 Buildings
of every kind are responsible for 40% of energy flow and 40%
of material use worldwide on a yearly basis. The US Environmental
Protection Agency (EPA) has stated, “Indoor Air Pollution
in residences, offices, schools, and other buildings is widely
recognized as one of the most serious potential environmental
risks to human health.” Remodeling is an opportunity
to make a difference in the world by reducing home energy
use, while providing a healthier interior environment for
you family. Millions of Americans are renovating their homes
every year. Whether because of changing lifestyles or simply
because houses are getting old and out-dated, more money is
spent each year on renovation then on new home construction.
As increasing numbers of people upgrade furnaces, cabinets,
and toilets, their homes can have a positive impact on the
world, creating less fossil fuel pollution, less resource
depletion, and lower health risks. Renovating and reusing
existing buildings may be one of the “greenest”
things we can do.
Installing
solar hot water heaters may not stop greenhouse gas emissions
from reaching what some experts predict will be levels higher
than at any time in the last 50 million years, but it can
help.
 Remodeling
your kitchen with certified sustainable wood will not stop
the annual destruction of an area of biodiversity, old growth
forest equal to the size of Nepal (Time magazine, November
1997, Pg. 13), but it can help.
Installing
energy-efficient, resource-efficient, healthy for occupants,
affordable to create, operate and maintain products when you
do renovation makes a positive difference in your home, and
a contribution towards solving Global Warming through Green
Choices. If more and more people renovating use green remodeling
strategies and products, industry and home owners will play
a significant roll in preserving our limited resources, and
reducing global warming.
Energy
No matter
what kind of remodeling you are doing you should first think
about reducing energy use. Over the past 60 years, our access
to inexpensive energy has allowed building design to ignore
location and orientation. Unfortunately, this trade-off of
historical design wisdom for standardized building comes at
great cost to our environment. We are using our natural resources
at an unsustainable rate. According to Paul Hawken, author
of “The Ecology of Commerce”, today’s population
uses in one day what it took nature 10,000 days to create.”
To say it in another way, we are living on our energy capital
(stored petroleum and coal) and squandering our income (Solar
energy) If you ran your company on your capital savings and
ignored current income, you would not be in business very
long. Green building is a step
toward reversing that trend.
 Based
on 1998 figures, the heating, cooling, and lighting of buildings
consumed 36% of energy in the US. A significant portion of
this energy is in the form of electricity; residential buildings
alone consume 35% of all electricity in the US. However, the
energy that buildings require starts accumulating long before
the buildings and homes are even in existence. The energy
required to extract, transport, manufacture then retransform
materials to the point of use require a substantial amount
of energy at a significant cost to the environment.
The sum
of all the energy required by all the materials and services
(including the cost of upkeep and maintenance) that go into
constructing a building is called the embodied energy. The
unit of measure for embodied energy is British thermal unit
per round (Btu/lb) It is highly dependent on factors such
as geographical location and the technology used during the
manufacturing process. For example, stones excavated from
a nearby hillside for a new patio have lower embodied energy
than stones that must be transported from another state. Embodied
energy figures give us a realistic base for comparison to
assess different products or technologies for use in our homes.
To better
understand embodied energy, let us consider a brick in your
exterior wall. Where did it come from? First, clay had to
be extracted from the earth. Then, it was transported to the
brickworks where the clay was molded into brick form. Then
fired in a kiln. Eventually the brick is transported twice
more- to a retailer and then again direct to your building
site - before the brick was put into your house However, this
is only the direct embodied energy of the brick. Embodied
energy also includes indirect energy, including mining equipment
to extract the clay, trucks to transport the clay, and kilns-
anything that had a proportion of its energy invested in that
brick.
The embodied
energy in recycled buildings materials is generally much less
then the embodied energy in materials produced from raw, or
new, materials. Although using recycled materials can involve
transporting, cleaning, and sorting, the total energy requirements
are still far less than energy used in extracting and refining
a virgin resource.
This section
will help you assess the embodied energy that goes into your
home, the products you use, and the way you live. In this
way, you can understand and appreciate the complexity of construction,
and its profound affect on everything around us. Our goal
is to help you make appropriate choices when planning your
remodeling project.
Effects
of Fossil Fuel on Use
Green
building will help wean us off our dependence on fossil fuels.
