We Supply & Install Energy Efficient Warehouse Lighting Across England & Wales

Our Warehouse Lighting Energy Guide

Lighting can account for up to 80% of the electricity costs in all types of warehouse, storage and logistics buildings.

Businesses who choose to invest in an energy saving warehouse lighting system can cut this energy usage by around 50 to 90%+ - making significant financial savings year on year and getting a fast return on investment.

The below guide to warehouse lighting provides you with essential information on:

1. How a well planned efficient warehouse lighting system can save energy
2. How new warehouse lighting can improve productivity and safety
3. The inefficiencies & power losses of outdated lighting systems
4. The advantages of new efficient lighting technologies (including LED)
5. How to carry out a calculation on warehouse lighting energy savings

How can new lighting save energy?

A newly installed energy efficient lighting systems will reduce a warehouse building energy requirements by:

1. Changing inefficient light fittings - older low and high bay fittings (sodium, metal halide, T12 fluorescent tubes) are switched for new energy efficient fittings (such as LED & T5 fluorescent tube) so that the same amount of light is produced but with a much lower energy consumption
2. Optimising the positioning/spacing/directioning of light fixtures - to correctly match the lighting fixtures to the layout of warehouse aisles and other key areas
3. Using intelligent light control systems - to automatically adjust lighting levels in pre-defined zones (individual or groups of racking aisles etc.) in response to presence detection and/or existing daylight levels

Required quality in warehouses

The aisles and open spaces of warehouses, storage facilities, logistics/distribution centres etc. require adequate illumination from lighting systems so that:

• Stored items can be easily identified and retrieved
• Workers & vehicles (e.g. - forklift trucks) can navigate through aisles safely
• The risk of accidents and damage is minimised

What are warehouse lux level requirements?

The recommended internal lux levels (lux being a defined measurement of light intensity) that needs to be produced by the warehouse lighting system will vary depending on the exactly the type of building and the work carried out inside.

Some relevant lux level examples as defined by CIBSE are reproduced below:

Deterioration of warehouse light levels

Over time the lighting in a warehouse will become unfit for purpose due to the age of the light fittings (these are referred to as "luminaires" in technical literature) - that is to say - the fittings do not emit the same light output levels as when originally installed.

It is also not uncommon for warehouse light fixtures to be badly aligned with aisles - especially if the racking layout has been altered in the past or the building has been converted to a warehouse from a different use - and the light fixture spacing has not been subsequently re-positioned.

Risks of poor warehouse lighting quality

Poorly performing or badly designed warehouse lighting systems can create significant expense via the following types of losses:

• Accidents - possibly involving fork lift trucks, reach trucks or side loads with personal injury or damage to valuable stock a likely possibility
• Increased staff absenteeism - through reported symptoms like stress, eyestrain, migraine and headaches;
• Reduced working efficiency/productivity - difficulty with product identification & picking etc.

Good warehouse lighting design

As well as producing necessary light levels for the onsite work, any warehouse lighting installation must adhere to the general principles of good warehouse lighting design.

There are a number of general rules which take into account building users in order to achieve better health & safety standards (and maintain/achieve business certification standards -such as ISO 14001).

Examples of good warehouse lighting practices

Some good examples of best practive to maintain a warehouse lighting system include:

High fixture positioning

The light fixtures should be positioned as high as possible to prevent likely damage from regular stacking/removal of goods and fork lift/cage vehicles

Even light distribution

A good warehouse lighting system will produce reasonable uniformity across the warehouse floor and eliminate problems such as:

• Large shadows or dark spots
• Forklift truck drivers experiencing high levels of glare/dazzle
• Light being "wasted" on top of racking etc.

Specifying a good light quality

The quality of light from outdated warehouse low/high-bay fixtures can be poor - especially the yellow tinted light from sodium (referred to as SoN or HPS) lamps or the skewed green tinted light from failing metal halide luminaires.

New low energy lighting technologies (e.g. - LED & T5 fluorescent) can emit light close to daylight colour and an almost full light spectrum output.

Undertaking regular maintenance

By maintaining light fittings an lamps this an ensure the light quality in the warehouse will always be to a basic minimum standard. Such steps can include:

• Regular cleaning of warehouse light fittings (to remove dust & debris etc.)
• Regular relamping of lights which may otherwise deteriorate in lumen output

Outdated warehouse lighting types

Typically, an older warehouse lighting system consists of several "high bay" or "low bay" lighting fixtures, ideally positioned above the centre of aisles (mounted 5 metres or higher from ground level).

