| Energy
Myths
by Evan Mills, Lawrence Berkeley National Laboratory
staff scientist
Energy and energy savings myths get
passed around surprisingly rapidly, often with little scrutiny.
But an examination of 13 common myths reveals that they should
be treated with some healthy skepticism. Sometimes the basic
premise of the myth is correct, but the energy savings are
much smaller than people realize. In other cases, the myth
is based on factors that were once true but have been subsequently
resolved through better design or manufacturing of products.
In all cases, the bottom line is that you should always think
critically when you hear a "tip" on how to save
energyand dig a little deeper to separate the myths
from the facts.
Myth: Buying an efficient
air conditioner or furnace will automatically reduce my energy
bill.
This is true to some extent, but you won't realize
all the possible savings if the equipment is not
sized or installed properly. Studies have shown
that typical air conditioner and duct systems
are improperly installed, wasting one-third or
more of the energy used by the air conditioner.
New and replacement equipment (and ducts) need
to be properly designed and installed to realize
all the possible savings. The same caveats about
proper installation hold true for insulation,
windows, and many other energy efficiency upgrades.
Myth: Energy
efficiency and energy conservation are one and the same thing.
Well-intentioned information campaigns during the oil crises
of the 1970s created a lot of confusion about how to save
energy and even about how to talk about saving energy. Energy
efficiency means getting the same job done while using less
energy. This could be lighting a room, cooling a house, or
refrigerating some vegetables. The things made possible by
using energysuch as illumination, comfort, or food preservation--are
sometimes called energy services.
Energy conservation, on the other hand, means
reducing the level of services, such as reducing
lighting or comfort, or turning up the temperature
of your fridge. Reducing service levels (conservation)
does not necessarily mean sacrifice, however.
For example, many spaces are overlit by current-day
standards, many water heater temperatures are
set too high, and so on. Consumers have the option
of improving energy efficiency (such as through
purchasing better appliances) and/or reducing
service levels, but lowering the quality of life
is not a prerequisite for reducing energy demand.
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Myth: Duct
tape is good for sealing ducts.
Unfortunately,
laboratory research has concluded that duct tape has
very low durability when used to seal ducts. On new
installations, tape often falls off due to poor surface
preparation, because ducts tend to be installed in dirty
and dusty locations and conditions. On older systems,
the tape falls off as it ages and the adhesive dries
out and wrinkles. Instead of duct tape, seal ducts with
mastic.
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| Myth:
When my appliance is turned off, it's off.
We've
found that most devices continue to consume power when
they're switched off, sometimes as much power as when
they're on! A surprisingly large number of electrical
products--from air conditioners to VCRs--cannot be switched
completely off without unplugging the device. These
products draw power 24 hours a day, often without the
knowledge of the consumer. We call this power consumption
standby power. One easy remedy for this is to unplug
appliances when you are out of the houseeasily
done if many items are grouped together on one power
strip.
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Myth: Cleaning
refrigerator coils saves energy.
While
this seems intuitively logical, and very small savings
may indeed arise, efforts to actually measure this effect
have typically come up empty-handed. Cleaning coils
is probably a good idea, especially if you want to cut
down on dust and dirt buildup in your kitchen, but dont
expect lower utility bills from it.
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| Myth: Installing
foam gaskets in electrical outlets will significantly
reduce air leakage.
Measurements
have shown that less than 1% of a home's air leakage
is due to outlets. However, a lot of little holes add
up to one big hole. If youre doing a thorough
air sealing job, or youre in a very big house
with a lot of light switches, it wouldnt hurt
to install gaskets--but you might want to save this
measure for last, in case you run out of time or energy.
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Myth: Leaving
lights, computers, and other appliances on uses less energy
than turning them off and on repeatedly, and makes them
last longer.
The
small surge of power created when some devices are turned
on is vastly smaller than the energy used by running
the device when it's not needed. While it used to be
the case that cycling appliances and lighting on and
off significantly reduced their useful lifetimes, these
problems have been largely overcome through better design.
The rule of thumb today is: Turn off the lights when
you leave the room, and use the power-management software
that comes with your computer and monitor.
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| Myth: Energy
efficiency increases the first cost of houses.
While
efficient products usually cost more, in some cases
there may be little or no added initial cost. Most efficient
products are also premium products (in terms of features,
warranty, and so on), so it's difficult to say that
you are paying for the efficiency. In some instances,
efficiency can even reduce first cost, as in the case
where smaller, properly sized heating and cooling systems
can be installed if they're highly efficient. When homes
are designed well and include such measures as passive
solar lighting and heating measures, optimum-value engineering,
correctly sized HVAC systems, high-tech windows, and
shorter duct runs, up-front building costs often turn
out to be about the same as those of conventional homes,
while operating costs are significantly lower. Whats
more, high-performance homes offer huge savings in terms
of occupant comfort and safety, and reduced litigation
and callbacks.
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Myth:
Insulating the ceiling will just cause more heat to leak
out of the windows.
Adding
insulation to one part of a home won't increase the
"pressure" on heat losses through other parts. However,
it is true that poorly insulated areas will be the major
losers of heat, and that they often merit attention
before improving already well-insulated parts of the
home. To best insulate a home, large and small leaks
must be addressed.
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| Myth: Switching
to electric room heaters will reduce your energy bill.
This
is true only under some circumstances. If you have central
electric heating, using individual room heaters may
save you money, if you just run the heater in the room
that you occupy. But if you have central gas heating
(which is typically cheaper per unit of useful heat),
you can easily match or even exceed your heating bill
by switching to electrical units.
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Myth: Fluorescent
lighting is unhealthy.
Fluorescent
lighting has changed dramatically in the last few years.
Today's fluorescents have greatly improved color quality.
And the annoying flicker and hum have been eliminated
from fluorescents that use electronic incandescent lighting.
Because they require less electricity, fluorescents
generate less power plant pollution, which has many
known health effects. Fluorescent lights do contain
small amounts of mercury and must be disposed of properly.
However, additional mercury releases are avoided thanks
to reduced use of mercury-containing fossil fuels used
to generate electricity. If it's been a while since
you tried fluorescent lights, you might give them another
chance. The oft sited claim of fluorescent lights "sapping
people's vitamins" and the like have no basis in
fact.
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| Myth: Halogen
lighting is superefficient.
It's
true that halogen lights use slightly less energy than
standard incandescent bulbs, but many halogens require
transformers that can use extra energy, even when the
light is off. They also tend to put off a great deal
of heat, which may add to the cooling load of a home
during hot weather. Halogens can also pose a serious
fire hazard. By comparison, compact fluorescent lights
are nearly three times as efficient and put off far
less heat. Many new models are dimmable, like halogens.
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Myth: Electric
heating is more efficient than fuel-based heating.
It's
true that all, or almost all, of the electricity that
goes into an electric heater is transformed to useful
heat in your home. However, making electricity is an
inefficient process, with as much as two-thirds of the
input energy (coal, natural gas, and so on) being lost
in the process. This is why electricity is typically
so much more expensive for the consumer than direct
fuels. Dont forget, though, that combustion appliances
in the home must be installed and vented properly and
must always have a continuous, reliable source of makeup
air.
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Reprinted with permission from the Lawrence
Berkeley National Laboratory Web site (http://homeenergysaver.lbl.gov/hes/myths.html).
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