Energy
Efficiency | Healthy Homes |
Services Green Building Basics: Special Report
(V-2.5) By: Bion D. Howard (Reviewed: Nov. 2007)
B.E.S.T. recommends setting the following
general "green building" goals that can be applied to redesign virtually any
construction project if you get into the process early enough. While these
recommendations pertain largely to residential construction, much of the
information is also applicable to light-commercial construction. Note: these
recommendations are not to be used as design standards, and for best
performance of environmental building strategies we recommend professional
technical support for most projects.
The following measures have been found in
most cases to increase construction costs by less than 10%. Your resulting
project will be comfortable, more durable, healthy to live in, less costly to
operate while helping protect our environment. Obviously there are more details
to a true "environmental building" project but this listing will help get you
started.
Basic Guidelines --
Environmental Building Design and Construction
- Consider building/home sites located
nearer the workplace and essential services, or at least near public
transportation to reduce expense and environmental burden of commuting by
single-occupancy vehicles. [Buying an "affordable" home in a remote
location promotes sprawl and may actually be less economically viable
over its useful life when you include commuting costs].
- Can you deconstruct or refurbish an
existing home/office or school rather than building a totally new structure for
the same end result? Start by understanding the condition and location of an
existing building or site before demolition is elected. [Lessens overall
impact of development by reuse of "embodied energy"].
- Select / layout building site with
emphasis on good drainage, no known in-ground pollutants, and to promote useful
solar access. [no cost].
- Create an energy-efficient thermal
envelope with appropriate insulation for your climate; using a whole-systems
approach. For most parts of the U. S. the Department of Energy recommends at
least R-38 for ceilings, R-21 walls, R-10+ foundations, and insulated doors.
Coordinate this task with window selection. [R-factor is a measure of
resistance of materials to heat flow, higher numbers ~ less heat
flow].
- Design moisture "forgiving" walls and
roof details that repel rain and can dry out (1).
- Demand air-sealed construction with
mechanical ventilation [cheap insurance against poor comfort and mold
problems] Who says "Build it tight, ventilate right"? An excellent source
is EEBA ! (1).
- Select the most appropriate window system
for your climate to complement the homes insulation package; sometimes very
efficient windows can lower the first costs of insulating a home [ask
builder, or their energy consultant, to see the
calculations].
- Design for 35% - 40% passive solar
heating with minimal A/C penalty [computer analysis recommended]
(2).
- Layout the windows, glazed doors, and
skylighting to encourage daylighting of most rooms [no cost]
(2).
- Specify and install high-performance
mechanical equipment and distribution [heating and AC, and hot water supply]
- "Right size" mechanical equipment;
require system analysis by contractor -- reduced system size from other
efficiency often pays for the upgrade to better heating and A/C performance
[can save on first cost, in most cases].
- Locate all forced-air ducts inside the
conditioned spaces [minimal cost - up-front design decision].
- Air ducts for heating and cooling must be
well sealed (1) with Mastic; testing is preferred for best performance of
forced-air systems [minimal cost - job-site
supervision].
- Consider digital thermostat (or EMCS) to
control each zone of the building [inexpensive, can save up to 12% on
heating and cooling costs].
- Consider solar hot water system with a
heat recovery device, [may yield ~ 60%+ efficiency]; avoid low cost but
expensive and pollution-intensive direct electric water
heating.
- Install ceiling fans in major rooms
[low-cost means to improve comfort; air flow allows seasonally higher or
lower thermostat settings to feel comfortable].
- Forget the "fireplace," select an
air-tight woodstove with outside air supply [alt. Built in "Masonry heater"
specifically designed to save energy].
- Install most efficient
EnergyStar™branded major appliances [refrigerator,
clothes washer, dish washer] (3).
- Select a high-performance electric
lighting package. [hard wire fluorescent fixtures in main rooms, avoid too
many ceiling "cans" that add to air leakage; occupancy sensors in utility
areas, stairwells and closets].
- Specify low/no VOC emission building
products [adhesives, sealer, paint, cabinets, etc., should not produce much
"off-gassing" of harmful or irritating chemicals] (4).
- Utilize at least 50% documented
"sustainable" wood products, preferably from 250 mi. radius of building site
(4).
- Install Radon-gas preventive foundation
design [EPA or local health dept. guidance].
- Employ water conservation considering:
tap flow controls, 1.2 gpf dual-mode toilets; or composting toilets [can you
get by with one or one and 1/2 bathrooms?] consider omitting exterior wall
hose-bibs; and instead install greywater recovery system for drip-watering
landscaping.
- Finish with light color exterior finishes
and high-reflectance roof covering [little added cost for lighter
colors].
- Plant (or "land-bank" on site during
grading) native trees near buildings for shading, consider Xeric landscape
species that require less watering; reduce overall areas of lawn [less need
for fertilizers, weed-control and irrigation].
- Install driveways and walks using
moisture pervious surfaces, avoiding impermeable asphalt [which is basically
oil mixed with pebbles; also dark surfaces add to "heat-island" effects].
If concrete is used, ensure it is additive free and mixed to provide a light
color finish. Concrete with high levels of fly-ash waste added to it may be
available in your area, so check with suppliers.
References
- EEBA "Builder Guide" (enter bookstore, select your climate), 1998-2000
http://www.eeba.org
- NREL "Energy-10" computer software,
training and manual http://www.sbicouncil.org
- ACEEE "Consumer Guide to Home Energy
Savings, 7th Edition." 2000 [http://aceee.org/consumerguide/mostenef.htm
- Environmental Building News - "Product
Directory" http://www.buildinggreen.com
Designing and building the above home
should meet or exceed Energy Star Homes and the
US GBC LEED for Homes
"Certified" level when issued.
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Note: This material was developed in support of the US DOE
sponsored SBIC national "Green Building Guidelines" (GBG) project. Bion Howard
is an accredited workshop trainer for GBG and helped develop the publication.
More information on the GBG, and additional sustainable design information and
training opportunities, is available from:
http://www.sbicouncil.org |
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