Older warehouse lighting systems can run at a very low efficiency by:

• Employing outdated, inefficient lamps & fittings
• Operating the lights at times when not actually required

The light fittings that are employed in older warehouse lighting systems are usually one of the following technology types:

HID (high intensity discharge) lamp fittings

HID lamps are rated 250 or 400 Watts which are either high-pressure sodium (yellow tinged light) or metal halide (a white-blue tinted light). Low pressure sodium and mercury vapour lamps are much less commonly found versions of these types of HID lamps

Outdated T8 & T12 fluorescent tube fixtures

These includes batten fixtures using 8 foot long T12 and older T8 tubes) these are more common at lower mounting levels (e.g. under warehouse mezzanine floors) but they can be used on suspended chains to provide the main lighting source for warehouse aisles as well (although this is less common)

Inefficiencies of older warehouse lighting

An outdated warehouse lighting system will be inefficient (e.g. wasting energy) due to a combination of factors:

Loss 1 - Output of high proportions of heat

As well as light, heat is emitted from lamps- the temperature of an HID bulb can reach 200-300 degrees Centigrade (in certain types of warehouses this strain the cooling load of the environmental system - an additional needless expense)

Loss 2 - "Additional" energy consumption of the light fitting

Older HID and fluorescent light fixtures use inefficient magnetic control ballasts which necessitate a significant extra energy requirement. Typically this is accounts for an extra 10-25% of power consumption over and above the displayed lamp rating!

Loss 3 - Lower efficiency with age of light fitting

Over time warehouse lighting fixtures become less effective at generating & directing light where required. Examples of this include:

• Dust & debris build-up on the fitting casing & reflector
• Ageing of the electronics contained within the control ballasts of light fittings - e.g. capacitors - this results in lamps being overheated and a blackening of their glass surface

Loss 4 - Non-adjustable lighting levels

Older HID and fluorescent light fixtures cannot be instantly dimmed or switched on & off. For example: sodium & metal halide lamps require a ‘warm-up’ time of at least 5 minutes (to reach 90% of full output) and an 're-strike' time (for a lamp to cool before being switched on again).

The newest energy efficient warehouse lighting systems combine high efficiency light sources, well designed-fittings and sophisticated "instant-response" control systems...

New Energy Saving Light Fittings

New energy efficient warehouse lighting systems can cut the power requirements of older lights by up to 80% without compromising on the level or quality of light - this is achieved by:

1. Installing the latest energy saving light fixtures (or luminaires) with high efficiency light sources(including T5 fluorescent tube, induction lamp & LEDs)
2. Installing intelligent control systems which are compatible with the instant switching/dimming capability of new light fittings - NOTE: control systems are addressed separately in the next section

An overview of T5, induction lamp & LED light technologies is below:

T5 fluorescent tube lighting

These fixtures typically use 2, 4 or 6 T5 fluorescent tube lamps in a fixture (with a highly polished reflector) to ensure all light is directed towards the warehouse aisles and floor.

The T5 fluorescent tubes work on the same basic principle as older T8 & T12 tubes (NOTE: The number after 'T' refers to the diameter of the tube as measured in eighths of an inch).

The advantages of T5 fluorescent tube lighting

Some advantages of T5 lighting in warehouses include:

• A well established energy efficient lighting technology
• A modest cost of installation
• High quality fluorescent tubes give a life of 12,000-18,000 hours
• Light fixture still produces light if a single T5 tube expires
• Electromagnetic ballasts can allow full dimming/switching of the lighting system

LED fixtures

These fixtures use a mounted cluster of high output LED (Light Emitting Diode) components that produce light when an electric current is passed through them. This solid state technology is continually being improved and cost is reduced.

Advantages of LED warehouse lighting

Some advantages of using LEDS in warehouses include:

• Long lifetime (50000-80000 hours)
• a uni-directional light source - so light is emitted as a "beam"
• The highest efficiency of any light sources
• Fully compatible with automated light level controls

Disadvantages of LED warehouse lighting

Some limitations include:

• LEDs may be limited in terms of light spread/distribution at very high mounting heights
• The correct reflector must be specified
• The heatsink of LED lights need to be kept clean
• The light can be regarded as 'cold'

However - caution must be exercised by any warehouse building manager when selecting LED high bay or low bay light fittings - like any electronic device you will get "what you pay for". Many cheap unregulated imported products are on the market and we are aware of warehouse building owners stripping out poor quality LED lights within 12 months of installation.

Please contact us if you are thinking of looking at LED lighting - there are a number of general rules you should follow to ensure you are buying the right product.

Induction lamp fixtures

Induction lamp fixtures are less common - however they use many of the same principles of light emission as fluorescent tubes. The key difference is rather than using electrodes to pass a current through a gas-filled glass tube to emit light, a generated electromagnetic field is used to 'excite' the gas in the tube.

Advantages of induction lamp warehouse lighting

The advantages of induction are:

• A very long operational lamp life (100,000 hours) - useful for "difficult" to access warehouse areas
• A high quality white light!

Retrofit lamp fixtures

There are energy saving lighting products for warehouses which attempt to "retrofit" a product into existing HID or tube lighting fittings. The main advertised benefit of these is reduced installed cost in comparison to all-new lighting system.

