Guidebook for Energy Efficiency in Municipalities

Multiply by the number of lights to give the total energy use of the group of lights
Then, use the greenhouse coefficients to convert the annual electricity use (kWh) to
GHG emissions (tonnes of CO 2 equivalent)
Possible indicators
Total lighting energy use (if available) in the building: trend over time.
Lighting energy use per square metre: monthly, seasonal and annual.
Lighting energy use during and outside working hours (to identify scope for switching
off lights when not required).
Office lighting
Opportunities for savings
Use of daylight
Daylight can often be used effectively by automatically dimming the two rows of lights
adjacent to windows (daylight switching is not recommended in offices because of the
distraction it can cause—although dimming can be used).
Avoid excess lighting
The building owner and the lighting designer usually provide office-standard lighting
before the office space has a tenant and the usage of the space is known. This results in
ceiling-mounted light fittings being used to provide an illumination level suitable for
reading almost everywhere, even though only about 5–10% of the office space will
require this lighting level (e.g., 1 m 2 of desk space per person).