City Projects in Energy Efficiency and Conservation

Lighting

Lighting represents approximately 22% of all electricity consumed in office buildings. Thus, lighting is a major portion of total building operating costs. Retrofits to lighting systems can yield savings as high as 40% of current costs can easily be fit into routine building maintenance. Retrofits are especially effective in buildings designed pre-1990s, before the widespread use of personal computers. Click here for more lighting statistics.

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When retrofitting a lighting system, consider two related system components: the ballast and controls. Replacing magnetic ballasts with basic electronic ballasts can save a minimum of 12% of energy consumption, more if you invest in premium electronic ballasts. Premium ballasts come in three main types: instant-start, program-start and dimmable. Controls and sensors, which should be matched to the appropriate ballast, greatly improve efficiency and offer higher flexibility to the end user. Occupancy controls shut off lights in empty areas and photosensor controls dim or shut off lights when natural light renders these unnecessary. Either control system can also come equipped with a timer.

New technological improvements in compact fluorescent bulbs have also dramatically reduced energy consumption while improving light quality. Switching out T12 fluorescents for efficient T8s results in higher efficiency (i.e., fewer watts per lumen). T8s last longer, requiring less maintenance over the useful life of the lamp as well as less waste in local landfills. Because light quality is also better, fewer fixtures per square foot are needed, making de-lamping possible. Fewer watts per fixture and fewer fixtures per square foot result in lower cooling loads, which mean that related cooling costs from operating climate control equipment are also reduced.

Light emitting diode (LED) lighting systems, which reduce electricity consumption by up to 85%, have proven to be very effective in applications where brightness, visibility and long life are important, such as in exit signs and traffic signals.

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Read our Local Governments Best Practices Guide for ideas on energy-efficient lighting.


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