- Switch in parallel
Consider wiring light switches to control lights in zones parallel to windows. Then lights above windows can be switched off, while those in the centre of a room are switched on, allowing occupants to make the most of natural daylight.
- Time control
Timers can be particularly useful in the control of slow response lighting usually found mounted at heights above 5m. This type of lighting takes time to warm up (and cool down) so should not be switched on and off too often while the building is occupied. Time controls can ensure it is not left on when the building is empty.
- Occupancy control
These controls are often used in external security lighting. They turn off lights after a set time where no movement is detected and can be particularly useful in conjunction with a manual switch or time control. Also useful in toilet, cloakroom and storage areas, where they can be linked to ventilation fans to ensure lights and fans are switched together.
- Photoelectric switching and dimming
Responding to light levels, they can switch lights on when it is sufficiently dark. A relatively new use is to control the dimming of fast response lighting (eg tungsten or high frequency fluorescent lighting) to ensure a specified level of illumination. This is most often used to control lights next to windows.
Replacement opportunitiesMake sure that you have the most efficient type of lighting installed. The following table will help you identify different types of bulbs and whether there might be a more efficient alternative.
| Existing lamp type |
Energy-efficient option |
Energy saving/benefit |
| Tungsten light |
Replace with compact fluorescent lamps (CFLs) in the same fitting* |
75% plus longer lamp life |
38mm (T12)
fluorescent tubes
in switch-start
fittings |
Replace with equivalent 26mm (T8) triphosphor fluorescent tubes of lower wattage |
8% plus
longer lamp life |
High-wattage
filament lamps or tungsten halogen lamps as used in floodlights |
Replace with
metal halide or high wattage compact fluorescent lighting |
65-75% plus
longer lamp life |
Mains voltage reflector lamps, filament spot
and flood types |
Replace with
low-voltage tungsten halogen lighting or metal halide discharge lighting |
30-80% for equivalent
lighting performance |
Fluorescent fittings with the old 2ft 40W,
and 8ft 125W fluorescent lamps |
Replace with
modern efficient fittings using reflectors/louvres or efficient prismatic controllers with high- frequency electronic or low loss control gear and triphosphor lamps |
30-45% with much improved lighting quality. The use of high frequency electronic control gear eliminates flicker, hum and stroboscopic effect |
| Fluorescent fittings with opal diffusers or prismatic controllers which are permanently discoloured |
Replace with new prismatic controllers or replace complete fittings as above |
No reduction in energy consumption but increases the amount of light by between 30% and 60% | *Take care where tungsten lighting is used as task lighting for machinery in workshops. Replacing them with CFLs can cause a stroboscopic effect, so tungsten can sometimes be the safest option. An alternative is to use a CFL fitting with high-frequency electronic control gear, which eliminates the stroboscopic effect.
Fluorescent lightingFluorescent lighting is the most popular kind of lighting in commerce and industry in the UK.
- Tubular fluorescent lamps
Up to 10 times more efficient than incandescent lamps and can last up to 18 times longer, depending on the type of lamp.
- Main uses
Offices and all commercial buildings, homes (eg in kitchens and garages), most low level (under 5m) industrial applications. Compact types are suitable as replacements for tungsten lamps.
- Tri-phosphor coated fluorescent tubes
These do not dim as much with age. They provide a natural, brighter light for the whole life of the tube.
Fluorescent lights with tri-phosphor coatings last longer and don't dim as much with age:
Replace blackened, flickering, dim or failed tubes with tri-phosphor coated ones.
- Specify modern high-frequency fittings during refurbishment
With less heat, no flicker or hum, extended lamp life and the possibility of dimming, these fittings have a lot to offer businesses. Always specify tubes with a tri-phosphor coating to ensure lighting levels do not dim as the installation ages.
- Replace or remove failed fluorescent tubes
The light fitting will continue to use power whether the lamp is working or not. For a mains frequency tube this would be around 25% of rated tube power. High frequency fittings will use around 10% of the tube rating.
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