Three ways to light a swimming pool

At the risk of stating the obvious, pools are constantly damp and wet. Even in the best air-conditioned pool, the luminaires must resist high humidity and temperatures. Unless the luminaires are very high up, they will be splashed. You’ll need products rated IP54 or more.

Some pools have a false ceiling, and the void is used to extract the warm, damp air. If you are using a recessed luminaire, remember that the temperature in the void can be well over 40°C. Also, the upper sections of some recessed luminaires are not IP rated.

Although pools nowadays don’t use as much chlorine as they used to, the chemical can still attack some popular grades of stainless steel, turning it black and pitted. Powder-coated finishes normally solve the problem as long as they are good quality and not damaged during installation.

The other major design consideration is safety for swimmers. Reflections from the lighting should not prevent pool attendants from seeing a swimmer in trouble. The SLL’s sports lighting guide, LG04, gives suitable geometries for the luminaires in relation to the pool surface to minimise distracting reflections.

Lastly, don’t forget maintenance. Luminaires positioned over the water will be hard to access – and cause glare to swimmers doing backstroke.

Our pool measures 15 x 30m and is 8m to the eaves. We have included a seating area mounted high up on one side.





This may be an old-fashioned solution, but it’s well worth considering. I have used an IP54, twin 58W T8 fluorescent unit with a wrap-around diffuser. The body is GRP so there should be no corrosion problems.
The luminaires have been positioned above the pool edge, over the tiles. This gives maximum illumination where you need it most. They can also be maintained easily. There is good vertical illumination thanks to the wrap-around PMMA diffuser.
The recommended horizontal illuminance for pools is 
300 lx and this scheme achieves 335 lx with excellent uniformity. Even the centre of the pool receives over 250 lx. Most pools have white – or pale – tiles so plenty of light is reflected upwards.
The big disadvantage of this solution is the maintenance. Although the T8 has a 15,000-hour life, there are 46 fittings – and so 92 lamps to change.


Luminaires 46 Trilux model 7132 with 2 x 58W T8 tubes
Optical control Opal, acrylic wrap-around diffuser
Arrangement Around perimeter of pool
Average illuminance Eh on pool 335 lx
Electrical load 11W/m2
Typical cost £6k
Pros A simple solution
Cons Maintenance and electrical load

This solution using Trilux’s Mirona LED high bay uses less than half the number of fittings of the T8 scheme, and is the most economical in W/ m2. This is mainly because of the more efficient LEDs and the fact that more of the light is directed downwards. For a given illumination on the water, there is less light on the walls than in a fluorescent scheme.
The narrower light distribution means we have had to mount the Mirona higher up to give a wider spread of light. We have also had to position some over the pool. However, we have managed to limit the number over the water to just six. They are fitted with a low glare diffuser, but they would still be more intense to look at than the fluorescent.
Maintenance will be minimal because after 50,000 hours the sources are still achieving L80.
Cool LEDs emit more light than warmer ones, so it is tempting to maximise the scheme efficiency in this way. But a colour temperature that’s too cool emphasises blue veins and makes people look pale and cadaverous. I’ve gone for 4000K.


Luminaires 20 Trilux Mirona with 4000K LEDs IP65
Optical control High spec reflector with acrylic cover
Arrangement As shown
Average illuminance Eh on pool 345 lx
Electrical load 5.7W/m2
Typical cost £14k
Pros Efficient and low maintenance
Cons Possible glare to swimmers

One of the best ways to light a pool is to use wide angle floodlights that reflect light off the roof. This totally avoids any chance of glare to the swimmers. It also provides good illumination on the walls and people’s faces.
This option has by far the lowest capital cost, albeit the running costs are higher than the LED solution.
We have mounted 400W metal halide floods high up on the walls. Using warm 3000K lamps is more sympathetic to people’s complexions. The viewing platform is high, so we have fitted visors on the underside of the floodlight to prevent direct viewing of the lamp/reflector. Obviously you must position equipment so no one can touch the hot luminaire.
It is relatively easy to access fittings for maintenance. Apart from excellent colour rendering, metal halide lamps have much better life and lumen depreciation than they used to. This scheme won’t work if the pool has a glazed roof.
The best aspects of this scheme are that the space looks light and airy and the initial cost is low.


Luminaires Combial 400W HST floodlight IP65
Optical control Asymmetric wide angle reflector, toughened glass cover
Arrangement Mounted on wall, as shown
Average illuminance Eh on pool 335 lx
Electrical load 8W/m2
Typical cost <£1k
Pros Light and airy
Cons You must choose the right metal halide lamp