Currently, the US relies on fossil fuels(oil, coal, and natural
gas) for 86% of its energy needs, despite their polluting
effects. Burning these fuels spews tons of fine particles
(ulfur dioxide, toxic metals, and other pollutants) into the
air. The Union of Concerned Scientists (USC) estimates that
fine particles alone may cause 64,000 deaths a year, or more
deaths than result from auto accidents. In addition, drilling
for oil, natural gas and mining for coal harms the environment
by polluting natural surroundings and disrupting local wildlife
populations. Given that the building sector is the second
largest user of energy, changes in current building behavior
is critical to reducing fossil fuel emissions and environmental
damage, including the larger international issue of global
climate change.
Using
Less Energy
In addition
to investing in renewable energy sources, as homeowners we
can make simple changes to our homes that save energy- always
the best environmental solution! It is estimated that 43%
of American energy is wasted. The US department of Energy
estimates that we could save anywhere from 50 to 94% of our
home energy consumption by making energy-saving changes in
our homes.
 Green
building reduces energy consumption in many ways. First, we
can decrease the embodied energy of the building through efficient
design, using recycled and local materials, and by recycling
construction waste. Second green building design reduces building
energy consumption over its lifetime.
Installing
ceiling insulation and double glazed windows in every US home
can save more oil then the Artic National Wildlife Refuge
can produce at its most optimistic projections, at about 1/20
the cost. Strategically placing windows and skylights can
eliminate the need for electrical lighting during the day,
which is often when electricity is at highest demand from
utilities. A whole house fan can cool a house over night,
rather then relying on air conditioning. Additionally, houses
can maximize passive heating and cooling. South facing windows
with overhangs can reduce heating costs by 20 to 30 %, and
prevailing breezes, shading, and natural plantings can keep
houses cool in the summer using the same physics that cause
global warming.
This list
only scratches the surface of the possibilities for reducing
building energy requirements. The financial benefits are obvious;
less energy leads to lower energy bill. Additionally, decreasing
energy consumption, and thus reducing alterations in the global
climate, could help prevent further environmental degradation.
Keep in mind it is the impacts of energy use that we are trying
to avoid- not the energy itself. In other words, reducing
use of specific non-renewable, polluting energy sources (for
example, coal or oil), should be a higher priority than increasing
the use of renewable energies such as solar generated electricity.
Use
renewable Sources of Energy
When we
discuss “renewable “we are referring to solar,
wind, geothermal, and bio-mass energy sources.
For building
green, we do not need fossil fuels or nuclear power- we need
services they provide. Most often, we want heating, lighting,
energy, and fuel, and this we can obtain from other renewable
sources- such as wind, sun, biomass. As Amory Lovins, president
of the Rocky Mountain Institute has said for many years. “People
want hot showers and cold beer: they don’t care where
the energy came from.” Renewable energy just needs to
prove better or cheaper.
Solar
energy
 By
far the largest part of the energy on Earth comes from the
sun. The sun gives off so much energy that it is an equivalent
to a 180-watt bulb perpetually burning for every square meter
on earth. This solar energy influx is equivalent to about
7000 times our present global energy consumption. In other
words, there is tremendous potential in solar energy to provide
a significant portion of our heating, lighting, electrical,
and mechanical power needs-7,000 times our energy needs. Just
by covering an area 291x291 miles square with solar cells,
this 0.15 % of the Earths land mass could supply all of our
current energy requirements.
But you
don’t need solar cells to take advantage of the suns
energy for your home. Passive solar heating and cooling represent
an important strategy for displacing traditional energy sources
in buildings. Anyone who has sat by a sunny south facing window
on a winter day has left the effects of passive solar energy.
Passive solar techniques make use of the steady supply of
solar energy by means of building designs that carefully balance
their energy requirements with the buildings site and window
orientation. The term “passive” indicates that
no additional mechanical equipment is used, other than the
normal building elements. All solar gains are brought in through
windows, with some use of fans to distribute heat or effect
cooling.
All passive
techniques use building elements such as windows, walls, floors,
and roofs, in addition to exterior building elements and landscaping,
to control heat generated by solar radiation. Solar heating
designs collect and store thermal energy from direct sunlight.
Passive cooling minimizes the effects of solar radiation through
shading or generating air flows with convection ventilation.
Another
solar concept is day lighting design, which uses natural light
to illuminate rooms during the day and contributes greatly
to energy efficiency by eliminating the need to turn on lights.
