Think You’ve Achieved Maximum Lighting Performance and
Efficiency with Your Fluorescent Upgrade? Think Again.
In the quest to save energy, many facility managers have replaced aging HID, HPS and T12 lighting with high-output
T5 or T8 fluorescent (HIF) fixtures. These retrofits saved energy compared to legacy lighting, but the savings that were
impressive at installation time are now eclipsed by the superior energy savings potential offered by intelligent LED systems.
By combining a low-wattage, highly controllable illumination source with sensing, integrated controls, and wireless
networking, these high-performance LED lighting systems now effectively replace HIF lamps, and still save up to 90%
on lighting energy.
Intelligent LED lighting systems leverage the power and flexibility of LEDs as an illumination source and take a more
sophisticated, network-based approach to lighting. They eliminate the shortcomings of HIFs and offer facility managers
the opportunity to approach lighting as a strategic asset — all without performance issues, lengthy warm-up times,
and ongoing maintenance (re-lamping/re-ballasting) chores.
While it seems unconventional to replace HIFs with LEDs, especially if the HIF installation was relatively recent,
the case for evaluating the decision involves performance and economic considerations. This white paper explores:
• How intelligent LED systems harness new levels of control to maximize energy savings,
• The economic considerations of an upgrade from HIF to an intelligent LED system, and
• Case studies of facilities that have made the switch.
REQUIREMENTS FOR MAXIMUM LIGHTING EFFICIENCY
Maximizing lighting efficiency means managing the variables that affect lighting use, and requires a comprehensive
LED-based lighting system that supports:
• Rapid on/off cycling without warm-up times or diminished lifetime.
• Full-range dimming, from 0-100%.
• Occupancy and daylight harvesting sensors integrated into every fixture.
• Application-specific optics — narrow/aisle/wide — to place light where it is needed without the need for
reflectors or over-lighting.
• Adjustable light bars — combined with application-specific optics — to enable optimal distribution of light.
• Short time-out settings to minimize the amount of time a fixture is left on after an area is vacated.
• Scheduled settings that manage lighting according to differing cell or shift needs, operating hours or
seasonal changes, among others.
• Distributed intelligence that ensures that each fixture in the network is able to store its instruction set,
for consistent and safe operation at all times.
• Centralized control that eliminates the need to touch a lighting fixture to change settings.
• Integrated data gathering with metering, such as kWh used, occupancy patterns, and kWh saved from
daylight harvesting.
• Wireless networking for data sharing and ease of deployment.
• Detailed reporting by fixture, zone or facility-wide to enable learning and fine-tuning.
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Think Again.
These capabilities, combined, offer the performance and efficiency that creates bottom-line impact. Without this
functionality — all integrated — true efficiency will remain elusive. And therein lies the problem for HIF fixtures.
Even the latest generations can’t achieve the performance, efficiency, or functionality that intelligent LEDs offer facilities
seeking dramatic energy savings. In fact, fluorescents can’t match LEDs’:
• Efficiency on a pure wattage basis. Every moment a fluorescent fixture is on, it uses more energy than an LEDbased fixture to deliver necessary illumination levels. And fluorescents are often left on — either completely or
partially — to avoid warm-up issues with restrike.
• Tolerance for rapid on/off cycling (e.g. anything less than 15-minute intervals), without warm-up times, degradation
of light output, or negative impacts on ballast/lamp life. Unlike fluorescents, LEDs are maintenance-free, perform
well in all temperature environments and do not degrade with frequent or rapid cycling. In fact, the more LEDs
are off, the longer their lifetime.
• Ability to rapidly respond to sensor inputs (occupancy, daylight). Dramatic energy savings are driven by
integrated occupancy and daylight sensors built into every intelligent LED fixture, allowing the fixtures to instantly
respond to environmental activity. In contrast, HIF sensors are often installed circuit-wide (with settings fixed at
installation), which compromises performance and erodes energy savings. When combined with the lack of on/off
cycling tolerance, circuit-based sensors applied to a difficult-to-control technology do not deliver the energy savings
that offset the cost of the aftermarket sensor package.
• Inherent controllability that, when coupled with lighting management and control software, enables facility
managers to continuously fine-tune system settings and behaviors. This level of functionality simply does not exist
among the fluorescent alternatives, and is unlikely to be developed due underlying technical limitations.
• Ability to place light exactly where needed through a variety of optic choices, ranging from narrow to wide
and aisle, and light bar rotation. Instead, HIF lamps have a ‘one-size-fits-all’ optics approach that forces facilities
to over-light space to ensure adequate light levels due to optics or lumen depreciation issues. The results are a
tremendous amount of unused light, work surface glare, and higher energy costs.
