ENERGY TOOL: SEEKING FUNDING FOR AN ENERGY EFFICIENCY PROJECT?
ENERGY STAR OFFERS THE CASH FLOW OPPORTUNITY CALCULATOR,
WHICH HELPS USERS QUANTIFY PREDICTED SAVINGS AND IDENTIFY
WHEN TO PURCHASE NEW EQUIPMENT.
Inside LED Metrics
➙Planning an LED retrofit? Low energy consumption and a long
life make solid state lighting an
attractive option, but deciphering the
lighting metrics on product packages and
spec sheets can be confusing.
This guide to the most common metrics used by LED vendors will help you
understand what’s behind the ratings.
Lighting Facts Labels
The DOE established the LED Lighting Facts program to ensure one consistent source of information about all LED
products. Lighting Facts labels include
five basic metrics.
Color temperature (CCT): Color
temperature characterizes how “cool”
(blue) or “warm” (yellow) a white
light appears. Ratings are expressed
in Kelvins (K). Lower numbers around
2500-3000K indicate warmer light,
mid-range values of 3500-4000K are
generally considered fairly neutral and
white, and higher temperatures appear
Color Rendering Index (CRI): This
metric indicates how accurately a light
surface renders color as determined by
tests with color samples. The ratings
typically fall into a 0-100 range, with a
standard incandescent lamp achieving
100, though it’s possible to get a negative
score. A source with a CRI in the 70s is
acceptable for interior lighting, according
to the DOE, but a CRI of 80-90 would be
Two light sources that have the same
CCT and CRI may still not render colors
the same way, but the two factors still
serve as a good starting point for evaluating color performance – the real test will
come when you perform your own visual
Lumen output: The quantity of light
that leaves the lamp. The higher the
number, the more light provided.
Watts: Lighting Facts labels also
provide the input wattage of the lamp.
Use it to project energy savings based on
the lighting system you’re replacing with
Efficacy: Expressed in lumens per
watt, the efficacy rating denotes how
much light the product puts out for every
watt of electricity it uses.
In addition to the basics on energy
input, lumen output and color performance, spec sheets offer a wealth of
other information that can help you
make a decision. Consider these metrics
to help you narrow down your product
Useful life: Lifetime ratings represent
approximately how many hours of operation it will take before the LED’s light
output has declined to 70% of the initial
lumens, referred to as lumen maintenance and often abbreviated as L70. The
DOE recommends asking the fixture
manufacturer for test data to support the
life claims on the package.
Expected lumen maintenance: The
calculated L70 value sometimes exceeds
the intended product use cycle or the
lifetime of another lighting system component, the DOE explains. An alternative
method of calculating lumen maintenance performance involves predicting
what the lumen maintenance will be at a
fixed time interval, such as 25,000 hours.
Compiled by Janelle Penny
Evaluation Tool for Community Energy Efficiency
➙Conducting reviews of com- munity-wide energy efficiency
programs and goals will become
easier thanks to a new tool from the
American Council for an Energy Efficient
Economy (ACEEE). The Local Energy
Efficiency Self-Scoring Tool can evaluate
the effectiveness of efficiency programs
in local government initiatives and poli-
cies regarding buildings, utilities and
The tool uses metrics similar to
ACEEE’s City Energy Efficiency Scorecards and can be used to benchmark
current energy efficiency improvement
projects and gain a fresh perspective
when new policies are implemented.
The tool will also allow users to
submit results to ACEEE, which plans
to publish a collection of best practices
and innovative ideas that communities
are using to cut back energy usage. Much
of the information required to complete
the tool is readily available, such as the
Building Codes Assistance Project, but
for some metrics community leaders will
be encouraged to conduct “community
research” whenever no existing data
source directly addresses the metrics.
As part of the launch, ACEEE has
scored eight localities for comparison
purposes, with population sizes from
under 10,000 people to nearly 250,000.
Seven Excel worksheets comprise the
tool, including five that address specific
policy areas: buildings, local government
operations, transportation, energy and
water utilities and community-wide initiatives. The tool is compatible with all
versions of Microsoft Excel and can be
used on either a PC or a Mac computer.
A NEW COMMUNI TY BENCHMARKING TOOL
evaluates the effectiveness of municipal
initiatives on buildings, utilities and
transportation. How does your city rank?