Update your lighting#
If you still have any fluorescent lighting, you’ll want to replace it urgently as you won’t be able to get fluorescent lamps or tubes after September 2023. Some venues still have high pressure sodium (HPS) lighting. LEDs use 40-75% of the energy of HPS. The higher the wattage, the bigger the energy savings of switching. LEDs also provide a better light quality than either fluorescents or HPS.
Ordinarily we’d say it that if you already have all-LED lighting, then changing to newer LEDs wouldn’t pay back - but that depends on the price of electricity. New generation LEDs use about half the power of first generation ones for the same number of lumens. You can check whether a change is a good idea by estimating the number of hours a day the LED is on and calculating how many kWh/day the old and new lamps would take. Keep in mind that there is a carbon cost to making the lamp as well. We think a more likely reason to change first generation LEDs is simply that the light quality has degraded.
Before spending money, think about whether the lighting is right - the right level of light in the right areas. For high ceilings, sometimes it’s better to have luminaires (fittings) that suspend the lights lower down than ones that mount directly on the ceililng itself. Also think about how robust the luminaires need to be, particularly if people play sports in the space.
You also don’t want to put a lot of money into new lighting for walls or ceilings without considering whether the wall or ceiling they are mounted on needs a big change first. For instance, if you need major works to put in internal wall insulation or to drop a ceiling so that it’s easier to heat and insulate a space, it’s better to do that first if you can.
Retaining your existing fittings#
With either fluorescents or HPS, the cheapest option is usually to put retrofit LEDs into the same luminaires (“fittings”) as the old lamps (“light bulbs”). Sometimes you won’t be able to find a suitable retrofit LED and will need to change the luminaires instead or switch to LED floodlights. You’ll also want to consider whether the luminaires are near end-of-life and should be changed.
If you are considering retrofit LED lamps, you’ll need to think about:
whether the LED replacement will fit in the luminaires. LED lamps tend to be larger than other kinds.
whether you need the replacements to be dimmable. Not all LEDs are.
the number of lumens the LED supplies. This tells you how much light they give and is more informative than the number of watts.
the light colour - whether it is warm white, cool white, or whatever. The safest way to compare is using the number (like “2700K”).
the energy efficiency rating of the lamp - higher energy efficiency lamps are cheaper to run and tend to be better in other ways as well.
the beam angle - whether the lamp focused the light for a specific area or spreads it for general illumination. Getting the wrong one can leave you with light and dark patches.
whether you’re putting a high power LED in a small enclosed fitting. This won’t work if it causes the LED to overheat.
For low voltage lamps, you may need to replace the transformer or dimmer as well as the lamps. Transformers designed for older kinds of lamps don’t deliver stable enough voltage and often can’t supply low enough power for LEDs, especially if there aren’t many of them on the same circuit. You need to check this ahead, as the wrong transformer can blow the LED lamps when they are first turned on.
For fluorescent tubes, sometimes as well as changing to an LED tube the luminaire needs rewired. There are retrofit tubes that are compatible with fluorescent ballasts without rewiring, but ideally you’ll want to bypass the ballast. This is because the ballast takes unnecessary power and will probably break before the tube does, increasing your running costs and forcing you to buy a new tube early.