Worth noting is that plain LEDs, alone, do not deliver energy savings beyond simple one-time wattage reduction. LEDs
need to be part of a comprehensive system that integrates system-wide intelligence to achieve maximum efficiency.
Leading industrial facilities are proving that it is possible to leverage intelligent systems to cost-effectively transition
from HIF to intelligent LEDs and save as much as 90% of lighting energy costs. How? By eliminating unnecessary light
and taking a more strategic approach to lighting.
THE PILLARS OF ENERGY EFFICIENT LIGHTING
Facility managers are well-versed in the drivers of lighting energy use — fixture wattage, dimming, occupancy, daylight
harvesting, facility operating hours, and light level requirements — but have been constrained by traditional lighting
sources’ inability to be managed around those variables, while ensuring safe light levels. HIF lighting has offered
incremental advances, e.g., step-level dimming, circuit-level controls, or even individual sensors, but intelligent LED
systems deliver far greater benefits. Compare intelligent LED systems and HIF fixtures with respect to energy-efficiency
and energy-savings opportunities:
Wattage
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Digital Lumens
The first step towards energy reduction is wattage reduction, where LEDs outshine HIFs
by a wide margin. A typical 4LT5 HIF fixture consumes approximately 234 watts, a 6LT5
uses approximately 330 watts, while a 18,000 lumen intelligent LED averages 215 watts
and offers higher quality light. The differences represent significant savings opportunities
that are locked-in for the lifetime of the installation.
Think Again.
Occupancy
Occupancy — how much a space is used and requires lighting — is a major factor in lighting
energy efficiency and varies dramatically by industrial facility, running the gamut from 10%
in some cold storage environments to 50-70% in manufacturing facilities. By turning off
or dimming lighting when a space is vacated, facilities lock in significant energy savings.
Facilities using intelligent LEDs are accumulating these savings, whereas facilities with
fluorescents — which are generally left on 100% of the time during operating hours — are
spending money unnecessarily.
Dimming/Task Tuning To achieve high levels of energy efficiency, the ability to dim lighting and manage dimming
settings is an absolute requirement and a key driver of savings. It provides facility managers
with the ability to closely align light output with the specific needs of a particular task or
workspace, especially as those change over time. Dimming also makes it cost effective to
provide background and/or security lighting in cases where full light is not needed, such as in
unoccupied spaces during off hours.
The numerous limitations associated with dimming fluorescents — from cycling, lamp
longevity and ballast issues to controllability — preclude many facilities from actively using
these capabilities. In fact, dimming is frequently disabled within facilities that have installed
dimmable fluorescents, and/or lamps that are almost always on, negating the value of the
initial investment.
Daylight Harvesting
Natural light — from skylights, windows and open bay doors — is a gold mine of energy
savings and frequently accounts for 30-50% of a facility’s energy savings during daylight hours.
Intelligent LEDs with integrated daylight sensors continually assess available ambient light
and smoothly dim or turn off lighting as needed to maintain a facility’s illumination target.
The key factors in successful daylighting are dimming, granular daylight sensing, and fixture
behavior. LEDs are far better suited to dimming than HIF because HIF dimming is fairly
limited. Additionally, HIF daylighting sensors are typically installed on a circuit basis, which
means that an entire group of fixtures — some near the natural light source, some far —
are responding to the single sensor input. Since the amount of natural light decreases as
you move away from the light source, any solution that does not build daylight sensors
into every fixture, is by definition using too much energy to ensure optimum light levels
or, alternatively, inadvertently under lighting around fixtures that are responding to sensor
input from a far-away fixture. Every intelligent LED fixture integrates occupancy and
daylight harvesting sensors to ensure proper light levels across the facility.
Timeout settings' impact on energy costs.
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Think Again.
Timeout Settings Intelligent LEDs compound occupancy savings with the ability to use short timeout settings
— the amount of time a fixture stays on once a space is vacated. In contrast, HIF ballast
warranties are often invalid if timeout settings are set for increments of fewer than 15 minutes.
And, as previously mentioned, even these long timeout settings on HIF fixtures are frequently
disabled, or the settings are just long enough that the lights never actually go out. The table
below shows the substantial impact timeout settings have on energy use/costs.
Programmed Settings Lighting needs often change — by time of day, week or year. Or, in the case of manufacturing
facilities, lights may need to be re-grouped into different operating cells. Note: Their position
on the ceiling doesn’t change, but their settings change when the cell is reconfigured.