Our experience is that these products represent a stop-gap solution that do not maximise the potential savings and typically result in early failure.

Intelligent warehouse light controls

It is not uncommon for a warehouse lighting control system to be the 'bare minimum' e.g. - a default "ON" setting across all lights which is only turned off at the end of a working day.

The new energy efficient T5 fluorescent tube, induction lamp & LEDs fittings all have various abilities to be instantly dimmed and switched on/off when full light levels are not actually required. The job of the lighting control system is to provide signals to groups of lights in response to the conditions in the warehouse

The use of the energy efficient light fixtures and a well designed tailored energy saving control systems can be designed around individual warehouse working patterns.

New energy efficient warehouse lighting systems can cut the power requirements of older lights by up to 80% without compromising on the level or quality of light - this is achieved by:

Lighting Presence Detection Controls

Presence detection controls are used to detect the approaching people or fork lift trucks and send a signal to control the lighting accordingly. Inbuilt time delays prevent inappropriate 'off' switching if an occupant remains motionless.

Occupancy detectors can be acoustic, infra-red or microwave devices (and may or may not be built into each individual light fixture).

Daylight Level Controls

If the warehouse has an excess of 10% of roof area as skylight panels there may actually be no need for electric lighting at certain times of the day or year - photo-electric daylight linked controls can be used to gradually dim up/down warehouse lighting levels.

The controls are usually set so that the combination of daylight and electric lighting remains constant at the desired lighting (or lux) level. This means the energy consumption of lighting can be eliminated at certain times of the day.

Such intelligent control systems can ensure that the daily "average" power consumption of a light fitting can be much lower than it's rating and ensures maximum energy efficiency.

Other benefits of new warehouse lighting

So far in this guide we have looked at the DIRECT energy (& financial) savings that can be made from installing new warehouse lighting. However there are other key advantages to investing in a new warehouse lighting system based on LED, T5 or induction lamp technology. These are as follows:

• Lower indirect maintenance costs
• Lower business carbon footprint
• Beneficial financial schemes

Lower indirect maintenance costs

In warehouses, a scissor lift or cherry picker can be required to change expired lamps - this can be costly (as well as the disruption caused when an area remains unlit). Environmental regulations mean that expired bulbs have to be carefully disposed of (especially lamps containing the chemical element mercury - Hg).

Newer light fixtures which can last several years means that lighting maintenance and disposal costs can be virtually eliminated.

Lower business carbon footprint

The ever-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 a business carbon footprint (as well as being a very effective "visual" display of commitment to corporate social responsibility).

There are also many certification standards (e.g. - ISO 14001) that require continual improvements to be made.

Beneficial financial schemes

Due to the extent of energy & carbon saved, low energy warehouse lighting system installations will typically qualify for various financial assistance options - two of these are below:

Enhanced Capital Allowance

This represents a write off of investment against tax in the first year - some additional information on ECA allowances is here

"Pay As You Save" loan schemes

This is a financial arrangement set up between end customers & lighting installer/supplier. A loan is set-up such that the energy savings which are made are less than the monthly repayment instalments (a positive cash flow).

The advantages of this is that a new warehouse lighting system could involve no up-front capital to commit to.

Worked Example - Lighting Energy Savings Calculation

A worked example of the savings made by an energy efficient warehouse lighting installation is illustrated below:

Part 1 - Calculate the cost of existing lighting

1a - Gather information on the existing warehouse lighting

• There are 120 x 400W metal halide low-bay light fittings in the warehouse
• The lights are switched on continually for 16 hours a day, 6 days a week (all year)
• The customer is paying an average electricity tariff of 11p per kWh

1b - Calculate the existing lighting circuit load

Multiply the 120 low bay fittings x the 475W load per light (400W lamp + 75W ballast power)

= 57,000W = 57 kW total load

1c - Calculate annual warehouse lighting energy consumption per year

Take the warehouse lighting circuit load and multiply by the number of hours on per year

= 57 kw x 4,992 h (16 hours/day x 6 days/week x 52 weeks) = 284,544 kWh

1d - Calculate the annual warehouse lighting energy spend per year

Multiply the annual energy consumption by the electricity tariff to get the annual cost of operating the warehouse lighting

= 284,544 kWh x 11p/ kWh = £31,300

Part 2 - Calculate Cost Savings Of Upgraded Warehouse Lighting

A new high efficiency lighting system is proposed that can save 65% of the existing warehouse lighting energy consumption.

2a - Calculate the annual energy consumption of the new lighting system

= 284,544kWh x 0.35 (35% of original load - 65% power saved) = 99,590 kWh

2b - Calculate the new annual energy bill

Multiply the annual energy consumption by the electricity tariff

= 99,590 kWh x 0.11 p/kWh = £10,955

2c - Calculate the annual financial savings

Total Savings of £ 31,300 - £10,955 = £20,345 saved per year