LED Knowledge Bank

Design and Installation

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Design criteria

Lighting design needs to achieve many things:

Adequate light for occupants

  • Provide task lighting / sufficient illuminance on the work plane.
  • Provide accurate colour rendering.


  • Allow for safe movement around the building.
  • Emergency lighting.

Visual comfort

  • Provide appropriate colour temperature.
  • Avoid glare e.g. distracting reflections on computer screens.
  • Avoid shadows.
  • Achieve minimum uniformity levels for visual comfort.


  • Provide the require ambience, along with accent lighting to highlight features of the building.

The design process

1. Start with a survey

All lighting installations and LED retrofits need to start with a survey of the premises to produce a map of the building showing dimensions as well as task areas, corridors, meeting rooms, reception areas etc.

In order to design an efficient lighting system it is essential to understand building use and also patterns of use – occupancy hours and intermittency of occupancy (allowing savings through the use of presence / absence detection). The survey should also review the potential for daylight harvesting.

Finally, in a retrofit situation, the survey should include a thorough audit of the lights and controls already in place.

2. Establish target lighting levels

Most lighting standards / codes use illuminance (luminous flux / m2) measured in lux as the main  quantitative criterion for lighting design.

For example recommended levels of lighting on the work plane for an office environment are as follows:

  • 300-500 lx working at computer screens;
  • 500 lx general offices;
  • 750 lx drawing boards.

There are then recommended levels for background illuminance, cylindrical and vertical illuminance. These can be achieved using a combination of direct light and reflected light.

Note that the recommended levels are for maintained illuminance. Higher illuminances are achieved initially with new lamps and clean luminaires. It is usually advisable to use dimming controls at the outset to dim the lights down to the desired level.

Maintained illuminance is the expected output at the end of the life of the lighting system (usually the L70 useful life), when lamps have aged.

The L70 useful life: the time for 50% of a batch of products to fade to 70% of their original light output (when driven under constant current drive conditions). 70% of the initial light output is usually deemed to be the value beyond which the light output becomes unsuitable for purpose.

3. Choose appropriate luminaires / use a lighting designer if necessary

The next step is to choose appropriate light fittings for the environment. For most working and educational environments, there is a fairly standard range of fittings to choose from. In general, once a style has been chosen the main variables to be determined are colour temperature, the lay-out of the fittings and the controls.

However for retail or hospitality environments and for residential lighting, the choice is far greater and we generally recommend that a lighting designer is used to achieve the required aesthetic / ambience. We can assist with this.

4. Model the proposed lighting using software

The building and proposed lighting scheme should be modelled using lighting software to ensure the required lighting level and uniformity is achieved, whilst minimising glare.

5. Controls

Once the lighting scheme has been designed, controls should then be specified with a view to enhancing user comfort and flexibility, and reducing energy bills.

Controls allow:

  • interaction with users;
  • adjustable brightness;
  • occupancy detection;
  • time controls;
  • dimming / switching when sufficient daylight is available (daylight harvesting).

For more information, see our Buyers Guide – Controls.

6. Emergency lighting

Add in emergency lighting as necessary.

7. Test

Before rolling out a lighting scheme, it is advisable to test some fittings in situ, particularly when colour temperature is being changed.


For large commercial clients, we offer LED lighting as a service. There is no upfront cost for the design, installation or maintenance of the system. Instead it is paid off from the bill savings over 5 years.

Find out more


Once the design and testing stage is complete, the lights can be installed. We will produce a schedule of works to minimise disruption and downtime, potentially working out of hours as required.