Energy Reduction

Lighting

Lighting makes up 20 percent of energy consumption in commercial buildings, so it's an important part of planning an energy-efficient facility. The type of building, occupant traffic, and occupancy schedules all affect the type of lighting fixtures used in commercial buildings. Those may include:

    undefined            Fluorescent

undefined        High-density discharge

    undefined           LEDs

Lighting technology makes certain fixtures more suitable in different environments, so efficiency and color rendition are maximized.

Lighting Technology Comparison

Type

Efficiency
(lumens per watt )

CRI*

Lifespan
(hours)

Fluorescent

30-110

50-90

7,000-30,000

Metal Halide

70-115

70-90

5,000-20,000

High-pressure Sodium

50-114

25

16,000-24,000

LED

50-100

70-90

35,000-100,000

*CRI (Color Rendition Index) is rated on a scale of 1 to 100.

Energy-saving strategies

Use LED exit signs

According to the U.S. Department of Energy, exit signs use 30 billion kilowatt hours and have an operating cost of about $2 billion. When replacing exit signs, use LEDs or self-luminous technology that meets  Federal Energy-Efficiency Standards . The most cost-effective solution involves installing a retrofit kit (rather than replacing signs).

Take into account the age of existing lighting fixture, installation, maintenance, and energy costs. All exit signs must consume a maximum of 5 watts.  This eliminates all incandescent and CFL technologies!

Five lighting options are available for use in exit signs (see the chart below):

  • Incandescent  lighting is the least efficient with the shortest lamp life (six months).
  • Fluorescent  lighting has a higher upfront cost, but can have a longer lifespan (2-3 years) and a brighter light.
  • LEDs  have a high upfront cost and lower light output, but have a longer lifespan (6-10 years) and high efficiency.
  • Electroluminescent  exit signs are highly efficient and can last up to 30 years, but come with a high initial cost. 
  • Self-luminous  exit signs do not require any energy. However, they are extremely expensive and potentially dangerous due to the use of radioactive decay of tritium.

 

Type

Life (Years)

Initial Cost ($)

Annual Operating
Cost ($) *

Annual Ownership
Cost ($) **

Incandescent

0.5

6

35

47

Fluorescent

1-2

10

12

27

LED

6-10

16

3

5

Electroluminescent

10-30

65

0.40

4

Self-luminous

10-20

100

0

7

*Annual energy and maintenance costs 
**Initial costs divided by the average life, plus annual operating cost

To calculate energy savings, use the  ENERGY STAR calculator .

Use low-wattage HID metal halide lamps in parking lots

HID lamps are commonly used for outdoor lighting or high indoor ceiling lighting.  The most commonly used HID lamps include:

  • Mercury vapor:  oldest, long life span, low efficiency
  • Metal halide:  include metal halide and mercury gasses, improve efficiency and color rendition
  • High-pressure sodium:  use both sodium and mercury, long life span and high efficiency

Metal halide lamps decrease energy usage, and give off a brighter light. reducing the number of fixtures necessary in an area.

Retrofit lighting systems

Retrofitting a lighting system reduces energy usage, lowers costs, and increases worker productivity. Also. t he use of lighting upgrades may be eligible for tax deductions. For more information on incentives in your area, see Tax Deductions for Commercial Buildings or Database of State Incentives for Renewables and Efficiency

To improve efficiency, combine efficient lighting fixtures with task lighting and controls.  Utilize energy efficient systems, such as:

  • Fluorescent lamps:  use less energy and longer lifespan
  • Electronic ballasts:  quieter with better lighting quality
  • Task lighting:  directs lighting to specific areas, reducing energy usage and overhead light use
  • Reflectors:  aluminum sheets in lighting to divert light
  • Manual and automated lighting controls:  allow lighting to be adjusted by time of day

Automated lighting control s and sensors manage lighting in unoccupied areas such as conference rooms, storage rooms, and restrooms.  Dimming controls and timers help eliminate artificial light.

Energy codes enforce the use of these lighting controls (ex: ASHRAE 90.1-2010 Energy Standard for Building, require standards for both indoor and outdoor lighting).

Additional Green Initiatives

  • Use LED or compact fluorescent lights . LEDs are often used due to their long lifespan and high efficiency. Because of their durability, the lifespan of LEDs can last upwards of 50,000 hours.
  • Replace T12 fluorescent lamps with T8 fluorescent lamps . Linear fluorescent lights are used in offices, commercial, and industrial buildings. The "T" stands for tubular and represents the diameter of the light in eighths of an inch.  The smaller the number, the more efficient the light is , so T8 fluorescent lamps are more efficient and brighter than T12 fluorescent lamps.
  • Use natural sunlight and dimmers  in lobbies, hallways, and indoor pool areas to reduce energy usage.

Download our Green Lighting Checklist