reside. Currently, there are no federal
tax incentives involving solar for residential purposes, but
there are two kinds of federally backed loans called Energy
Efficient Mortgages (EEMs) and ENERGYSTAR® Mortgages.
EEMs are broken into two types: new home and existing home.
With an EEM, you can purchase or refinance a home that is already
energy-efficient. Or you can purchase or refinance a home that
will become energy-efficient after energy saving improvements
are made. Most energy-efficient financing programs offer both
types of EEMs, as well as home improvement loans for making
energy efficiency upgrades to your existing home. Additional
information can be located at www.eren.doe.gov/erec/factsheets/feehome.html.
An ENERGYSTAR® mortgage offers a minimum two percent stretch
on a borrower's debt-to-income ratio, plus at least one additional
incentive for borrowers. Incentives may include a lower interest
rate, a discount on closing costs and/or origination fees,
up to a 4 percent extension of the debt-to-income ratio stretch
and paying for the cost of a home energy rating. More information
on this can be found at www.energystar.gov.
www.fannie Mae.com –offers an energy efficiency mortgage
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to top Geothermal Q: What is a geothermal heat pump and what are the advantages
of installing this system to heat and cool my house? Will the
system pay for itself in energy savings?
A: This heating and cooling system relies on plastic pipe
buried below ground where the temperatures are more stable.
Water
or another environment-friendly fluid circulates in the pipe.
In winter, the earth temperature is warmer than air temperature
and the fluid collects heat. In summer, conversely, the temperature
is lower and the fluid is cooled. The piping is connected to
a special type of electric heat pump. On the inside of your
home, a geothermal heat pump delivers heated and cooled air
much like a standard heat pump or furnace and air conditioner.
They can also help circulate hot water. Geothermal heat pumps
are more efficient than standard equipment, so you can expect
to save 25-50 percent on electricity and gas costs. Most experts
say that a homeowner can usually recoup their initial investment
anywhere between two and 10 years. These systems can cost more
to install than typical HVAC, depending on surrounding terrain,
so check with knowledgeable professionals to see if the extra
cost is worthwhile for your home. For more information visit
www.geoexchange.org.
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