February 9, 2009

Lighting Your Way to Energy Efficiency

Vestina F. Crayton, Extension Specialist – Urban Sustainability

Whether at home or in the office, proper lighting is one of the simplest ways you can increase the energy efficiency of a building. According to the Energy Information Administration world energy consumption is projected to increase by 71% from 2003 to 2030. The Environmental Protection Agency has determined that lighting consumes approximately 23% of the electricity used in buildings. According to Energy Star , “if every American home replaced just one light bulb with an ENERGY STAR qualified bulb, we would save enough energy to light more than 3 million homes for a year, more than $600 million in annual energy costs, and prevent greenhouse gases equivalent to the emissions of more than 800,000 cars.”

There has been much talk about replacing high energy consumption bulbs with energy efficient ones. But where do you start and what are you looking for? One size does not fit all. Regardless of which energy efficient product you decide will best fit your individual needs, take a look at and consider the following four things before you purchase that next bulb.

Lighting Terminology
Watt and lumen are two terms that you should know. Watt is the unit of measure for the energy used to produce the light output. Lumen is the unit of measure for the light output. When replacing a light bulb with a more energy efficient one, such as a compact fluorescent light (CFL), you should look for the number of lumens when determining which light bulb to select. This information is important because you want to identify the number of lumens equivalent to the bulb to be replaced. The chart below illustrates this point. A common household bulb is a 60 watt incandescent. To achieve the same brightness with a compact fluorescent light, you should select a bulb that uses only 13-15 watts because it will produce 800 lumens of light. Same light output, less energy.

Source: http://www.energystar,gov/

Energy Use for Incandescent Light Bulbs(Watts)

Minimum Light Output(Lumens)

Energy Use for commonENERGY STAR qualified CFLs (Watts)



4 to 9



9 to 13



13 to 15



18 to 25



23 to 30



28 to 40



30 to 52

Dim it
Utilizing a dimmer switch is another option to consider. Dimmer switches have three primary benefits: energy conservation, extended bulb life and flexibility in creating room ambience. For instance, you may choose to install a dimmer on the general light source used in a family room. Depending on the activity, you can adjust your light. If you are just “hanging out” or relaxing with family and friends, you may not need or want the full brightness of your light. However, if you’re doing housework you may use the full capacity. How about the bathroom? A bright light, first thing in the morning, is usually not welcomed. A dimmer lets you adjust your light gradually.

Right Light, Right Space
Using the right light in the right space can be accomplished by layering light sources. What does “layering light sources” mean? Layering light sources is combining natural and artificial light to achieve efficient and optimum lighting performance. There are three basic categories of light: general, task, and accent. General lighting provides uniform lighting throughout the space such as a chandelier or any other overhead lighting option. Task lighting provides direct light to complete a specific function such as a desk lamp. Accent lighting highlights a particular object such as a piece of art work. Consider the activities in your space. This will help you determine the appropriate lighting.

Consider the daylight and modify your habits
How much direct light does your space get during the day? Try this exercise: select a frequently used room in your home and watch the sunlight patterns throughout the day. This will give you a little insight on the type of lighting required for that space. Many of us are creatures of habit. If you have an eat-in kitchen with a window that faces the east, you may not need to flip that light on when you’re sitting down for breakfast.

Your attitude is probably the most critical element in making any change. Taking the time to educate yourself about lighting is important, however, making the effort to implement better choices, no matter how small, can provide short and long term benefits for the environment, your quality of life and your finances.

To learn more about maximizing and creating more energy efficient lighting systems, join me for the online Webinar, “Lighting Your Way to Energy Efficiency”, where I will explore in more detail some of the best lighting practices. Visit and sign up through the online registration option. This Webinar, or online informational session, is a live broadcast and attendants have the ability to ask questions and interact with the presenter. The Webinar is free, and only requires a PC or Mac complete with speakers or headphones.

Winchip, S. M. (2008). Fundamentals of Lighting, Malaysia: Fairchild Publications, Inc.
Environmental Protection Agency: Energy Efficient Lighting
Energy Star: Lighting Products

To learn more about
LED Lighting
Fluorescent Lighting

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