What Are The Most Efficient Office Lights?
Lighting for your office can be a significant, ongoing expense. According to the Energy Trust of Oregon, lighting accounts for about 35 percent of electricity use in a typical commercial building in the United States. Choosing the most efficient office lights can result in significant savings.
The most basic measure of lighting efficiency is the number of lumens a fixture generates per watt of energy consumed. This can vary from as low as 43 watts per lumen for a compact fluorescent lamp to as much as 104 watts per lumen for a T5HO fluorescent lamp with electronic ballasts.
Since it generates less heat, more efficient lighting can also reduce energy use for cooling your office.
Another factor to consider is a light source’s color rendering index, or CRI. Most interior lighting systems meet the minimum standard of 80 (out of 100) on this index, so it is probably not a significant issue. Nevertheless, it’s a good idea to have a lighting professional bring a fixture to your workplace for a test drive.
One can also assign a correlated color temperature (CCT) to a light source. Measured in degrees Kelvin (K), the CCT indicates the color present in light. A candle has a low score of around 1,500, indicating “warm” light that contains some red. Pure white light has a CCT of about 3,500, while daylight casts some blue light and has a CCT in the area of 6,500.
Several lamp types have CCTs in the range from 2,700 to 5,000. Compare this to a CCT of around 2,600 for a standard incandescent lamp. Again, when deciding on your office lighting, ask a lighting professional to test various light sources at your office to see what looks best.
Determining the Most Efficient Office Lights for Your Workplace
Let’s look at some specific types of lighting and summarize their attributes, starting with the most energy-efficient lights and working our way down. Remember that these are general guidelines, and other considerations, such as installation cost, may be just as important as energy efficiency. This review won’t discuss the CRI or color temperature, as all the choices are satisfactory in this regard.
A T5HO fluorescent fixture with electronic ballasts generates about 92 to 104 lumens per watt. This lamp should last from 30,000 to 40,000 hours. It is mostly used in larger installations and so may not be appropriate for your office.
A T8 high-performance fluorescent with electronic ballasts puts out from 86 to 96 lumens per watt and should last 24,000 to 42,000 hours. This lamp is a good choice for general lighting in spaces with lower ceilings, such as offices and retail spaces.
A T5 with electronic ballasts issues from 83 to 93 lumens per watt and has a life of 30,000 to 40,000 hours. This is another good choice for offices.
New LED lights generate from 60 to 90 lumens per watt and last up to 50,000 hours. These are another good choice for general office lighting. They don’t emit heat, they come up to full light immediately, and they can be dimmed. However, LED replacement lamps are not as efficient, putting out only 45 to 65 lumens per watt.
Hard-wired compact fluorescent lamps issue 43 to 71 lumens per watt but only last from 6,000 to 12,000 hours. These lamps can replace incandescent lamps in existing fixtures.