Intelligent LED systems enable facility managers to change all lighting variables to support the
business’ needs. They can establish lighting settings to match the facility’s business schedule,
which will automatically modify light levels to meet varying lighting needs — operational
shifts versus cleaning and maintenance, for example, or regular versus holiday schedules.
Data/Fine Tuning
Side-by-side
Comparison
Measurement and verification is a critically important efficiency tool, as it eliminates all
the guesswork from the lighting optimization equation. Intelligent LEDs provide — on a
fixture-by-fixture, zone or facility-wide basis — detailed performance metrics on how a
system is performing, such as kWh used, workspace occupancy patterns and energy costs.
This actionable intelligence enables facility managers to update system settings to optimize
lighting delivery and savings, without compromising safety, productivity or comfort.
6-Lamp T5
Intelligent LED System
Wattage
331W
13K lumen - 155W or
18K lumen - 215W
Dimming
Limited/Step-level
Digital (0-100%)
Daylight Harvesting
Circuit
Every fixture
Occupancy
Circuit
Every fixture
Limited Manual
Extensive (:30 and up)
Scheduling
Add-on
Yes
Data/Fine Tuning
Add-on
Yes
Timeout Settings
ADDITIONAL CONSIDERATIONS
More efficient lamp sources save energy, but truly extraordinary energy savings can only be achieved by turning off,
or dimming lighting to eliminate unnecessary light, e.g., when a workspace is unoccupied or when natural daylight is
present. Yet rapidly cycling fluorescent fixtures results in a host of problems that increase the cost of owning and
maintaining these fixtures, including:
Lamp Life
Frequent on/off cycling significantly shortens the life of a fluorescent fixture, so much so that
most fixture manufacturers include language voiding their warranties if a fixture is cycled too
frequently. Usually stated in terms of minimum burn times per cycle, this is because every
time a fluorescent light is cycled on, a part of the electrode coating is burned off, which
shortens lamp life. Worth noting is that HIF lifetime ratings are based on MTBF (mean time
before failure, or a 50% failure rate), vs. LEDs, which use the L70 lifetime rating.
Since average life ratings for fluorescent lamps are based on a 3-hour burn cycle — meaning
the lamp is cycled on only once every three hours during ratings tests — shorter cycle
times mean fixtures need to be re-lamped more often than their average life ratings suggest.
This is a costly undertaking for facilities with hundreds of multi-lamp fixtures and 24 x 7
operating schedules.
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Digital Lumens
Think Again.
There is no known way to “fix” the fluorescent cycling issue and its impact on lamp life; it
is inherent to the underlying technology.
Note: Digital Lumens offers a dedicated paper on LED lifetimes, “Gauging the Lifetime of an LED,”
that offers in-depth information on LED lifetime standards.
Ballast Longevity Like fluorescent lamps, ballasts wear out faster with increased cycling, so the more a fixture is
cycled, the shorter the ballast life. This means that the more facility managers try to increase
energy efficiency by turning off unnecessary HIF lighting, the more they face the costs and
disruptions associated with re-ballasting. This is a cruel irony for facility managers focused
on energy efficiency.
Of the three available ballasts, the most commonly used are instant and rapid start, neither
of which was designed to support frequent cycling. Accordingly, these ballasts generally
experience 25% to 50% shorter lifetimes when used with sensors that cycle lights on and off
based on occupancy. For this reason, they are not usually recommended for cycling applications.
The third type of fluorescent ballast, programmed-start, is considerably more expensive
than instant and rapid start ballasts, but offer the highest number of starts before failure.
Programmed-start ballasts pre-heat the cathodes before applying voltage to the lamps, easing
start-up and its impact on lamp life and ballast longevity. While this lengthens re-ballasting
cycles, it does not eliminate them, and replacement ballasts are expensive, both in materials
and staff time. Furthermore, programmed-start ballasts consume more energy than instant
start ballasts and, more importantly, hesitate for several seconds before returning to full
on when needed.
Maintenance &
Hazardous Material
Disposal Costs Most facilities acknowledge that the cost of re-lamping and re-ballasting fluorescent fixtures
is significantly higher than the cost of replacement parts alone. Manpower, workplace disruptions
and equipment rentals (e.g. scissor lifts) easily double or triple the costs associated with the
re-lamping and re-ballasting exercise, as do the hazardous material disposal costs associated
with these mercury-based lamps.
