Energy efficient lighting for warehouses
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This article provides important information on the energy
efficient lighting options for a warehouse building. These can save up to 80%
energy in comparison to older high bay & low bay lights.
If you are considering installing energy saving lighting in a
warehouse building then please go here
to get started now! |
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What does this article cover?
This article covers the energy wastage & operational
problems with outdated warehouse lighting, details of new (T5 fluorescent,
induction lamps & LED) warehouse light fixtures and the many reasons to
upgrade your warehouse lighting. |
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Part 1 - Introduction to warehouse lighting |
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The large, open spaces of a warehouse building or
distribution centre require adequate illumination so items can be identified and
workers can navigate through aisles easily, reducing the risk of accidents and
damage to stored items. As a result, lighting may account for
50%-80% of onsite electric bills for warehouse storage and
logistics facilities.
However, by installing a new energy efficient warehouse lighting system it is
possible to make electricity savings up to 80% without
compromising on working light levels. This is because a large amount of energy
is wasted with existing warehouse lighting system by:
- Using outdated & inefficient lamps and/or light fixtures
- Using lighting at full illumination in warehouse areas where/when not
required
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Part 2 - Outdated warehouse lighting |
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An older warehouse building lighting system will typically
consist of several "high bay" or "low bay" lighting fixtures that use high
intensity discharge (HID) bulbs - rated at 250 Watts or 400 Watts. These HID
bulbs could be either high-pressure sodium ( a peachy-yellow coloured light) or
metal halide (a white-bluish light); with the fixtures mounted 5 metres or
higher from ground level. Older fluorescent strip lamp fixtures (using T8 or T12
tubes) will be more common at lower mounting levels.
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HPS sodium |
Metal Halide |
T8 or T12 tubes |
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A warehouse lighting system that uses outdated light
fixtures will be inefficient due to a combination of the following
factors:
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"Hidden" energy consumption - Older HID
light fixtures that use 400 Watt rated bulbs actually consume between 420-480
Watts due to the extra energy requirement for the magnetic control ballast.
This means an extra 5-20% of energy is consumed (the
same for 250 Watt bulbs)
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Light 'loss' in older
fixtures - Older lighting fixtures may be very inefficient at directing
light where it is needed (e.g. due to a poorly performing reflector) and thus
preventing large levels of illumination reaching working surfaces. This means there may be more fixtures than required to
acheive the required lighting levels
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Using lighting when not
required - The lighting in a warehouse may have default setting of full
power in all areas & aisles during the working day - or even a default 24
hour setting regardless of working shifts. This
means energy is being wasted needlessly
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Using lights constantly at
full power setting - Older HID and fluorescent lighting fixtures cannot
be dimmed or switched in response to area occupancy or the presence of daylight.
This means a large energy saving opportunity is
being missed. |
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When the losses are added up, the annual energy wastage from
an older warehouse lighting system can run into tens of thousands of pounds per
year (the exact amount will depend on operating hours and the unit price paid
for electricity).
The latest warehouse lighting systems address the above
issues and make it possible to acheive an 80% energy saving.
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Part 3 - New warehouse lighting technologies
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Modern warehouse warehouse lighting systems use the latest
efficient light sources (including T5 fluorescent tube, induction lamp &
LEDs) and intelligent control systems. These cut the energy use of older HID or
fluorescent lights by up to 80% while still improving on the existing quality
of light. |
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An overview of T5, induction & LED warehouse light fixtures is
shown below
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T5 fluorescent tube fixtures - These
fixtures use 2, 4 or 6 T5 tubes mounted in a fixture with a polished reflector
to direct all light downwards. The T5 tubes work on the same basic principle as
older T8 & T12 tubes but with an electronic control ballast and a longer
operational life of 12000-18000 hours. Some
advantages include - a well established energy efficient technology, modest
installation cost, the light fixture still produces acceptable light levels
after expiry of a single T5 tube
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Induction lamp fixtures
- These fixtures use induction lamp technology - this works on the same
operational principles as T5 tubes (exciting gas in a glass tube to emit light).
The key difference is not using an electrode to pass a current through the tube
but create an electromagnetic field around the tube. The advantages of induction are a very long operational
lamp life (100000 hours) and high quality white light!
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LED lighting fixtures
- These fixtures use a mounted cluster of high output Light Emitting
Diode components that produce light when an electric current is passed through
them. This solid state technology has a very big future in business lighting as
performance continues to improve and cost is reduced. Some advantages include long lifetime (50000-100000 hours) and a
unidirectional light source, eliminating any need for
reflectors. |
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The new warehouse lighting systems
So there is a set amount of energy saving in swapping over
the fixture and then an additional saving achieved from the lighting control
system. The next section covers this in more detail. The three energy efficient
warehouse lighting options (T5 fluorescent tube, induction lamp & LEDs) have
the ability to be dimmed and switched instantly - this allows very effective
energy saving control systems to be
designed |
Part 4 - Warehouse lighting control systems
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It is not uncommon for a warehouse lighting control system to
be an absolute minimum - a default on setting for all lights, only deactivated
during non-work periods.
