Ben, an earnest young project manager brings his new idea to the board meeting – replace our ridiculously outdated metal halides for new, singing-and-dancing LED’s.  ‘Everyone is doing it, the whole world is changing to digital LED – it must be the right thing to do!’ Thoroughly researched, he is confident of 100% buy-in from all.  The features are great, the benefits are blatantly obvious. Then, the boss asks the dreaded question ‘That’s all very well but what’s the return on investment (ROI)?’  Ben fumbles around restating the features and benefits for the fourth time.  Opinions are divided and another amazing project get scuttled before leaving the harbour.

The “ROI” question is perfectly fair to ask and not always easy to answer.  So what we’ve attempted to do is give a clear matrix of influencing factors in relation to replacing metal halides with LED lamps.  We have focused on replacing metal halide fittings on a one-for-one basis, although the calculation is still valid for new build, assuming you select an LED fitting that will allow you to use the same pole construction as you would with a metal halide fitting i.e. luminaires are the same size and weight.

The main and obvious influences on ROI are power consumption and maintenance costs.  However, a number of external factors also will impact a decision like this which are more emotional things which everyone will put a different value on.  These are all benefits we take for granted in our homes and businesses but at this early-ish stage of LED development can be easy to overlook in a sporting application when club funds are stretched.  These include carbon footprint responsibility, spill light control to have happier neighbours, the convenience of digital app based control and ‘instant on’.  Basically the convenience and usability we expect in the 21st century which is often hard to put a price on directly.

Carbon footprint responsibility

There may well be differing views on global warming and how this is impacting our planet and what sort of crises we are generating for future generations.  Whichever end of the scale we are at in this argument, saving electricity has to be a good thing.  In most countries electricity production is stretched and costs are only going to go one way.  Additionally many municipalities offer incentives to use more efficient devices, further enhancing the benefits.

Happier Neighbours

Spill light not only costs money in wasted energy but also makes for aggravated neighbours.  Having a pay-to-play system is good news for the club who can maximise their investment, but perhaps not such good news for those nearby who don’t like sleeping in simulated daylight.  Many LED systems offer excellent light control due to each LED having an optic.  This allows for very specific focus of the light to go just where it should, dramatically reducing the stray light.

App based control

Imagine your facilities manager being able to turn the lights off from his bed at 2am when the last rowdy players have forgotten to do so. Better still, set the app so that the lights turn off after a specified time, or when the key-holder leaves, or when the players’ credit has run out etc. etc.  In other words, digital lighting gives us exceptional control of how we manage our lighting to minimise running costs and maximise the clubs ROI.  By making pay-to-play so simple and controllable, clubs can rethink how they make the facility available 24/7, boosting attendances and fees without impacting on their pay-roll.  Additionally, being able to control the intensity of the lights allows you to have different levels of lighting for different sports or levels of play.  This again gives more control of your costs as you can dim the lights to pre-set levels if full power is not required.

Instant On

Have you ever been frustrated with how long your lights take to warm up?  Or worse still had a match in progress and the electricity has tripped, causing a 20 minute delay while the lights warm up to full power again?  A benefit of LED that is hard to put a value on is the way they power up in seconds.  Even with a soft start they are operating at full power in under 5 seconds.

Digital Convenience

Like with many things in our modern world there is a convenience about digital which is hard to put a price on.  Ever considered what life would be like without a smartphone? We now can’t even imagine how terrible this would be but smartphones have only been in existence since 2007. Once we have made the commitment to going digital the benefits compound and it becomes very difficult to image how we managed ‘in the old days’.

Conclusion

So, bearing in mind the somewhat ‘intangible’ benefits mentioned above, put your numbers into the ROI Calculator below and you’ll quickly be able to see how long the investment will take to pay off.

Tennis court lighting, like most things in life, vary dramatically depending on the type of usage and personal preferences.  In principle, the ball is small and moves fast.  This usually requires a higher level of lighting than, say, a football.  The important thing to bear in mind is that it is always cheaper to do the job right the first time than to have to redo it in 2 years’ time.  Other factors will include how close are your neighbours and how much do you want to spend.

