Low energy lighting

Low Energy Lighting

Low energy lighting has become more popular in recent years, mainly owing to higher energy bills and the cost of maintaining inefficient lighting systems.

Well over a third of commercial building’s use of energy and up to 20% of domestic household’s is consumed by the lights. A holistic low energy lighting strategy almost always offers the possibility of an enormous reduction in the amount of electricity consumed and studies show that the correct level of lighting improves health and wellbeing. Many rooms are over lit.

Low energy lighting technology has advanced in leaps and bounds and low energy lighting retrofit is now available in almost any circumstance. Low energy lighting products offer long life and are now aesthetically pleasing.

Paying For Itself

The easiest way to say money on electricity is to change your lighting.

The fittings for low energy lighting typically last twice as long as conventional ones, they use a fraction of the energy, the bulbs last many times longerand no costly transformers are required. What might not be so obvious however is the fact that the wiring itself should last much longer. Less electricity running through the wires creates less heat and so reduces wear and tear on the wiring.

low energy lighting

replacement led bulbs Edison screw


The building itself will also be cooler. The principle reason low energy lighting saves so much on electricity is that it emits much less heat, and a reduction in heat emission has a double saving in reduced air conditioning costs. The lower wattage requirement also significantly extends the lifespan of emergency lighting batteries.

Businesses qualify for low cost finance to fit low energy lighting but given the probable savings most businesses and households would benefit financially even with installations funded at commercial loan rates.


The Carbon Trust advises businesses on the readily available government and privately sponsored self-funding schemes.

carbon trust logo

carbon trust logo

What’s available varies throughout the UK. At the time of writing businesses in Northern Ireland and Wales qualify for 0% interest loans for low energy lighting projects. Different schemes and the Action Energy programme are available for low energy lighting elsewhere. All businesses in the UK are allowed to write off 100% of the capital costs for tax purposes in the first year leaving any interest charges to be claimed against taxable profit year on year.

Low Energy Lighting Strategy

An overall (holistic) low energy lighting solution is arrived at from three directions

  • Installation of low energy lighting hardware, typically LED lighting and T5 retrofit
  • use of lighting controls such as occupancy and daylight sensors
  • regular low energy lighting maintenance and adoption of a strategy for reducing the artificial lighting requirement as a whole

Low Energy Lighting Hardware

low energy lighting

led pin fitting

Simply replacing the existing bulbs with one of the range of low energy ones now available is a cheap low energy lighting solution.

But understanding the characteristics of the various low energy lighting bulbs and units, is a minefield for the uninitiated to navigate. The suitability of each type needs to be matched up with the purpose for which it is proposed. It’s not possible to buy any available low energy lighting bulb and assume it can be used in all fittings.

Compact Fluorescent Lamps

low energy lighting

led replacement tube

The most universal low energy lighting hardware is Compact fluorescent lamps (CFL). They use as much as 80% less energy for the same output of light as a conventional bulb. Over a 15 years period that amounts to a saving of one megawatt hour of electricity and half a tonne of CO² simply by using a low energy lighting lamp instead of an old style bulb.  These are the type of low energy lighting bulbs readily available in supermarkets and can be plugged into a conventional light fitting.

Part L(1) of the Building Regulations now requires that all new houses have a low energy lighting pendant set which uses only four–pin 10/13W bulbs. These low energy lighting units have high frequency electronic control to achieve quick flicker–free starting and are usually placed in the hall or landing where lights are left on the longest.

Light Emitting Diodes (LED)

low energy lighting

replacement GU10 for spot lights

Light emitting diodes (LED) are a more advanced and all round versatile low energy lighting solution. Their bulbs last 5 times as long as a fluorescent, and up to 100 times as long as an old style bulb. The difficulty at the moment is that they can only produce a small source of light. Osram and Phillips estimate that it may take five years before they advance sufficiently to be able to provide low energy lighting for a full room. They are nevertheless already highly suited to decorative low energy lighting and as part of the low energy lighting installation as a whole they can still provide most of what is required.

Fluorescent Lights

T12 and T8 halophosphor tubes with triphosphor fluorescents are the fluorescent version of low energy lighting. They have longer life, better colour rendering, and maintain higher lumen over time, than traditional fluorescents at running costs of up to 30% less, and need less maintenance.

low energy lighting

Std fluorescent fitting

But that might only be the start of their cost reduction contribution in the low energy lighting installation as a whole. Changing the traditional switch start control to high frequency, combined with low energy lighting control, can save a further 20% in energy,

Daylight and Occupancy Sensors

Automatic controls are central to any complete low energy lighting project. But careful thought needs to be given what type of controls are installed. Automatic switching, depending on occupancy and light levels, is achieved by automatic dimmers and on/off switches. Automatic dimmers can be expensive but they allow ‘daylight harvesting’, (taking advantage of unpredictably varying light levels outside). Dimmers have the further advantage of prolonging bulb life by dimming the low energy lighting lamps down to virtually nothing rather than switching them on and off. Switching on and off significant reduces the longevity of the bulb, so considering the low electricity consumption of the low energy light bulb and its higher initial cost compared with a traditional bulb, the economics mitigate in favour of leaving a low energy lighting bulb on, but dimmed to very low level of consumption.

Low Energy Lighting Automatic Control Set Up

low energy lighting

lighting control from i phone

Occupancy sensors are central to low energy lighting solutions and are a nice addition to any home. Apart from the safety benefits of the light coming on when someone enters a space we invariably forget to turn lights off. So the savings mount up.

Reducing the requirement for artificial lighting

By focussing the light where it is required, fewer fittings and therefore fewer bulbs are needed to achieve the same level of lighting in the parts of the room where it is required and avoiding over lighting has the added advantage of improving the appearance and comfort of the room. A similar effect is achievable at minimal or no cost by careful use of table lamps.

When designing the low energy lighting system as part of a wider project, designing the walls ceilings and floors to reflect light where possible has the same effect and can reduce construction and equipment costs.



KCS will be returning to the subject of the various low energy lighting solutions from time to time and would appreciate any feedback and requests from readers.