Best Practice Guide

Local Governments

Introduction

Planning an Energy Program

Funding and Approval

Education

Lighting

Offices and Workstations

Daylighting

Hallways and Corridors

Restrooms and Closets

Outdoor Areas

Signage

Central HVAC System

Procurement Policy

Building Envelope

Demand Response

Distributed Generation

Water Use

Motors

Food Service

Resources and Appendices

Lessons Learned


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Lighting

Offices and Workstations

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Lighting represents approximately 22 percent of all electricity consumed in commercial office buildings. Thus, lighting is a major portion of total building operating costs. Retrofits to lighting systems can yield savings as high as 40 percent of current costs, and can easily be fit into routine building maintenance.

Retrofits are especially effective in buildings designed pre-1990s, before the widespread use of personal computers. As work moves away from the desktop and onto the computer screen, modern workstations require less ambient light

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 percent 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, 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 fluorescent luminaires have also dramatically reduced energy consumption while improving light quality. Switching out T12 fluorescents for efficient T8s results in higher efficacy (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 delamping 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.

Despite these dramatic cost savings, many businesses have been slow to turn over outdated T12s. Of the 1.5 billion fluorescent lamps installed in the U.S. commercial sector, 58 percent are still T12s. This is a missed opportunity. Typically, lighting retrofits recoup costs quickly and are excellent, low-risk investments.

There are two related system components to consider as part of any lighting retrofit: the ballast and controls. Replacing magnetic ballasts with basic electronic ballasts can save a minimum of 12 percent 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, 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.

What is a “light”?

What is a "light"?

All lights have a lamp, commonly but incorrectly referred to as the "light bulb." The fixture connects and positions this lamp to its energy source. In fluorescent and high intensity discharge (HID) fixtures, the energy supply is modulated through a ballast. Halogen and incandescent fixtures, on the other hand, connect directly to the energy supply. Taken together, the lamp, ballast, and fixture are called a "luminaire" - light is the product of a luminaire.

What's the difference between fluorescent fixtures, then?

Fluorescent fixtures are named by the diameter of the lamp. For example, a T12 is a 1-1⁄2" lamp, a T8 is a 1" lamp, and a T5 is a 5/8" lamp. The trick is to divide the number by 8 to determine the diameter in inches. Besides lamp diameter, fluorescents are sometimes further categorized by their lumen output - standard or high output (HO).

Quick Suggestions

Quick Suggestions

  • Fluorescent lamps are better than high-intensity discharge (HID) lamps.
  • T8s are more efficient than T12s.
  • Super T8s are more efficient than standard T8s.
  • Electronic ballasts (fluorescent or HID) are more efficient than magnetic ballasts.
  • Optimal electronic ballasts are more efficient than generic electronic ballasts.
  • Choosing between instant-start, program-start and dimmable ballasts will depend on the application and local utility rate charges.
  • Redesigning the system so that fixtures are delamped may achieve higher long-term savings than simply retrofitting fixtures.
  • Assess life-cycle cost and benefits of lamps and ballasts.
  • Remember to consider benefits derived from daylighting and reflective surfaces.
  • Little things count, like light-emitting diode (LED) exit signs and outdoor lighting.

Resources

Flex Your Power Product Guide: Controls and Sensors and Lamps and Fixtures

Consortium for Energy Efficiency, High Performance Commercial Lighting Systems Initiative, November 2004.

Northeast Energy Efficiency Partnership, Design Lights Consortium, Knowhow: Office Lighting, 2002.

Energy Design Resources, Design Brief: Efficient Lighting Systems, and Design Brief: Lighting Controls, 1998.

The Illuminating Engineers Society of America, Discover Lighting!

DiLouie, C. Energy Policy Act of 2005 Encourages Energy-Efficient Lighting with Tax Deduction. Lighting Controls Association, Septemeber 2005.