Lighting levels

This would be the first consideration as everything else will be based on the lux levels required.  For basic play and just to have enough light to see the ball a minimum of 100 lux is required.  This would be suitable for a late night fun game, however, if you are more serious and using the court for training you should really be working to 250 lux.  This will give you sufficient light for higher speeds of play and would be where many good clubs operate their lighting levels.  At the next tier up, competition courts operate at 500 lux.  These lux levels allow for high speed play and would be suitable for any class of player.  Any light levels are achievable, it just depends on where you see your style of play in relation to the budget you set.  To go from 100 lux to 500 lux would require approximately 2.5 times the poles and light modules.

Along with the overall lighting level, uniformity, or evenness of the spread of light is equally important.  It is not sufficient for a designer to quote an average lux level as this could vary from 500 lux directly under the fittings, to 100 lux in centre court.  The average may be 250 but the useableness of the light will be hampered by being patchy and uneven.  You therefore need to ensure that the uniformity factor is round 0.4.

Light Control

In order to make sure your friendly neighbours stay friendly, check the lighting plan provided by the supplier to ensure there is no spill light at ground level.  Also ensure the lights mount horizontally.  This will tend to be the more specialised lights as many of the cheaper modules will mount at an angle.  Whilst these angled units are less expensive, they can cost a lot in relationships as the glare from these lights can be literally seen for miles.

Pole Height

For domestic courts this is usually best to be kept as low as possible to minimise glare and over-spill light.  Depending on the light fitting used and the lighting levels required a height of 6m to 8m is usually feasible.  For public areas poles up to 20m are used, particularly when lighting a number of courts from a restricted number of poles.  This height make uniformity easier as the light spreads naturally when given more distance.

To compensate for the lower poles it is often necessary to use more poles.  For instance if using 10-15m poles, 4 would be sufficient to get 250 lux and good coverage.  If 6-8m is ideal then 6 poles may be required to get the same results or 8-10 poles to achieve competition lux levels.

The main problem with metal halides was that when bulbs needed to be changed, the higher the poles the bigger the hassle. With LED’s having now come into their own in terms of reliability and longevity, keeping pole height down to make servicing easier is no longer an issue.

Remember that often these poles, although galvanised to resist rusting, can be powder coated or painted to suit your environment.  Black or white are common but other options are often available on request.

Pole installation

Lighting poles are now available virtually off-the-shelf from a number of reputable suppliers.  They conform to relevant regulations and the manufacturers can provide drawings and specifications to help aid a council planning submission.  The poles are mostly supplied with a complete installation kit including a frame structure which gets concreted into the ground.  This, along with the installation instructions, makes it simple and safe for any good contractor to install the poles.

Electrical requirements

The typical current draw for a tennis court will be from 2.4kW (less than a kettle to boil water) for achieving 100+ lux up to 6kW which would provide competition level lighting with 10 poles.  The modules typically are supplied with an LED driver which can be mounted at the base of the pole or may be integrated into the design of the lamp.  Whilst the wiring up and installation is simple, ensure that a qualified electrician does the installation and that the modules are compliant with local regulations.

Conclusion

This planning work will put you in good stead to have a lot of fun for many years to come.  A cautionary note would be to use this guide to cross check what you are told by contractors.  Sometimes things that are simpler, easier and cheaper for them may not be best for you in the long term.

Good luck and enjoy the game!

We often get asked the question ‘Can I replace metal halide bulbs with LED bulbs in the same fitting?’ Whilst this would be nice and convenient it is unfortunately not possible at present.  That is not to say it will never be possible.  As most of us over-30-year-olds can testify, things that were totally impossible are suddenly and surprisingly ubiquitous the next minute.  For those under 30 nothing is any longer regarded as impossible, so watch this space!

Although all lamps generate heat in some form or another, the way metal halide and other traditional forms of lighting work is very different to LED.  Metal halide lamps push their heat forward.  This means that they need a glass or high-temperature plastic cover to cope with the heat.  However, the body or frame holding the bulb itself can be light and thin, often mild steel or plastic as there is no heat coming out the back of the lamp.  By contrast LED’s generate a lot of heat but it flows out the back, with very little coming forward.  In this way a plastic lens can be used for the front, but requires an aluminium heatsink as the back part of the housing to help remove the heat build-up.  This simple contrast means that (for the moment) the way the 2 types of lamps operate is fundamentally too different to be able to make the change simply by replacing bulbs.

