Lighting
When assessing the lighting needs of your building, first consider who is using the space and what activities are being carried out within it. Our requirement for lighting varies depending on the tasks being performed. For instance, if your space accommodates customers or visitors, it's likely you'll want to create a well-lit, inviting atmosphere. Whereas walking down a corridor is a relatively simple visual task and doesn’t require as much light. In an office environment, the amount of light needed to view a computer screen differs from that needed to read a printed report.
It’s also important to understand the occupancy patterns of the space and when lighting is required. Is the building only occupied during typical office hours? Is a particular room only in use for a few hours each day? Are people constantly entering and leaving the room within a short period? Both the bulbs themselves, and their control, play significant roles in the building’s lighting energy use.
Designing an efficient lighting system
Once you know how the building is used, you can then review whether there are any improvements that could be made to reduce your lighting bill. Reviewing your bulb choices can be a useful first step. LEDs are the most common energy efficient bulb on offer.
What is an LED?
Light emitting diodes, or LEDs, are efficient, turn on instantly at full brightness, and are available to fit almost every light fitting in a building. An LED works by producing light from the electricity flowing through the bulb.
Select the right lumen value
With traditional bulbs, we used watts to determine the brightness of a bulb, but watts measure power consumption rather than brightness. Energy-efficient bulbs use fewer watts, so it is best to look at lumen output to determine how bright it’s going to be.
This table compares the wattage of traditional bulbs and approximate equivalent lumen values of LEDs.
Select the right colour
Low energy light bulbs imitate traditional light bulbs, so if you prefer a particular colour, there should be a close match with the new energy-efficient lighting.
‘Soft white’ or ‘warm white’ bulbs provide a cosy glow that is best for general lighting, while ‘cool white’ or ‘pure white’ are ideal for focussing on tasks, or any area that requires clear vision.
The colour rendering index (CRI) of a bulb shows you how well a bulb will illuminate a chosen colour. Two bulbs can have the same colour, but the bulb with a higher CRI will show colours more accurately than the other.
The bulb’s packaging will indicate the CRI alongside the lumen value. A CRI of 80 or more is appropriate for many tasks.
What are the benefits of upgrading to LED?
If there are any incandescent or halogen bulbs in your building, upgrading them to LED can reduce your electricity consumption and your electricity bill. In addition:
• They last longer than conventional light bulbs reducing replacement costs.
• LEDs produce very little waste heat compared to conventional sources, reducing the need for additional cooling on warm days.
Potential savings switching traditional or halogen bulbs for LEDs
Many office and work environments are lit by fluorescent tubes. These vary in efficiency, with modern thin tubes (T5s) being the most efficient and the older, thicker tubes being the least efficient. All fluorescent tubes are more efficient than traditional incandescent bulbs, but even the most efficient tubes are not as efficient LEDs. Compact fluorescent bulbs – designed to fit into domestic style fittings – are not quite as efficient as the best straight tubes.
Modern fluorescent tubes are often fitted in mounts with a reflector to direct more light in the desired direction, and this will improve overall system efficiency. Some also have diffusers over the bulbs, which can improve the look and feel but will tend to reduce efficiency, especially if the diffuser isn’t kept clean.
Replacing a fluorescent lighting system with an LED lighting arrangement can be relatively expensive as you will often need to change the fittings, not just the tubes.
Understanding when and how each area of the building is used will help determine the type of controls needed.
For instance, spaces with varying occupancy throughout the day may benefit from occupancy sensors that automatically adjust lighting levels based on movement detection, reducing energy waste during periods of low activity.
You should also consider the flexibility and ease of use of the lighting controls, especially if you need other people to interact with them. Intuitive controls allow occupants to adjust lighting according to their preferences and tasks.
Advanced controls like daylight sensors can optimise energy savings by automatically dimming or switching off artificial lights in response to available natural light, further reducing energy consumption while maintaining comfortable lighting levels.
Elgin Tennis Club installed modern, energy-saving floodlights at its Cooper Park site after receiving £18,000 from the Scottish Government’s interest-free SME loan with cashback. The site had 18 500w and 750w lights that were used between 350 and 400 hours each year. Only 11 LED improved the experience for players and provided savings to the 150-member club of around £1,000 a year.
Inch Park Community Sports Club received £8,280 to install solar PV and upgrade its lighting units to LED lighting throughout. The aim of the project was to lower energy use and running costs of the facility so that it could offer reduced hire rates for community groups. Lessons learned include ensuring that contractors and suppliers are aware of, and agree to work to, significant dates including start and completion dates and ideally have these written into the contract.
Nairn Community and Arts Centre in Moray upgraded the building’s internal and external lighting, including the theatre’s lighting grid, to energy efficient LEDs expected to reduce the centre’s electricity usage by 75%.
