This guest blog comes from Mason Cole, MA Politics and Contemporary History student and Sustainability Champion Assistant (SCA), supporting the King’s Energy Team.

To me, lighting always seemed like a pretty alien concept. You move into a house already fitted with a certain kind of lightbulb. When they run out you survive the darkness for a few days until your landlord replaces the lightbulb or one of your more science-minded housemates gets irritated enough to figure out how to switch it. Added to the fact that there are so many options on the market, the technical names and language can make choosing the right lightbulb overwhelming.

Lighting is actually far simpler than we’re led to believe. You want to figure out three things: the size of your lightbulb fixture, your desired luminosity and the type of lightbulb technology you’d like. We focus here on the latter.

What are the options?

There are four main options on the market: incandescent, halogen, CFL and LED lightbulbs, but what are they and how are they different?

Incandescent: These are the classic – your OG lightbulbs if you like. They contain a small filament that is heated until it glows. Chances are when you think of a lightbulb, this is the one that you think of. The problem is, incandescent bulbs emit 90% of their energy as heat and if you retain a brightness of 800 lumens your energy cost is £4.38 per bulb, per year.

Halogen – These are pretty similar to incandescent lightbulbs except they also have a small capsule containing halogen gas. This capsule helps prolong the life of the lamp and keeps it clear as the reaction “recycles” the halide gas within the capsule rather than depositing it inside the lamp. However, they are significantly more expensive to run, and the European Union banned the import and production of Halogen bulbs in 2018, so there goes that option!

CFL – CFLs, or Compact Fluorescent Lamps, are those fancy twisted bulbs. This “twist” is actually a glass tube filled with mercury vapour and gas with an electrode at either end. When an electric current passes through the tube, it ignites the mercury vapour and creates UV light. This is invisible to the naked eye so there is a phosphor coating on the tube which, when it comes into contact with the ignited gas, fluoresces…get it? Not only do they look cool, but CFLs are up to 70% more energy-efficient than incandescent bulbs and they last much longer.

LEDs – The new kid on the block. LEDs (Light-Emitting Diodes) work by sending an electrical current through a microchip which illuminates the LED…modern stuff! LEDs really are modern, and the future of lighting. The annual running cost of an LED bulb at 800 lumens is £0.92…yes you read that right. They also use 90% less energy than incandescent bulbs and can last up to 25 years.

So what is King’s doing?

Here at King’s, we recognise the potential of LEDs and are working to switch our existing bulbs over. The Franklin Wilkins Building, Macadam and New Hunts House are fully LED, while there are currently two projects for Rayne Building common areas, some labs and Britannia House to convert to LED. We have also commissioned a survey of all the campuses to find out our current lighting status and where we need to upgrade to LED.

For more information on recognising your lightbulbs and the benefits of switching to LED, tune in this Tuesday 13th April for our #TakeoverTuesday on King’s Sustainability Instagram. And as always, feel free to get in touch if you’d like to get involved with Energy at King’s.