An equally important issue is determining the source of a fixture failure (e.g. Is it the lamp,
the ballast or an add-on sensor?) and which manufacturer’s warranty will cover the failure.
Currently, most facilities serially replace parts, starting with all the lamps, until the fixture
is operating again. This is a costly and resource-intensive endeavor only minimally covered
by the failed part warranty.
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Think Again.
ECONOMIC CONSIDERATIONS: HIF TO INTELLIGENT LED SYSTEMS
Financial considerations of any system upgrade always travel hand-in-glove with the performance criteria, and lighting
is no exception. This is particularly true when considering an upgrade to an investment that may have been recently
made, such as HIF. The economic analysis for these projects is slightly different than considering two new-purchase
alternatives side-by-side. In this case, you’re evaluating whether to continue with the same lighting you have in place or
invest in an intelligent LED System. The financial analysis should start with a Total Cost of Ownership (TCO) assessment
that includes:
•
Credible energy use and energy cost estimates of the HIF fixtures compared to Intelligent LEDs, based on
facility operating hours, required light levels, fixture wattage, expected occupancy levels, expected daylight
harvesting savings, and any refrigeration load reduction,
•
Calculated utility project incentive (if applicable),
•
Deductions equal to the semi-annual cost of re-lamping and re-ballasting the HIF fixtures
•
EPAct credit (if applicable)
•
Abandonment credit (if applicable)
When taken together, the financial picture for an upgrade from HIF to an intelligent LED system often has an impressive
TCO and compelling payback period. And the best time to consider the transition is when facing a major re-lamping
and re-ballasting exercise, so the expected costs of that project can ‘buy down’ the purchase price of the LED system.
Here’s a side-by-side comparison of the energy and maintenance costs of HIF and intelligent LED alternatives:
100 f ixtures
6-Lamp T5
18K Lumen
Intelligent LEDs
kWh use
289,956 kWh
32,020 kWh
$28,996
$3,202
Annual Energy *
Annual Maintenance
**
Annual Energy & Maintenance
$30,996
$3,202
Year 2
$61,991
$6,404
Year 5
*
Digital Lumens
$0
$3,202
Year 1
Energy &
Maintenance Year 3
Costs
Year 4
6
$2,000
$30,996
$92,978
$9,606
$123,982
$12,808
$154,978
$16,010
Assumes 20% occupancy, 15% daylight factor and $.10 kWh
**
$20/f ixture for HIF re-lamping & re-ballasting
Think Again.
CASE STUDIES
Here are snapshots of recent HIF to Intelligent LED Lighting System upgrades projects:
74% ENERGY SAVINGS - Atlas Box & Crating
• 224,000 square-foot manufacturing and storage facility
• Previous lighting: T5HO
• 24x7 operations
• Timeout and dimming settings vary by space
• Reduced lighting energy use by 74%
• 12.6 month payback
85% ENERGY SAVINGS - Associated Grocers of New England
• 380,000 square foot distribution center, with docking, dry goods, cold storage, maintenance and salvage areas
• Previous lighting: T5HO
• 24x6 operations
• Timeout and dimming settings vary by space
• Reduced lighting energy by 85%
• 1-year payback
91% ENERGY SAVINGS - DiloSpinnbau
• 71,000 square foot manufacturing facility
• Previous lighting: T5HO
• 40 hours per week
• Dramatically improved light levels (from 14-18 foot candles to 41 foot candles)
• Reduced lighting energy by 91%, 35% savings from daylight harvesting
• 2.6 year payback (w/o incentive)
INTELLIGENT LED LIGHTING SYSTEMS: THE LOGICAL CONCLUSION
Industrial facilities are rapidly migrating to intelligent LED systems, arguably faster than other segments of the lighting
market. The reason is simple. Industrial facilities have greater lighting energy pain, driven by long operating hours, highwattage lighting, and high light-level requirements, and have found that LEDs deliver significant efficiency gains. But
most facilities with HIF fixtures have not considered that the upgrade economics would make a project viable. Time
to think again.
Intelligent LED systems accelerate the efficiency advantage, reaching up to 90% energy savings, while eliminating
maintenance costs and providing visibility and control not found in other solutions. These factors all add up to an excellent
opportunity for all industrial facilities — even those with recently installed HIFs that are about to require re-lamping
and/or re-ballasting — to make the move, and lock in a future of low energy costs and no maintenance.
Digital Lumens
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HIF White Paper
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All Rights Reserved © 2013
Digital Lumens Incorporated
Subject to change without notice.
DOC-000162-00 Rev A 08-13