Helpful Hints – Lighting confusion explained – Summer 2019 Articles

Whilst standing in a B&Q recently selecting some light bulbs, a 50plus staff member overheard a number of comments relating to how confusing people find lighting and bulbs in particular.  They are not alone, there has been much comment in the press as well. So here is a short guide.

1. Bulb types


  • The modern bulb
  • Typically use around 80% less energy than a traditional bulb and last much longer
  • Instant on, various degrees of white, colours as well
  • Available for most fittings and in an increasing range of colours
  • Dimmable versions available but see note on LED’s below

Fluorescent and compact fluorescent

  • The pre LED energy saving bulb
  • Typically use around 80% less energy than a traditional bulb but do not last anything like as long as LED
  • Warm up time noticeable and can get dimmer as bulb ages
  • Available for a range of fittings but being phased out
  • Generally not dimmable


  • The pre compact fluorescent bulb
  • Typically use around 10% less energy than a traditional bulb and doesn’t last much longer
  • Instant on
  • Usually warm white only
  • Being phased out
  • Nicely dimmable

Traditional incandescent

  • The pre-halogen bulb dating from the 1800’s
  • Relatively expensive to run and doesn’t last long at all in comparison to LED or fluorescent bulbs
  • Instant on
  • Usually warm white only
  • Generally phased out but ‘rough service’ models remain available (it’s a get around the ban)
  • Nicely dimmable

Note on LEDs:  If you want to dim an LED you must buy a dimmable version.  Note that dimming is subject to on-going development; LEDs do not dim like old fashioned incandescent or halogen bulbs to a really low level and require an LED dimmer.  Some LEDs can be purchased to work with voice control (Amazon, Google, BG, Philips etc.) or other control systems.

2. Wattage equivalence

Watts are a measure of power and in the case of light bulbs, power consumption. A modern LED bulb uses about one tenth of the power of a traditional bulb whilst providing the same light output.  So, welcome to lumens – a measure of light. As most of us still think in watts the table below provides a comparison of light output for differing bulb types.

3. The colour of light

Light ‘colour’ is measured in degrees Kelvin.  We are very used to two specific colours of light in terms of ‘white’; 2700 to 3000 degrees Kelvin from the traditional bulbs often called ‘warm white’ and 4200 degrees Kelvin from our office strip lights, often called cool white.

So this is what to look for when buying LED bulbs. One point of note: if you are elderly or struggling with your sight a little, then a ‘daylight’ colour of 5000 to 6500 degrees can help with close up work and reading.

Courtesy of 

4. Dimming

It used to be so simple, i.e. get a bulb, get a dimmer and the job was done. Sadly this is (currently) no longer the case. Firstly LEDs are not designed to dim so ‘work arounds’ are required to get them to do so or appear to dim to the human eye. Therefore, if you want LEDs that dim you have to buy ones where the electronics have been designed to do this. However, these won’t dim like traditional bulbs, they’ll only dim so far before they start to flicker. For this reason LED dimmers have a minimum setting, to stop the flicker. It does work to an extent, but it’s a retrograde step. You will notice I used the work ‘currently’. That’s because this is a developing technology and I’m pretty sure the problems will be overcome, in time.

5. Transformers – take them out

Many old halogen bulbs were ‘low voltage’. They used a transformer (for the techies amongst you, either a real transformer but in most cases a switch mode power supply), to reduce the 240 volt AC mains to 12 volts. There have been two issues with this: (i) the transformers, actually the power supplies, frequently fail and (ii) if you remember your school physics as the voltage goes down the current goes up if you want the same power (light) output. That coupled with the heat from these (mostly halogen) bulbs frequently results in arcing bulb to bulb-holder contacts and resulting failure.

In this case the switch to LEDs has simplified matters. It’s easy to remove the transformer, change the fitting using readily available and cheap adapters and fit 240V mains LED bulbs.

So yes you should switch to LEDs. If you are elderly and the bulbs are on for a long time you’ll save the costs within months through reduced electricity bills. More importantly you won’t be scrambling about on steps changing bulbs and that can save considerably more than money.