An effective warehouse lighting control system should switch
off or dim the output of the lamps automatically when full illumination is not
required. However, older warehouse lights cannot provide instantaneous full
light output - HID lamps with magnetic ballasts have a ‘warm-up’ time (to reach
90% of full output) and an extended re-strike time (time needed for lamp to cool
before switching back on).
The energy efficient warehouse light solutions - T5
fluorescent tubes, induction lamps and LED are fully compatible with
switching/dimming control systems and so can offer further energy saving
opportunities - see these below:
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Other advantages of new lighting systems
A new warehouse lighting system can provide many operational
benefits for the users of the building space as well as financial benefits for
the operators. This is covered in the next
part. |
Part 5 - Other advantages of new lighting
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There are many other areas where new lighting technologies
can make operational improvements on a existing warehouse lighting system. These
provide further benefits for the warehouse users, the building manager, accounts
etc. |
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A list of the further benefits of new warehouse
lighting is shown below:
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Lower maintenance costs - In warehouses, a
scissor lift or cherry picker may be required to change expired lamps - which
can be costly (as well as the disruption caused when an area remains unlit).
Also, new environmental regulations mean that expired bulbs have to be carefully
disposed of. New light fixtures use bulbs that last up to 50000-100000 hours; or
6-9 years continual operation. This means lighting
maintenance and disposal costs can be almost eliminated
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Government financial
assistance - Due to the level of energy & carbon saved, new
warehouse lighting will usually qualify for Carbon Trust financial assistance -
either through an interest-free loan or write off of investemtent against tax.
This means a new lighting system could cost nothing
to install as the savings are larger than payment installments (a positive cash
flow )could be generated!
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Improved light quality
- The quality of light from older high-bay fixtures can be poor
(especially from HPS lamps) - new lighting technogies can emit light that is
close to daylight. This means beter colour
recognition for product identification & picking and a safer working
environment.
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Improved light
distribution - A poorly designed warehouse lighting system can can
cause problems for workers - e.g. large shadows between high shelving making
label reading/product picking difficult or forklift truck drivers experiencing
high levels of glare. A new system can address these problems by fully
considering the building users. This means better
health & safety standards & productivity will be
achieved
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Respond to the sustainability
demands of your supply chain & customers - increasing awareness of
environmental issues has put green issues high on business agendas. Energy
saving warehouse lighting provides one of the most effective ways to
significantly lower the carbon footprint of a business. This means a business gets a very visual display of their
to sustainability commitment |
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A summary...
Installing new warehouse lighting is a business investment
with a quick payback that provides many operational benefits and can qualify for
Carbon Trust assistance which elminates any cost
barriers |
Part 6 - Important warehouse lighting points
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The wide range of warehouses and commercial storage buildings
mean that if you are seeking a new energy efficient lighting system you need to
carefully consider your specific requirements to find the most appropriate
solution. Some key points are:
If you already know this information the Green Business Light can give you
a head start on getting your warehouse project started - go here
to get started. |
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The key features of warehouse lighting systems include:
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Lifetime cost – including energy usage and maintenance
(bulb replacement, disposal etc.) costs
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Lamp efficacy – measured in lumens per watt, the amount of
light produced for the power input
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Light distribution – the spread of light from the
fixture
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Colour Rendering Index (CRI) – the appearance or "quality"
of the light measured as a figure from 1-100 - a figure of 100 represents
daylight , a sodium street light is around
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Lamp lifetime - time until end of useful life due to
excessive depreciation of the light output or failure
An overview of older warehouse lamps is given below:
- T8 and T12 fluorescent tube lamps - Good quality
light but difficult to use at high mounting heights
- High pressure sodium (HPS) lamps - these produce the
highest efficacy of HID light sources but give a poorer light quality (low
colour perception) - HPS lamps have 12000-15000 hour lifetime
- Metal halide (MH) lamps – these provide a crisp
white light (the best colour rendition of all HPS light sources) with a lamp
lifetime of 8000-12000 hours. New metal halide fixtures are available with
electronic ballasts, providing longer lifetimes and higher efficacy .
The details of new warehouse lighting is detailed below:
- Fluorescent T5-tube lights – New high-output T5 tube
light fittings give a lifetime of 10000-18000 hours and high CRI
- Induction lighting – An ”electrode-less” version of
fluorescent lighting that is becoming increasingly affordable and offers very
long lamp lifetimes - up to 100000 hours and therefore very suitable for “fit
and forget” application. Also provide an excellent light quality
- LED lighting - A new solid-state lighting technology
that will have a very large role in the future of business lighting. These also
have the potential of 50000 hour lifetimes and high lighting efficiency but
presently entail a high capital cost
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