The benefits of using passive solar techniques include simplicity,
low price, and the design elegance of fulfilling ones needs
with materials at hand.
 Photovoltaic
(PV) cells convert sunlight into electricity for your home.
They are usually made of silicone; they contain no liquids,
corrosive chemicals or moving parts. Moreover, PV cells require
little maintenance, do not pollute, and operate silently.
Photovoltaic cells come in many sizes, but most are ten centimeters
by ten centimeters , and generate about half a volt of electricity.
A bundle of PV cells that produce higher voltages and increased
power is referred to as a PV module, solar collector, or array.
A module producing 50 watts of power measures approximately
40 centimeters by 100 centimeters. PV modules can be retrofitted
on to a pitched roof above the existing roofing, or the tiles
replaced by specially designed PV roof-tiling systems.
PV modules,
like flashlights or cars, generate direct current (DC), but
most home electric devices require 120-volt alternating current
(AC). A device known as an inverter converts DC to AC current.
Inverters vary in size and in the quality of electricity they
supply. Less expensive inverters are suitable for simple loads,
such as lights and water pumps, but models with good waveform
output are needed to power electronic devices such as TV’s,
stereos, microwave ovens, and computers. In grid connected
systems, PV supplies electricity to the building and any daytime
excess may be exported to the grid. Batteries are not required
because the grid supplies an extra demand. However, if you
want to be independent of the grid supply you will need battery
storage to provide power outside daylight hours.
 Between
1987 and 1998, the annual number of US PV shipments in the
US grew 640 %, with 20.5% average annual increase. The cheapest
photovoltaic cells have become three times as effective since
1978. Back in the 1970’s the cost of PV cells was $70.00
per watt of production; today, residential solar energy system
typically costs about $8 to $10 dollars per watt. In some
areas, government incentive programs, together with lower
prices secured through volume purchases, can bring installed
costs as low as $3 to $4 per watt. Without incentive programs,
solar energy costs (in a average sunny climate) range from
22 to 40 cents per kilowatt hour. Scarcely a month goes by
without another advance in either PV cell design or manufacture
technology. By 2030, the price is expected to drop to 5.1
cents per kilowatt hour. PV demand has been stimulated in
part by government subsidy programs, and by equipment rebate
policies and tax credits for utilities or electricity service
providers. The central driving force, however, comes from
the desire of individuals or companies to obtain their electricity
from a clean, non-polluting renewable source, for which they
are prepared to pay a small premium. The greater the demand
for PV, the faster the price will come down.
PV systems
are appreciate for electric devices, but water heating or
other heating is most efficiently produced by solar water
heaters. They convert up to 60 percent of the suns energy
into heat used for domestic hot water, pool heating, and space
heating needs. There are two types of systems: passive and
forced circulation. A passive water heater consists of a water
tank located above a solar collector. As water in the collector
warms, water flows by natural convection through the collector
to the storage tank. A forced circulation system requires
a pump to move water from the storage tank to the collector.
Most solar water heaters in the US are forced circulation
type.
There
are several types of solar collectors. Most consistent of
a flat copper plate with water tubes attached to the absorber
plate. As solar energy falls on the copper plate and is absorbed,
the energy is transferred to the water flowing in the tubes.
Integral collector and storage systems combine the function
of hot water storage and solar energy collection into one
unit. Solar collectors are typically roof-mounted, with hot
water storage tanks inside the house. They are often connected
to a conventional water heater for back up.
 Solar
water heating systems are efficient, clean, easy to install,
and virtually maintenance free. And since hot water counts
for as much as 40% of the energy requirements of an average
house, solar water heating systems can cut the costs for heating
hot water by 40 to 60%. An active flat plate solar collector
system will cost approximately $2500.00 to $3500.00 installed,
but will have a lower capacity. If the monthly cost of financing
the system is less than the net savings, a solar water heating
system may result in immediate positive cash flow.
Overall,
solar energy has a bright future. Passive heating obviously
makes economic and environmental sense today, and solar systems
are cheaper, simpler, and more reliable than ever for homes.
All types of solar applications are expected to become commonplace
when and if the true costs of fossil fuel use. Including external
costs like pollution, health risks, and military protection
for foreign oil sources-become reflected in its price.
"Life
is good, and getting greener everyday." |