Whilst we are aware there are products on the market which claim to do this swap out, be very careful.  At this point a realistic wattage replacement is 1.2kW of LED for a 2kW of metal halide power.  As of mid-2018 this would be regarded as a highly efficient sports light.  This means that the heat generated is equivalent to 240 x 5W domestic lamps, but crammed into a light that is about 600 x 600mm.  If you were to further reduce this size to that of a 2kW bulb, it is technically, and practically, impossible to remove the heat.  As a build-up of heat would destroy the LED’s, this leaves the only other conclusion that it cannot therefore produce the right amount of energy. This is of course simple to prove.  Get lux readings of your existing lighting layout and then ask the supplier of the alternative bulbs to do the same.  If they don’t have the facility to produce lighting layouts it is very unlikely that the product will work.  If they can prove that it works then you know that science has again progressed and we need to do some catching up.

The response is often ‘Well it works at home!’  This is perfectly true and is only possible due to the low current draw of these lamps and, consequently, the low amounts of heat that will be generated.  The more that is expected out of a lamp in terms of light output, the more heat will be generated.  Domestic lamps are often only 3 or 5W but produce a good glow in their setting.  Compared to a high intensity lamp like a sports fitting, these domestic units are very large by comparison, giving a lot of surface area which also helps dissipate heat.  If a sports light was created that used domestic 5W bulbs it would likely measure more than about 2sqm.  Space in the ceiling of house is not really at a premium, hence light fittings don’t have to be very streamlined.  However, having a large and heavy light 25m in the air increases the cost and engineering challenges for the pole manufacturers.  Additionally, if clubs are wanting to replace metal halide fittings with LED, the modules have to be similar to the metal halides in dimensions and weight for the same reason.

The only viable solution currently is to have a module that is matched in size and weight as mentioned, but then also has optimised light output to compare with the metal halide.

So, proceed with caution if the option looks too simple and cheap.  As with most things in life, if it looks too good to be true, it may be just that!

If you have looked into LED lighting at all you will have noticed there is dozens, if not hundreds, of options.  So, as you can imagine, there a dozens, if not hundreds, of variations to the answer of this question. They range from 100W to 1500W, big fins, small fins, fan assisted, metal pressed, die cast, white powder coat, black powder coat, COB’s, small chip LED’s, high efficiency LED’s and so on and so on.  Your head begins to spin at the options, but one thing you can be sure of is that LED is the most efficient – right?  Wrong.  Or more correctly – potentially wrong.

Let’s just confirm that point quickly as it is really important – just because it is LED does not mean that it is energy efficient.  Or, conversely, just because it is old technology metal halide does not make it inefficient.  A number of factors need to be assessed to decide if LED is going to work for you.  How often are the lights used, and for how long etc. etc.

So let’s look at some of these factors in a bit more detail…

How often are the lights used and for how long?

A while back we had a client insisting on looking at LED.  They ran a rodeo once a year for one night and he felt LED was going to give him the best return on investment because if ‘was the best’ and ‘the latest technology’.  Needless to say we were dubious.  The LED fittings he wanted cost 4 times that of metal halide and the amount of electricity used in the year would have only been 10’s of dollars because of only being used once a year.  In this case there was no way of justifying the purchase.  On the other hand, making a 40% energy saving on 100’s of hours of use per year can make it very viable.

How many lights will I need to use?

The only way to conclusively check if there is a gross energy saving is to get a lighting plan done.  If you are using the existing poles then you can figure out what lighting levels you already have and get a comparative study done using LED.  You can immediately see if you will require more or less fittings and energy by the layout results.  Don’t take this as a given that LED will reduce your energy consumption.  Most systems are less efficient than their traditional alternatives.

Optics and field size

The larger the field, the more difficult it is for LED to improve on power consumption.  This is because many of the LED optics are not optimised for big field sports and are therefore very inefficient at distributing the light, particularly at a distance.  The critical factor is the control of the light with optics or reflectors as this determines ultimately how many LED watts will be required.  Again, a lighting plan using the IES file for the specified light is the only way to know if it will work or not.  Don’t baulk at this step.  It may cost a few hundred dollars at worst, and at best could save you hundreds of thousands in wasted investment.

To conclude then, efficiency is relative to the size of the investment vs the usage of the lights.  Assuming you get a really good optic and can replace your metal halide fittings and get a 40% saving in electricity, make sure you get a sensible return on investment by looking at the whole lifetime cost, rather than just focusing on the isolated factor of energy consumption.